From 90d7eab7d0d5afb6f5d8bf70dd7c857c626b4b63 Mon Sep 17 00:00:00 2001
From: qdust41 <qdust41@gmail.com>
Date: Wed, 8 Apr 2026 02:03:43 -0400
Subject: [PATCH] some ai generated code from claude that does not work

---
 assets/css/app.css                            | 153 ++++++++
 assets/js/ash_rpc.ts                          |  77 ++++
 assets/js/ash_types.ts                        |  65 +++-
 assets/js/index.tsx                           | 347 +++++++++++++++---
 assets/js/upload.ts                           |  23 ++
 lib/mixer/accounts.ex                         |   1 +
 lib/mixer/accounts/avatar_uploader.ex         |  33 ++
 lib/mixer/accounts/user.ex                    |  85 +++++
 lib/mixer/posts/tweet.ex                      |  12 +
 lib/mixer_web/auth_overrides.ex               |   5 +
 lib/mixer_web/components/auth_components.ex   |  51 +++
 .../controllers/page_html/index.html.heex     |   5 +
 .../controllers/upload_controller.ex          |  45 +++
 lib/mixer_web/live/magic_sign_in_live.ex      | 184 ++++++++++
 lib/mixer_web/router.ex                       |   2 +
 ...20260408035350_add_user_profile_fields.exs |  29 ++
 .../repo/users/20260408035351.json            | 133 +++++++
 test/mixer/posts/tweet_like_test.exs          |   6 +-
 .../controllers/page_controller_test.exs      |   3 +-
 19 files changed, 1206 insertions(+), 53 deletions(-)
 create mode 100644 lib/mixer/accounts/avatar_uploader.ex
 create mode 100644 lib/mixer_web/components/auth_components.ex
 create mode 100644 lib/mixer_web/live/magic_sign_in_live.ex
 create mode 100644 priv/repo/migrations/20260408035350_add_user_profile_fields.exs
 create mode 100644 priv/resource_snapshots/repo/users/20260408035351.json

diff --git a/assets/css/app.css b/assets/css/app.css
index 2d465c8..e4efb7e 100644
--- a/assets/css/app.css
+++ b/assets/css/app.css
@@ -1056,6 +1056,159 @@ html, body {
   .mx-compose-wrapper { display: none; }
 }
 
+/* ── Avatar image ── */
+.mx-avatar-img {
+  width: 100%;
+  height: 100%;
+  object-fit: cover;
+  border-radius: inherit;
+  display: block;
+}
+
+/* ── Tweet sub-handle (@username) ── */
+.mx-tweet-subhandle {
+  font-size: 0.78rem;
+  color: var(--mx-muted);
+  font-weight: 400;
+  overflow: hidden;
+  text-overflow: ellipsis;
+  white-space: nowrap;
+  max-width: 120px;
+}
+
+/* ── Profile editor ── */
+.mx-profile-editor {
+  padding: 1.5rem 1.25rem;
+  display: flex;
+  flex-direction: column;
+  gap: 1.25rem;
+  max-width: 480px;
+}
+
+.mx-profile-avatar-section {
+  display: flex;
+  flex-direction: column;
+  align-items: flex-start;
+  gap: 0.5rem;
+}
+
+.mx-profile-avatar-wrap {
+  position: relative;
+  width: 80px;
+  height: 80px;
+}
+
+.mx-profile-avatar-img {
+  width: 80px;
+  height: 80px;
+  border-radius: 50%;
+  object-fit: cover;
+  display: block;
+  border: 2px solid var(--mx-border2);
+}
+
+.mx-profile-avatar-placeholder {
+  width: 80px;
+  height: 80px;
+  border-radius: 50%;
+  background: linear-gradient(135deg, var(--mx-accent) 0%, var(--mx-accent2) 100%);
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  font-size: 2rem;
+  font-weight: 700;
+  color: white;
+  user-select: none;
+}
+
+.mx-profile-avatar-edit-btn {
+  position: absolute;
+  bottom: 0;
+  right: 0;
+  width: 26px;
+  height: 26px;
+  border-radius: 50%;
+  background: var(--mx-accent);
+  border: 2px solid var(--mx-bg);
+  color: white;
+  cursor: pointer;
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  transition: background 0.15s;
+}
+.mx-profile-avatar-edit-btn:hover { background: var(--mx-accent2); }
+.mx-profile-avatar-edit-btn:disabled { opacity: 0.6; cursor: not-allowed; }
+
+.mx-profile-stats {
+  display: flex;
+  gap: 1.25rem;
+  font-size: 0.875rem;
+  color: var(--mx-muted);
+}
+.mx-profile-stats strong { color: var(--mx-fg); }
+
+.mx-profile-field {
+  display: flex;
+  flex-direction: column;
+  gap: 0.375rem;
+}
+
+.mx-profile-label {
+  font-size: 0.75rem;
+  font-weight: 600;
+  color: var(--mx-fg2);
+  letter-spacing: 0.04em;
+  text-transform: uppercase;
+}
+
+.mx-profile-input {
+  background: var(--mx-surface);
+  border: 1px solid var(--mx-border2);
+  border-radius: var(--mx-radius-sm);
+  padding: 0.5rem 0.75rem;
+  color: var(--mx-fg);
+  font-family: inherit;
+  font-size: 0.9375rem;
+  width: 100%;
+  transition: border-color 0.15s;
+  outline: none;
+}
+.mx-profile-input:focus { border-color: var(--mx-accent); }
+.mx-profile-input--readonly { color: var(--mx-muted); cursor: not-allowed; }
+
+.mx-profile-input-wrap {
+  display: flex;
+  align-items: center;
+  background: var(--mx-surface);
+  border: 1px solid var(--mx-border2);
+  border-radius: var(--mx-radius-sm);
+  padding: 0 0.75rem;
+  transition: border-color 0.15s;
+}
+.mx-profile-input-wrap:focus-within { border-color: var(--mx-accent); }
+
+.mx-profile-at {
+  color: var(--mx-muted);
+  font-size: 0.9375rem;
+  pointer-events: none;
+  user-select: none;
+}
+
+.mx-profile-input--handle {
+  border: none;
+  border-radius: 0;
+  padding-left: 0.25rem;
+  background: transparent;
+}
+.mx-profile-input--handle:focus { border-color: transparent; }
+
+.mx-profile-hint {
+  font-size: 0.72rem;
+  color: var(--mx-muted);
+  margin-top: 0.125rem;
+}
+
 /* Narrow phones (≤ 640 px): tighten spacing */
 @media (max-width: 640px) {
   .mx-feed  { padding: 0.625rem; gap: 0.5rem; }
diff --git a/assets/js/ash_rpc.ts b/assets/js/ash_rpc.ts
index 5296cd4..88a8d32 100644
--- a/assets/js/ash_rpc.ts
+++ b/assets/js/ash_rpc.ts
@@ -541,6 +541,83 @@ export async function validateReadUser(
 }
 
 
+export type UpdateProfileInput = {
+  username?: string | null;
+  displayName?: string | null;
+};
+
+export type UpdateProfileFields = UnifiedFieldSelection<usersResourceSchema>[];
+
+export type InferUpdateProfileResult<
+  Fields extends UpdateProfileFields | undefined,
+> = InferResult<usersResourceSchema, Fields>;
+
+export type UpdateProfileResult<Fields extends UpdateProfileFields | undefined = undefined> = | { success: true; data: InferUpdateProfileResult<Fields>; }
+| { success: false; errors: AshRpcError[]; }
+
+;
+
+/**
+ * Update an existing User
+ *
+ * @ashActionType :update
+ */
+export async function updateProfile<Fields extends UpdateProfileFields | undefined = undefined>(
+  config: {
+  tenant?: string;
+  identity: UUID;
+  input?: UpdateProfileInput;
+  fields?: Fields;
+  headers?: Record<string, string>;
+  fetchOptions?: RequestInit;
+  customFetch?: (input: RequestInfo | URL, init?: RequestInit) => Promise<Response>;
+}
+): Promise<UpdateProfileResult<Fields extends undefined ? [] : Fields>> {
+  const payload = {
+    action: "update_profile",
+    ...(config.tenant !== undefined && { tenant: config.tenant }),
+    identity: config.identity,
+    input: config.input,
+    ...(config.fields !== undefined && { fields: config.fields })
+  };
+
+  return executeActionRpcRequest<UpdateProfileResult<Fields extends undefined ? [] : Fields>>(
+    payload,
+    config
+  );
+}
+
+
+/**
+ * Validate: Update an existing User
+ *
+ * @ashActionType :update
+ * @validation true
+ */
+export async function validateUpdateProfile(
+  config: {
+  tenant?: string;
+  identity: UUID | string;
+  input?: UpdateProfileInput;
+  headers?: Record<string, string>;
+  fetchOptions?: RequestInit;
+  customFetch?: (input: RequestInfo | URL, init?: RequestInit) => Promise<Response>;
+}
+): Promise<ValidationResult> {
+  const payload = {
+    action: "update_profile",
+    ...(config.tenant !== undefined && { tenant: config.tenant }),
+    identity: config.identity,
+    input: config.input
+  };
+
+  return executeValidationRpcRequest<ValidationResult>(
+    payload,
+    config
+  );
+}
+
+
 export type ReadMediaFields = UnifiedFieldSelection<mediaResourceSchema>[];
 
 
diff --git a/assets/js/ash_types.ts b/assets/js/ash_types.ts
index 6f2a25e..531230d 100644
--- a/assets/js/ash_types.ts
+++ b/assets/js/ash_types.ts
@@ -25,9 +25,12 @@ export type followsAttributesOnlySchema = {
 // users Schema
 export type usersResourceSchema = {
   __type: "Resource";
-  __primitiveFields: "id" | "email" | "followerCount" | "followingCount" | "amIFollowing" | "myFollowId";
+  __primitiveFields: "id" | "email" | "username" | "displayName" | "avatarUrl" | "followerCount" | "followingCount" | "amIFollowing" | "myFollowId";
   id: UUID;
   email: string;
+  username: string | null;
+  displayName: string | null;
+  avatarUrl: string | null;
   followerCount: number;
   followingCount: number;
   amIFollowing: boolean;
@@ -38,9 +41,12 @@ export type usersResourceSchema = {
 
 export type usersAttributesOnlySchema = {
   __type: "Resource";
-  __primitiveFields: "id" | "email";
+  __primitiveFields: "id" | "email" | "username" | "displayName" | "avatarUrl";
   id: UUID;
   email: string;
+  username: string | null;
+  displayName: string | null;
+  avatarUrl: string | null;
 };
 
 
@@ -71,7 +77,7 @@ export type mediaAttributesOnlySchema = {
 // tweets Schema
 export type tweetsResourceSchema = {
   __type: "Resource";
-  __primitiveFields: "id" | "content" | "likes" | "userId" | "insertedAt" | "state" | "parentTweetId" | "commentCount" | "likedByMe" | "userEmail";
+  __primitiveFields: "id" | "content" | "likes" | "userId" | "insertedAt" | "state" | "parentTweetId" | "commentCount" | "likedByMe" | "userEmail" | "userUsername" | "userDisplayName" | "userAvatarUrl";
   id: UUID;
   content: string;
   likes: number;
@@ -82,6 +88,9 @@ export type tweetsResourceSchema = {
   commentCount: number;
   likedByMe: boolean;
   userEmail: string | null;
+  userUsername: string | null;
+  userDisplayName: string | null;
+  userAvatarUrl: string | null;
   user: { __type: "Relationship"; __resource: usersResourceSchema; };
   parentTweet: { __type: "Relationship"; __resource: tweetsResourceSchema | null; };
   comments: { __type: "Relationship"; __array: true; __resource: tweetsResourceSchema; };
@@ -134,6 +143,27 @@ export type usersFilterInput = {
     in?: Array<string>;
   };
 
+  username?: {
+    eq?: string;
+    notEq?: string;
+    in?: Array<string>;
+    isNil?: boolean;
+  };
+
+  displayName?: {
+    eq?: string;
+    notEq?: string;
+    in?: Array<string>;
+    isNil?: boolean;
+  };
+
+  avatarUrl?: {
+    eq?: string;
+    notEq?: string;
+    in?: Array<string>;
+    isNil?: boolean;
+  };
+
   followerCount?: {
     eq?: number;
     notEq?: number;
@@ -270,6 +300,27 @@ export type tweetsFilterInput = {
     isNil?: boolean;
   };
 
+  userUsername?: {
+    eq?: string;
+    notEq?: string;
+    in?: Array<string>;
+    isNil?: boolean;
+  };
+
+  userDisplayName?: {
+    eq?: string;
+    notEq?: string;
+    in?: Array<string>;
+    isNil?: boolean;
+  };
+
+  userAvatarUrl?: {
+    eq?: string;
+    notEq?: string;
+    in?: Array<string>;
+    isNil?: boolean;
+  };
+
   commentCount?: {
     eq?: number;
     notEq?: number;
@@ -301,26 +352,26 @@ export type tweetsFilterInput = {
 export const followsFilterFields = ["id"] as const;
 export type followsFilterField = (typeof followsFilterFields)[number];
 
-export const usersFilterFields = ["id", "email", "followerCount", "followingCount", "amIFollowing", "myFollowId"] as const;
+export const usersFilterFields = ["id", "email", "username", "displayName", "avatarUrl", "followerCount", "followingCount", "amIFollowing", "myFollowId"] as const;
 export type usersFilterField = (typeof usersFilterFields)[number];
 
 export const mediaFilterFields = ["id", "s3Key", "userId", "tweetId", "user", "tweet"] as const;
 export type mediaFilterField = (typeof mediaFilterFields)[number];
 
-export const tweetsFilterFields = ["id", "content", "likes", "userId", "insertedAt", "state", "parentTweetId", "userEmail", "commentCount", "likedByMe", "user", "parentTweet", "comments", "media"] as const;
+export const tweetsFilterFields = ["id", "content", "likes", "userId", "insertedAt", "state", "parentTweetId", "userEmail", "userUsername", "userDisplayName", "userAvatarUrl", "commentCount", "likedByMe", "user", "parentTweet", "comments", "media"] as const;
 export type tweetsFilterField = (typeof tweetsFilterFields)[number];
 
 
 export const followsSortFields = ["id"] as const;
 export type followsSortField = (typeof followsSortFields)[number];
 
-export const usersSortFields = ["id", "email", "followerCount", "followingCount", "amIFollowing", "myFollowId"] as const;
+export const usersSortFields = ["id", "email", "username", "displayName", "avatarUrl", "followerCount", "followingCount", "amIFollowing", "myFollowId"] as const;
 export type usersSortField = (typeof usersSortFields)[number];
 
 export const mediaSortFields = ["id", "s3Key", "userId", "tweetId"] as const;
 export type mediaSortField = (typeof mediaSortFields)[number];
 
-export const tweetsSortFields = ["id", "content", "likes", "userId", "insertedAt", "state", "parentTweetId", "userEmail", "commentCount", "likedByMe"] as const;
+export const tweetsSortFields = ["id", "content", "likes", "userId", "insertedAt", "state", "parentTweetId", "userEmail", "userUsername", "userDisplayName", "userAvatarUrl", "commentCount", "likedByMe"] as const;
 export type tweetsSortField = (typeof tweetsSortFields)[number];
 
 
diff --git a/assets/js/index.tsx b/assets/js/index.tsx
index 1c7d500..19c5d29 100644
--- a/assets/js/index.tsx
+++ b/assets/js/index.tsx
@@ -17,12 +17,13 @@ import {
   likeTweet,
   unlikeTweet,
   updateTweet,
+  updateProfile,
   readUser,
   followUser,
   unfollowUser,
   buildCSRFHeaders,
 } from "./ash_rpc";
-import { uploadFile } from "./upload";
+import { uploadFile, uploadAvatar } from "./upload";
 
 const queryClient = new QueryClient({
   defaultOptions: { queries: { staleTime: 10_000 } },
@@ -33,6 +34,9 @@ const queryClient = new QueryClient({
 type User = {
   id: string;
   email: string;
+  username?: string | null;
+  displayName?: string | null;
+  avatarUrl?: string | null;
   followerCount?: number;
   followingCount?: number;
   amIFollowing?: boolean;
@@ -50,12 +54,21 @@ type Tweet = {
   state: string;
   media?: MediaItem[];
   userEmail?: string | null;
+  userUsername?: string | null;
+  userDisplayName?: string | null;
+  userAvatarUrl?: string | null;
   insertedAt?: string | null;
 };
 
 // ── Auth context ───────────────────────────────────────────────────────────────
 
-const AuthCtx = createContext({ email: "", userId: "" });
+const AuthCtx = createContext({
+  email: "",
+  userId: "",
+  username: "",
+  displayName: "",
+  avatarUrl: "",
+});
 
 // ── Responsive helper ─────────────────────────────────────────────────────────
 // Returns true when the viewport is wider than 960 px (desktop layout).
@@ -102,6 +115,54 @@ function getAssetHost(): string {
   return appEl?.dataset.assetHost ?? "http://localhost:9000";
 }
 
+// ── Display-name helpers ─────────────────────────────────────────────
+
+function userDisplayLabel(u: {
+  displayName?: string | null;
+  username?: string | null;
+  email?: string | null;
+}): string {
+  return u.displayName || u.username || u.email || "@mixer";
+}
+
+function userHandle(u: { username?: string | null; email?: string | null }): string {
+  return u.username ? `@${u.username}` : u.email ?? "@mixer";
+}
+
+// ── Avatar ───────────────────────────────────────────────────────────────
+
+function Avatar({
+  avatarUrl,
+  name,
+  size = "md",
+}: {
+  avatarUrl?: string | null;
+  name?: string | null;
+  size?: "sm" | "md" | "lg";
+}) {
+  const assetHost = getAssetHost();
+  const initial = ((name ?? "")[0] || "M").toUpperCase();
+  const cls = size === "sm"
+    ? "mx-tweet-avatar mx-tweet-avatar--sm"
+    : size === "lg"
+    ? "mx-tweet-avatar mx-tweet-avatar--lg"
+    : "mx-tweet-avatar";
+
+  return (
+    <div className={cls}>
+      {avatarUrl ? (
+        <img
+          src={`${assetHost}/${avatarUrl}`}
+          alt={name ?? "avatar"}
+          className="mx-avatar-img"
+        />
+      ) : (
+        <span>{initial}</span>
+      )}
+    </div>
+  );
+}
+
 // ── Context menu ──────────────────────────────────────────────────────────────
 
 type ContextMenuItem =
@@ -203,6 +264,7 @@ function CharCount({ current, max }: { current: number; max: number }) {
 }
 
 function ComposeTweet({ onSuccess }: { onSuccess?: () => void }) {
+  const { username, displayName, email, avatarUrl } = useContext(AuthCtx);
   const [text, setText] = useState("");
   const [error, setError] = useState<string | null>(null);
   const [pendingFile, setPendingFile] = useState<File | null>(null);
@@ -304,9 +366,7 @@ function ComposeTweet({ onSuccess }: { onSuccess?: () => void }) {
 
   return (
     <div className="mx-compose">
-      <div className="mx-compose-avatar">
-        <span>M</span>
-      </div>
+      <Avatar avatarUrl={avatarUrl} name={displayName || username || email} />
       <div className="mx-compose-body">
         <textarea
           ref={textareaRef}
@@ -546,12 +606,13 @@ function TweetCard({ tweet }: { tweet: Tweet }) {
       onClick={() => { window.location.href = `/feed/${tweet.id}`; }}
       onContextMenu={(e) => { e.preventDefault(); setCtxMenu({ x: e.clientX, y: e.clientY }); }}
     >
-      <div className="mx-tweet-avatar">
-        <span>M</span>
-      </div>
+      <Avatar avatarUrl={tweet.userAvatarUrl} name={tweet.userDisplayName || tweet.userUsername || tweet.userEmail} />
       <div className="mx-tweet-body">
         <div className="mx-tweet-header">
-          <span className="mx-tweet-handle">{tweet.userEmail ?? "@mixer"}</span>
+          <span className="mx-tweet-handle">{userDisplayLabel({ displayName: tweet.userDisplayName, username: tweet.userUsername, email: tweet.userEmail })}</span>
+          {tweet.userUsername && (
+            <span className="mx-tweet-subhandle">@{tweet.userUsername}</span>
+          )}
           <span className="mx-tweet-dot">·</span>
           <span className="mx-tweet-time" title={tweet.insertedAt ? new Date(tweet.insertedAt).toLocaleString() : undefined}>{timeAgo(tweet.insertedAt)}</span>
           {canModify && (
@@ -754,11 +815,11 @@ function ComposeComment({ parentTweetId, onSuccess }: { parentTweetId: string; o
     el.style.height = `${el.scrollHeight}px`;
   }, [text]);
 
+  const { username, displayName, email, avatarUrl } = useContext(AuthCtx);
+
   return (
     <div className="mx-compose mx-compose--comment">
-      <div className="mx-compose-avatar mx-compose-avatar--sm">
-        <span>M</span>
-      </div>
+      <Avatar avatarUrl={avatarUrl} name={displayName || username || email} size="sm" />
       <div className="mx-compose-body">
         <textarea
           ref={textareaRef}
@@ -803,7 +864,7 @@ function TweetDetail({ tweetId }: { tweetId: string }) {
     queryKey: ["tweet", tweetId],
     queryFn: async () => {
       const res = await readTweet({
-        fields: ["id", "content", "likes", "likedByMe", "commentCount", "userId", "state", "userEmail", "insertedAt", { media: ["id", "s3Key"] }],
+        fields: ["id", "content", "likes", "likedByMe", "commentCount", "userId", "state", "userEmail", "userUsername", "userDisplayName", "userAvatarUrl", "insertedAt", { media: ["id", "s3Key"] }],
         filter: { id: { eq: tweetId } },
         headers: buildCSRFHeaders(),
       });
@@ -825,7 +886,7 @@ function TweetDetail({ tweetId }: { tweetId: string }) {
     queryKey: ["comments", tweetId],
     queryFn: async ({ pageParam }: { pageParam: number }) => {
       const res = await readTweet({
-        fields: ["id", "content", "likes", "likedByMe", "parentTweetId", "userId", "state", "userEmail", "insertedAt", { media: ["id", "s3Key"] }],
+        fields: ["id", "content", "likes", "likedByMe", "parentTweetId", "userId", "state", "userEmail", "userUsername", "userDisplayName", "userAvatarUrl", "insertedAt", { media: ["id", "s3Key"] }],
         filter: { parentTweetId: { eq: tweetId } },
         sort: "insertedAt",
         page: { limit: COMMENTS_PAGE_SIZE, offset: pageParam },
@@ -950,10 +1011,13 @@ function TweetDetail({ tweetId }: { tweetId: string }) {
 
       <div className="mx-detail-body">
         <div className="mx-detail-author">
-          <div className="mx-tweet-avatar">
-            <span>M</span>
+          <Avatar avatarUrl={tweet.userAvatarUrl} name={tweet.userDisplayName || tweet.userUsername || tweet.userEmail} />
+          <div>
+            <span className="mx-tweet-handle">{userDisplayLabel({ displayName: tweet.userDisplayName, username: tweet.userUsername, email: tweet.userEmail })}</span>
+            {tweet.userUsername && (
+              <div style={{ fontSize: "0.8rem", color: "var(--mx-muted)" }}>@{tweet.userUsername}</div>
+            )}
           </div>
-          <span className="mx-tweet-handle">{tweet.userEmail ?? "@mixer"}</span>
         </div>
 
         {editing ? (
@@ -1091,12 +1155,13 @@ function CommentCard({ comment, parentTweetOwnerId }: { comment: Tweet; parentTw
 
   return (
     <article className="mx-tweet mx-comment">
-      <div className="mx-tweet-avatar mx-tweet-avatar--sm">
-        <span>M</span>
-      </div>
+      <Avatar avatarUrl={comment.userAvatarUrl} name={comment.userDisplayName || comment.userUsername || comment.userEmail} size="sm" />
       <div className="mx-tweet-body">
         <div className="mx-tweet-header">
-          <span className="mx-tweet-handle">{comment.userEmail ?? "@mixer"}</span>
+          <span className="mx-tweet-handle">{userDisplayLabel({ displayName: comment.userDisplayName, username: comment.userUsername, email: comment.userEmail })}</span>
+          {comment.userUsername && (
+            <span className="mx-tweet-subhandle">@{comment.userUsername}</span>
+          )}
           <span className="mx-tweet-dot">·</span>
           <span className="mx-tweet-time" title={comment.insertedAt ? new Date(comment.insertedAt).toLocaleString() : undefined}>{timeAgo(comment.insertedAt)}</span>
           {canModify && (
@@ -1169,7 +1234,7 @@ function FollowingFeed() {
     queryKey: ["following_tweets"],
     queryFn: async ({ pageParam }: { pageParam: number }) => {
       const res = await readFollowingFeed({
-        fields: ["id", "content", "likes", "likedByMe", "commentCount", "userId", "state", "userEmail", "insertedAt", { media: ["id", "s3Key"] }],
+        fields: ["id", "content", "likes", "likedByMe", "commentCount", "userId", "state", "userEmail", "userUsername", "userDisplayName", "userAvatarUrl", "insertedAt", { media: ["id", "s3Key"] }],
         sort: "-insertedAt",
         page: { limit: FEED_PAGE_SIZE, offset: pageParam },
         filter: { parentTweetId: { isNil: true } },
@@ -1263,7 +1328,7 @@ function Feed() {
     queryKey: ["tweets"],
     queryFn: async ({ pageParam }: { pageParam: number }) => {
       const res = await readTweet({
-        fields: ["id", "content", "likes", "likedByMe", "commentCount", "userId", "state", "userEmail", "insertedAt", { media: ["id", "s3Key"] }],
+        fields: ["id", "content", "likes", "likedByMe", "commentCount", "userId", "state", "userEmail", "userUsername", "userDisplayName", "userAvatarUrl", "insertedAt", { media: ["id", "s3Key"] }],
         sort: "-insertedAt",
         page: { limit: FEED_PAGE_SIZE, offset: pageParam },
         filter: { parentTweetId: { isNil: true } },
@@ -1428,12 +1493,13 @@ function UserCard({ user }: { user: User }) {
       onClick={() => { window.location.href = `/users/${user.id}`; }}
       onContextMenu={(e) => { e.preventDefault(); setCtxMenu({ x: e.clientX, y: e.clientY }); }}
     >
-      <div className="mx-tweet-avatar">
-        <span>M</span>
-      </div>
+      <Avatar avatarUrl={user.avatarUrl} name={user.displayName || user.username || user.email} />
       <div className="mx-tweet-body">
         <div className="mx-tweet-header">
-          <span className="mx-tweet-handle">{user.email}</span>
+          <span className="mx-tweet-handle">{userDisplayLabel(user)}</span>
+          {user.username && (
+            <span className="mx-tweet-subhandle">@{user.username}</span>
+          )}
         </div>
         {(user.followerCount !== undefined || user.followingCount !== undefined) && (
           <div className="mx-tweet-meta" style={{ fontSize: "0.8rem", color: "var(--mx-muted)", marginTop: "4px" }}>
@@ -1459,7 +1525,7 @@ function UserList() {
     queryKey: ["users"],
     queryFn: async () => {
       const res = await readUser({
-        fields: ["id", "email", "followerCount", "followingCount", "amIFollowing"],
+        fields: ["id", "email", "username", "displayName", "avatarUrl", "followerCount", "followingCount", "amIFollowing"],
         headers: buildCSRFHeaders(),
       });
       if (!res.success) throw new Error("Failed to load users");
@@ -1499,7 +1565,7 @@ function UserDetail({ userId, isStandalone = false }: { userId: string; isStanda
     queryKey: ["user", userId],
     queryFn: async () => {
       const res = await readUser({
-        fields: ["id", "email", "followerCount", "followingCount", "amIFollowing"],
+        fields: ["id", "email", "username", "displayName", "avatarUrl", "followerCount", "followingCount", "amIFollowing"],
         filter: { id: { eq: userId } },
         headers: buildCSRFHeaders(),
       });
@@ -1530,24 +1596,22 @@ function UserDetail({ userId, isStandalone = false }: { userId: string; isStanda
       )}
       <div className="mx-detail-body">
         <div className="mx-detail-author">
-          <div className="mx-tweet-avatar mx-tweet-avatar--lg">
-            <span>{user.email?.[0]?.toUpperCase() ?? "M"}</span>
-          </div>
+          <Avatar avatarUrl={user.avatarUrl} name={user.displayName || user.username || user.email} size="lg" />
           <div style={{ flex: 1 }}>
             <div style={{ display: "flex", alignItems: "center", gap: "12px", flexWrap: "wrap" }}>
-              <span className="mx-tweet-handle">{user.email}</span>
+              <div>
+                <div className="mx-tweet-handle" style={{ fontSize: "1.1rem" }}>{userDisplayLabel(user)}</div>
+                {user.username && (
+                  <div style={{ fontSize: "0.85rem", color: "var(--mx-muted)" }}>@{user.username}</div>
+                )}
+              </div>
               {canFollow && (
                 <FollowButton amIFollowing={amIFollowing} isPending={isPending} onToggle={amIFollowing ? unfollow : follow} />
               )}
-              {isOwnProfile && isStandalone && (
-                <a href="/sign-out" className="mx-btn-cancel" style={{ textDecoration: "none", fontSize: "0.8rem" }}>
-                  Sign out
-                </a>
-              )}
             </div>
-            <div style={{ fontSize: "0.85rem", color: "var(--mx-muted)", marginTop: "6px", display: "flex", gap: "16px" }}>
-              <span><strong>{user.followerCount ?? 0}</strong> followers</span>
-              <span><strong>{user.followingCount ?? 0}</strong> following</span>
+            <div style={{ fontSize: "0.85rem", color: "var(--mx-muted)", marginTop: "8px", display: "flex", gap: "16px" }}>
+              <span><strong style={{ color: "var(--mx-fg)" }}>{user.followerCount ?? 0}</strong> followers</span>
+              <span><strong style={{ color: "var(--mx-fg)" }}>{user.followingCount ?? 0}</strong> following</span>
             </div>
           </div>
         </div>
@@ -1556,6 +1620,193 @@ function UserDetail({ userId, isStandalone = false }: { userId: string; isStanda
   );
 }
 
+function ProfileEditor({ userId }: { userId: string }) {
+  const assetHost = getAssetHost();
+  const qc = useQueryClient();
+
+  const { data: user, isLoading } = useQuery({
+    queryKey: ["user", userId],
+    queryFn: async () => {
+      const res = await readUser({
+        fields: ["id", "email", "username", "displayName", "avatarUrl", "followerCount", "followingCount", "amIFollowing"],
+        filter: { id: { eq: userId } },
+        headers: buildCSRFHeaders(),
+      });
+      if (!res.success) throw new Error("Failed to load user");
+      const results = Array.isArray(res.data) ? res.data : (res.data as any)?.results ?? [];
+      return (results[0] as User) ?? null;
+    },
+  });
+
+  const [username, setUsername] = useState("");
+  const [displayName, setDisplayName] = useState("");
+  const [saveError, setSaveError] = useState<string | null>(null);
+  const [saveSuccess, setSaveSuccess] = useState(false);
+  const [avatarUploading, setAvatarUploading] = useState(false);
+  const [avatarError, setAvatarError] = useState<string | null>(null);
+  const [previewAvatarUrl, setPreviewAvatarUrl] = useState<string | null>(null);
+  const avatarInputRef = useRef<HTMLInputElement>(null);
+
+  // Sync form fields when user data loads
+  useEffect(() => {
+    if (user) {
+      setUsername(user.username ?? "");
+      setDisplayName(user.displayName ?? "");
+    }
+  }, [user?.id]);
+
+  const saveMutation = useMutation({
+    mutationFn: async () => {
+      const res = await updateProfile({
+        identity: userId,
+        input: {
+          username: username.trim() || null,
+          displayName: displayName.trim() || null,
+        },
+        fields: ["id", "username", "displayName", "avatarUrl"],
+        headers: buildCSRFHeaders(),
+      });
+      if (!res.success) throw new Error((res.errors?.[0] as any)?.message ?? "Save failed");
+      return res.data;
+    },
+    onSuccess: () => {
+      qc.invalidateQueries({ queryKey: ["user", userId] });
+      setSaveSuccess(true);
+      setSaveError(null);
+      setTimeout(() => setSaveSuccess(false), 3000);
+    },
+    onError: (e: Error) => setSaveError(e.message),
+  });
+
+  async function handleAvatarChange(e: React.ChangeEvent<HTMLInputElement>) {
+    const file = e.target.files?.[0];
+    if (!file) return;
+    e.target.value = "";
+    if (previewAvatarUrl) URL.revokeObjectURL(previewAvatarUrl);
+    setPreviewAvatarUrl(URL.createObjectURL(file));
+    setAvatarError(null);
+    setAvatarUploading(true);
+    const csrfToken = buildCSRFHeaders()["X-CSRF-Token"] as string;
+    const result = await uploadAvatar(file, csrfToken);
+    setAvatarUploading(false);
+    if ("error" in result) {
+      setAvatarError(result.error);
+      if (previewAvatarUrl) URL.revokeObjectURL(previewAvatarUrl);
+      setPreviewAvatarUrl(null);
+    } else {
+      qc.invalidateQueries({ queryKey: ["user", userId] });
+    }
+  }
+
+  if (isLoading || !user) return <Spinner />;
+
+  const currentAvatarUrl = previewAvatarUrl
+    ? previewAvatarUrl
+    : user.avatarUrl
+    ? `${assetHost}/${user.avatarUrl}`
+    : null;
+
+  return (
+    <div className="mx-profile-editor">
+      {/* Avatar section */}
+      <div className="mx-profile-avatar-section">
+        <div className="mx-profile-avatar-wrap">
+          {currentAvatarUrl ? (
+            <img src={currentAvatarUrl} alt="Your avatar" className="mx-profile-avatar-img" />
+          ) : (
+            <div className="mx-profile-avatar-placeholder">
+              <span>{(user.displayName || user.username || user.email || "M")[0].toUpperCase()}</span>
+            </div>
+          )}
+          <button
+            className="mx-profile-avatar-edit-btn"
+            onClick={() => avatarInputRef.current?.click()}
+            disabled={avatarUploading}
+            title="Change avatar"
+          >
+            {avatarUploading ? (
+              <div className="mx-spinner" style={{ width: "14px", height: "14px", borderWidth: "2px" }} />
+            ) : (
+              <svg width="14" height="14" viewBox="0 0 24 24" fill="currentColor">
+                <path d="M3 17.25V21h3.75L17.81 9.94l-3.75-3.75L3 17.25zm17.71-10.04a1 1 0 0 0 0-1.41l-2.31-2.31a1 1 0 0 0-1.41 0l-1.79 1.79 3.75 3.75 1.76-1.82z" />
+              </svg>
+            )}
+          </button>
+          <input
+            ref={avatarInputRef}
+            type="file"
+            accept="image/*"
+            style={{ display: "none" }}
+            onChange={handleAvatarChange}
+          />
+        </div>
+        {avatarError && <p className="mx-compose-error" style={{ marginTop: "0.5rem" }}>{avatarError}</p>}
+      </div>
+
+      {/* Stats row */}
+      <div className="mx-profile-stats">
+        <span><strong>{user.followerCount ?? 0}</strong> followers</span>
+        <span><strong>{user.followingCount ?? 0}</strong> following</span>
+      </div>
+
+      {/* Email (read-only) */}
+      <div className="mx-profile-field">
+        <label className="mx-profile-label">Email</label>
+        <input
+          type="text"
+          className="mx-profile-input mx-profile-input--readonly"
+          value={String(user.email)}
+          readOnly
+        />
+      </div>
+
+      {/* Display name */}
+      <div className="mx-profile-field">
+        <label className="mx-profile-label">Display name</label>
+        <input
+          type="text"
+          className="mx-profile-input"
+          placeholder="Your display name"
+          value={displayName}
+          onChange={(e) => setDisplayName(e.target.value)}
+          maxLength={50}
+        />
+      </div>
+
+      {/* Username */}
+      <div className="mx-profile-field">
+        <label className="mx-profile-label">Username</label>
+        <div className="mx-profile-input-wrap">
+          <span className="mx-profile-at">@</span>
+          <input
+            type="text"
+            className="mx-profile-input mx-profile-input--handle"
+            placeholder="your_handle"
+            value={username}
+            onChange={(e) => setUsername(e.target.value.replace(/[^a-zA-Z0-9_]/g, ""))}
+            maxLength={30}
+          />
+        </div>
+        <p className="mx-profile-hint">3–30 characters. Letters, numbers, underscores only.</p>
+      </div>
+
+      {saveError && <p className="mx-compose-error">{saveError}</p>}
+      {saveSuccess && <p style={{ fontSize: "0.8rem", color: "var(--mx-green)", marginBottom: "0.5rem" }}>✓ Saved!</p>}
+
+      <div style={{ display: "flex", gap: "0.75rem", alignItems: "center" }}>
+        <button
+          className="mx-btn-post"
+          onClick={() => saveMutation.mutate()}
+          disabled={saveMutation.isPending}
+        >
+          {saveMutation.isPending ? "Saving…" : "Save changes"}
+        </button>
+        <a href="/sign-out" className="mx-btn-cancel" style={{ textDecoration: "none" }}>Sign out</a>
+      </div>
+    </div>
+  );
+}
+
 function MyProfile() {
   const { userId } = useContext(AuthCtx);
 
@@ -1572,7 +1823,7 @@ function MyProfile() {
     );
   }
 
-  return <UserDetail userId={userId} isStandalone />;
+  return <ProfileEditor userId={userId} />;
 }
 
 // ── Mobile bottom nav ─────────────────────────────────────────────────────────
@@ -1691,6 +1942,9 @@ function App() {
   const appEl = document.getElementById("app")!;
   const email = appEl.dataset.currentUserEmail ?? "";
   const userId = appEl.dataset.currentUserId ?? "";
+  const username = appEl.dataset.currentUserUsername ?? "";
+  const displayName = appEl.dataset.currentUserDisplayName ?? "";
+  const avatarUrl = appEl.dataset.currentUserAvatarUrl ?? "";
   const tweetId = appEl.dataset.tweetId || null;
   const page = appEl.dataset.page ?? "feed";
   const profileUserId = appEl.dataset.userId || null;
@@ -1779,7 +2033,7 @@ function App() {
   }
 
   return (
-    <AuthCtx.Provider value={{ email, userId }}>
+    <AuthCtx.Provider value={{ email, userId, username, displayName, avatarUrl }}>
       <QueryClientProvider client={queryClient}>
         <div className="mx-root">
           {isDesktop && (
@@ -1817,7 +2071,12 @@ function App() {
               <div className="mx-sidebar-footer">
                 {email ? (
                   <>
-                    <span className="mx-version" style={{ color: "var(--mx-fg2)" }}>{email}</span>
+                    <span className="mx-version" style={{ color: "var(--mx-fg2)" }}>
+                      {displayName || username || email}
+                    </span>
+                    {username && (
+                      <span className="mx-version">@{username}</span>
+                    )}
                     <a className="mx-auth-link" href="/sign-out">Sign out</a>
                   </>
                 ) : (
diff --git a/assets/js/upload.ts b/assets/js/upload.ts
index 882d7b4..2bbb384 100644
--- a/assets/js/upload.ts
+++ b/assets/js/upload.ts
@@ -9,6 +9,29 @@ export interface UploadError {
   error: string;
 }
 
+export interface AvatarUploadResult {
+  success: true;
+  avatarUrl: string;
+}
+
+export async function uploadAvatar(
+  file: File,
+  csrfToken: string
+): Promise<AvatarUploadResult | UploadError> {
+  const formData = new FormData();
+  formData.append("file", file);
+  const res = await fetch("/upload/avatar", {
+    method: "POST",
+    headers: { "X-CSRF-Token": csrfToken },
+    body: formData,
+  });
+  const json = await res.json();
+  if (!res.ok || !json.success) {
+    return { error: json.error ?? "Upload failed" };
+  }
+  return json as AvatarUploadResult;
+}
+
 export async function uploadFile(
   file: File,
   csrfToken: string
diff --git a/lib/mixer/accounts.ex b/lib/mixer/accounts.ex
index c036cb3..1b38b42 100644
--- a/lib/mixer/accounts.ex
+++ b/lib/mixer/accounts.ex
@@ -4,6 +4,7 @@ defmodule Mixer.Accounts do
   typescript_rpc do
     resource Mixer.Accounts.User do
       rpc_action :read_user, :read
+      rpc_action :update_profile, :update_profile
     end
 
     resource Mixer.Accounts.Follow do
diff --git a/lib/mixer/accounts/avatar_uploader.ex b/lib/mixer/accounts/avatar_uploader.ex
new file mode 100644
index 0000000..a434845
--- /dev/null
+++ b/lib/mixer/accounts/avatar_uploader.ex
@@ -0,0 +1,33 @@
+defmodule Mixer.Accounts.AvatarUploader do
+  use Waffle.Definition
+
+  @versions [:original, :thumb]
+  @extensions ~w(.jpg .jpeg .png .gif .webp)
+
+  def validate({file, _scope}) do
+    ext = file.file_name |> Path.extname() |> String.downcase()
+    if ext in @extensions, do: :ok, else: {:error, "unsupported file type #{ext}"}
+  end
+
+  # Resize to a 256×256 square (centre-crop) and convert to WebP for efficiency
+  def transform(:thumb, _) do
+    {:convert, "-strip -thumbnail 256x256^ -gravity center -extent 256x256 -format webp", :webp}
+  end
+
+  # Store both versions under avatars/:user_id/
+  def storage_dir(_version, {_file, scope}), do: "avatars/#{scope.user_id}"
+
+  def filename(:original, {file, _scope}) do
+    Path.basename(file.file_name, Path.extname(file.file_name))
+  end
+
+  def filename(:thumb, _), do: "thumb"
+
+  def s3_object_headers(:thumb, _), do: [content_type: "image/webp"]
+
+  def s3_object_headers(_version, {file, _scope}) do
+    [content_type: MIME.from_path(file.file_name)]
+  end
+
+  def acl(_version, _), do: :public_read
+end
diff --git a/lib/mixer/accounts/user.ex b/lib/mixer/accounts/user.ex
index c60280d..d5ba7ce 100644
--- a/lib/mixer/accounts/user.ex
+++ b/lib/mixer/accounts/user.ex
@@ -177,9 +177,21 @@ defmodule Mixer.Accounts.User do
         sensitive? true
       end
 
+      argument :username, :string do
+        description "The desired username for the user (letters, numbers, underscores)."
+        allow_nil? false
+
+        constraints match: ~r/^[a-zA-Z0-9_]+$/,
+                    min_length: 3,
+                    max_length: 30
+      end
+
       # Sets the email from the argument
       change set_attribute(:email, arg(:email))
 
+      # Sets the username from the argument
+      change set_attribute(:username, arg(:username))
+
       # Hashes the provided password
       change AshAuthentication.Strategy.Password.HashPasswordChange
 
@@ -211,6 +223,18 @@ defmodule Mixer.Accounts.User do
       get_by :email
     end
 
+    update :update_profile do
+      description "Update the user's public profile (username, display name)."
+      accept [:username, :display_name]
+      require_atomic? false
+    end
+
+    update :update_avatar do
+      description "Store the S3 key of the user's processed avatar thumbnail."
+      accept [:avatar_url]
+      require_atomic? false
+    end
+
     update :reset_password_with_token do
       argument :reset_token, :string do
         allow_nil? false
@@ -256,6 +280,15 @@ defmodule Mixer.Accounts.User do
         allow_nil? true
       end
 
+      argument :username, :string do
+        description "Username chosen during first-time magic link registration."
+        allow_nil? true
+
+        constraints match: ~r/^[a-zA-Z0-9_]+$/,
+                    min_length: 3,
+                    max_length: 30
+      end
+
       upsert? true
       upsert_identity :unique_email
       upsert_fields [:email]
@@ -266,6 +299,32 @@ defmodule Mixer.Accounts.User do
       change {AshAuthentication.Strategy.RememberMe.MaybeGenerateTokenChange,
               strategy_name: :remember_me}
 
+      # Set username on new users (or existing users who haven't set one yet)
+      change fn changeset, _ctx ->
+        case Ash.Changeset.get_argument(changeset, :username) do
+          nil ->
+            changeset
+
+          username ->
+            Ash.Changeset.after_action(changeset, fn _cs, user ->
+              if is_nil(user.username) do
+                user
+                |> Ash.Changeset.for_update(:update_profile, %{username: username},
+                  authorize?: false
+                )
+                |> Ash.update()
+                |> case do
+                  {:ok, updated} -> {:ok, updated}
+                  # Don't fail the sign-in just because username set failed
+                  {:error, _} -> {:ok, user}
+                end
+              else
+                {:ok, user}
+              end
+            end)
+        end
+      end
+
       metadata :token, :string do
         allow_nil? false
       end
@@ -293,6 +352,14 @@ defmodule Mixer.Accounts.User do
     policy action_type(:read) do
       authorize_if always()
     end
+
+    policy action(:update_profile) do
+      authorize_if expr(id == ^actor(:id))
+    end
+
+    policy action(:update_avatar) do
+      authorize_if expr(id == ^actor(:id))
+    end
   end
 
   attributes do
@@ -308,6 +375,23 @@ defmodule Mixer.Accounts.User do
     end
 
     attribute :confirmed_at, :utc_datetime_usec
+
+    attribute :username, :string do
+      public? true
+
+      constraints match: ~r/^[a-zA-Z0-9_]+$/,
+                  min_length: 3,
+                  max_length: 30
+    end
+
+    attribute :display_name, :string do
+      public? true
+      constraints max_length: 50
+    end
+
+    attribute :avatar_url, :string do
+      public? true
+    end
   end
 
   relationships do
@@ -350,5 +434,6 @@ defmodule Mixer.Accounts.User do
 
   identities do
     identity :unique_email, [:email]
+    identity :unique_username, [:username], nils_distinct?: true
   end
 end
diff --git a/lib/mixer/posts/tweet.ex b/lib/mixer/posts/tweet.ex
index 9182416..13f10dd 100644
--- a/lib/mixer/posts/tweet.ex
+++ b/lib/mixer/posts/tweet.ex
@@ -254,6 +254,18 @@ defmodule Mixer.Posts.Tweet do
     calculate :user_email, :string, expr(user.email) do
       public? true
     end
+
+    calculate :user_username, :string, expr(user.username) do
+      public? true
+    end
+
+    calculate :user_display_name, :string, expr(user.display_name) do
+      public? true
+    end
+
+    calculate :user_avatar_url, :string, expr(user.avatar_url) do
+      public? true
+    end
   end
 
   aggregates do
diff --git a/lib/mixer_web/auth_overrides.ex b/lib/mixer_web/auth_overrides.ex
index abcb7d3..aafea61 100644
--- a/lib/mixer_web/auth_overrides.ex
+++ b/lib/mixer_web/auth_overrides.ex
@@ -15,4 +15,9 @@ defmodule MixerWeb.AuthOverrides do
     set :text, "⬡ Mixer"
     set :text_class, "text-3xl font-bold tracking-tight"
   end
+
+  # Inject the username field into the password registration form
+  override AshAuthentication.Phoenix.Components.Password do
+    set :register_extra_component, &MixerWeb.AuthComponents.username_register_field/1
+  end
 end
diff --git a/lib/mixer_web/components/auth_components.ex b/lib/mixer_web/components/auth_components.ex
new file mode 100644
index 0000000..dbc93b1
--- /dev/null
+++ b/lib/mixer_web/components/auth_components.ex
@@ -0,0 +1,51 @@
+defmodule MixerWeb.AuthComponents do
+  @moduledoc """
+  Extra components injected into AshAuthentication.Phoenix forms.
+  """
+
+  use Phoenix.Component
+
+  @doc """
+  Renders a username input field inside the password registration form.
+
+  Receives `form` (an `AshPhoenix.Form`) as an assign via the
+  `register_extra_component` override.
+  """
+  def username_register_field(assigns) do
+    field = assigns.form[:username]
+
+    assigns =
+      assigns
+      |> assign(:field_id, field.id)
+      |> assign(:field_name, field.name)
+      |> assign(:field_value, field.value || "")
+      |> assign(:field_errors, field.errors)
+
+    ~H"""
+    <div class="mt-2 mb-2">
+      <label for={@field_id} class="block text-sm font-medium text-base-content mb-1">
+        Username
+      </label>
+      <div class="flex">
+        <span class="input rounded-r-none border-r-0 text-base-content/50 select-none">@</span>
+        <input
+          type="text"
+          id={@field_id}
+          name={@field_name}
+          value={@field_value}
+          class={"input w-full rounded-l-none #{if @field_errors != [], do: "input-error", else: ""}"}
+          placeholder="your_handle"
+          autocomplete="username"
+          required
+        />
+      </div>
+      <p :if={@field_errors != []} class="mt-1 text-xs text-error">
+        {@field_errors |> List.first() |> elem(0)}
+      </p>
+      <p :if={@field_errors == []} class="mt-1 text-xs text-base-content/50">
+        3–30 characters · letters, numbers, underscores
+      </p>
+    </div>
+    """
+  end
+end
diff --git a/lib/mixer_web/controllers/page_html/index.html.heex b/lib/mixer_web/controllers/page_html/index.html.heex
index 96badd5..58118ae 100644
--- a/lib/mixer_web/controllers/page_html/index.html.heex
+++ b/lib/mixer_web/controllers/page_html/index.html.heex
@@ -2,6 +2,11 @@
   id="app"
   data-current-user-id={if @current_user, do: @current_user.id, else: ""}
   data-current-user-email={if @current_user, do: @current_user.email, else: ""}
+  data-current-user-username={if @current_user, do: @current_user.username || "", else: ""}
+  data-current-user-display-name={
+    if @current_user, do: @current_user.display_name || "", else: ""
+  }
+  data-current-user-avatar-url={if @current_user, do: @current_user.avatar_url || "", else: ""}
   data-asset-host={@media_host}
   data-page={@page}
   data-tweet-id={@tweet_id || ""}
diff --git a/lib/mixer_web/controllers/upload_controller.ex b/lib/mixer_web/controllers/upload_controller.ex
index adbae75..5ee7c41 100644
--- a/lib/mixer_web/controllers/upload_controller.ex
+++ b/lib/mixer_web/controllers/upload_controller.ex
@@ -2,6 +2,7 @@ defmodule MixerWeb.UploadController do
   use MixerWeb, :controller
 
   alias Mixer.Posts.MediaUploader
+  alias Mixer.Accounts.AvatarUploader
 
   def create(conn, %{"file" => %Plug.Upload{} = upload}) do
     actor = conn.assigns[:current_user]
@@ -46,4 +47,48 @@ defmodule MixerWeb.UploadController do
     |> put_status(:bad_request)
     |> json(%{error: "no file provided"})
   end
+
+  # ── Avatar upload ──────────────────────────────────────────────────────────
+
+  def upload_avatar(conn, %{"file" => %Plug.Upload{} = upload}) do
+    actor = conn.assigns[:current_user]
+
+    unless actor do
+      conn
+      |> put_status(:unauthorized)
+      |> json(%{error: "authentication required"})
+    else
+      scope = %{user_id: actor.id}
+
+      case AvatarUploader.store({upload, scope}) do
+        {:ok, _file_name} ->
+          # The thumb is always stored as avatars/:user_id/thumb.webp
+          thumb_key = "avatars/#{actor.id}/thumb.webp"
+
+          actor
+          |> Ash.Changeset.for_update(:update_avatar, %{avatar_url: thumb_key}, actor: actor)
+          |> Ash.update()
+          |> case do
+            {:ok, _user} ->
+              json(conn, %{success: true, avatarUrl: thumb_key})
+
+            {:error, error} ->
+              conn
+              |> put_status(:unprocessable_entity)
+              |> json(%{success: false, error: inspect(error)})
+          end
+
+        {:error, reason} ->
+          conn
+          |> put_status(:unprocessable_entity)
+          |> json(%{success: false, error: reason})
+      end
+    end
+  end
+
+  def upload_avatar(conn, _params) do
+    conn
+    |> put_status(:bad_request)
+    |> json(%{error: "no file provided"})
+  end
 end
diff --git a/lib/mixer_web/live/magic_sign_in_live.ex b/lib/mixer_web/live/magic_sign_in_live.ex
new file mode 100644
index 0000000..8be8ae8
--- /dev/null
+++ b/lib/mixer_web/live/magic_sign_in_live.ex
@@ -0,0 +1,184 @@
+defmodule MixerWeb.MagicSignInLive do
+  @moduledoc """
+  Custom magic-link sign-in LiveView that collects a username for new users.
+
+  When a user clicks their magic link, this page is shown instead of the
+  default auto-submit. If the user is brand new (no account) or has no
+  username set yet, we ask them to choose one before completing sign-in.
+  """
+
+  use AshAuthentication.Phoenix.Overrides.Overridable,
+    root_class: "CSS class for the root `div` element.",
+    magic_sign_in_id: "Element ID for the `MagicSignIn` LiveComponent."
+
+  use AshAuthentication.Phoenix.Web, :live_view
+
+  alias AshAuthentication.Info
+  alias AshPhoenix.Form
+  alias Phoenix.LiveView.{Rendered, Socket}
+
+  import AshAuthentication.Phoenix.Components.Helpers, only: [auth_path: 5]
+  import PhoenixHTMLHelpers.Form, only: [hidden_input: 3, submit: 2]
+  import Slug
+
+  @doc false
+  @impl true
+  def mount(params, session, socket) do
+    overrides =
+      session
+      |> Map.get("overrides", [AshAuthentication.Phoenix.Overrides.Default])
+
+    resource = session["resource"]
+    strategy_name = session["strategy"]
+    token = params["token"] || params["magic_link"]
+
+    strategy = Info.strategy!(resource, strategy_name)
+    subject_name = Info.authentication_subject_name!(resource)
+    domain = Info.authentication_domain!(resource)
+
+    # Determine whether this user needs to pick a username
+    needs_username? = needs_username?(token, resource)
+
+    form =
+      resource
+      |> Form.for_action(strategy.sign_in_action_name,
+        domain: domain,
+        as: subject_name |> to_string(),
+        id: "#{subject_name}-#{strategy_name}-sign-in-form" |> slugify(),
+        context: %{strategy: strategy, private: %{ash_authentication?: true}}
+      )
+
+    socket =
+      socket
+      |> assign(overrides: overrides)
+      |> assign(:token, token)
+      |> assign(:strategy, strategy)
+      |> assign(:subject_name, subject_name)
+      |> assign(:resource, resource)
+      |> assign(:needs_username?, needs_username?)
+      |> assign(:form, form)
+      |> assign(:trigger_action, false)
+      |> assign(:current_tenant, session["tenant"])
+      |> assign(:auth_routes_prefix, session["auth_routes_prefix"])
+
+    {:ok, socket}
+  end
+
+  @doc false
+  @impl true
+  @spec handle_params(map, String.t(), Socket.t()) :: {:noreply, Socket.t()}
+  def handle_params(_params, _uri, socket), do: {:noreply, socket}
+
+  @doc false
+  @impl true
+  @spec render(Socket.assigns()) :: Rendered.t()
+  def render(assigns) do
+    ~H"""
+    <div class={override_for(@overrides, :root_class)}>
+      <.live_component
+        module={AshAuthentication.Phoenix.Components.Banner}
+        id="magic-sign-in-banner"
+        overrides={@overrides}
+      />
+
+      <div style="max-width: 400px; margin: 0 auto; padding: 1rem;">
+        <.form
+          :let={form}
+          for={@form}
+          phx-submit="submit"
+          phx-trigger-action={@trigger_action}
+          action={
+            auth_path(
+              @socket,
+              @subject_name,
+              @auth_routes_prefix,
+              @strategy,
+              :sign_in
+            )
+          }
+          method="POST"
+        >
+          {hidden_input(form, :token, value: @token)}
+
+          <%!-- Username field — only shown for new or username-less users --%>
+          <div :if={@needs_username?} class="mt-2 mb-4">
+            <label
+              for={form[:username].id}
+              class="block text-sm font-medium text-base-content mb-1"
+            >
+              Choose a username
+            </label>
+            <div class="flex">
+              <span class="input rounded-r-none border-r-0 text-base-content/50 select-none">
+                @
+              </span>
+              <input
+                type="text"
+                id={form[:username].id}
+                name={form[:username].name}
+                value={form[:username].value || ""}
+                class={"input w-full rounded-l-none #{if form[:username].errors != [], do: "input-error", else: ""}"}
+                placeholder="your_handle"
+                autocomplete="username"
+                required
+              />
+            </div>
+            <p
+              :if={form[:username].errors != []}
+              class="mt-1 text-xs text-error"
+            >
+              {form[:username].errors |> List.first() |> elem(0)}
+            </p>
+            <p :if={form[:username].errors == []} class="mt-1 text-xs text-base-content/50">
+              3–30 characters · letters, numbers, underscores
+            </p>
+          </div>
+
+          {submit("Sign in",
+            class: "btn btn-primary w-full mt-2",
+            phx_disable_with: "Signing in…"
+          )}
+        </.form>
+      </div>
+    </div>
+    """
+  end
+
+  @doc false
+  @impl true
+  @spec handle_event(String.t(), map(), Socket.t()) :: {:noreply, Socket.t()}
+  def handle_event("submit", params, socket) do
+    subject_name =
+      socket.assigns.subject_name
+      |> to_string()
+      |> slugify()
+
+    form_params = Map.get(params, subject_name, %{})
+
+    form = Form.validate(socket.assigns.form, form_params)
+
+    socket =
+      socket
+      |> assign(:form, form)
+      |> assign(:trigger_action, form.valid?)
+
+    {:noreply, socket}
+  end
+
+  # ── Helpers ──────────────────────────────────────────────────────────────────
+
+  # Returns true if the user is new or has no username set yet.
+  defp needs_username?(nil, _resource), do: true
+
+  defp needs_username?(token, resource) do
+    with {:ok, claims} <- AshAuthentication.Jwt.peek(token),
+         subject when is_binary(subject) <- Map.get(claims, "sub"),
+         {:ok, user} <- AshAuthentication.subject_to_user(subject, resource) do
+      is_nil(user.username)
+    else
+      _ ->
+        # Unknown / new user — ask for username to be safe
+        true
+    end
+  end
+end
diff --git a/lib/mixer_web/router.ex b/lib/mixer_web/router.ex
index cb982b3..368b50a 100644
--- a/lib/mixer_web/router.ex
+++ b/lib/mixer_web/router.ex
@@ -47,6 +47,7 @@ defmodule MixerWeb.Router do
     post "/rpc/run", AshTypescriptRpcController, :run
     post "/rpc/validate", AshTypescriptRpcController, :validate
     post "/upload", UploadController, :create
+    post "/upload/avatar", UploadController, :upload_avatar
     auth_routes AuthController, Mixer.Accounts.User, path: "/auth"
     sign_out_route AuthController
 
@@ -74,6 +75,7 @@ defmodule MixerWeb.Router do
 
     # Remove this if you do not use the magic link strategy.
     magic_sign_in_route(Mixer.Accounts.User, :magic_link,
+      live_view: MixerWeb.MagicSignInLive,
       auth_routes_prefix: "/auth",
       overrides: [MixerWeb.AuthOverrides, Elixir.AshAuthentication.Phoenix.Overrides.DaisyUI]
     )
diff --git a/priv/repo/migrations/20260408035350_add_user_profile_fields.exs b/priv/repo/migrations/20260408035350_add_user_profile_fields.exs
new file mode 100644
index 0000000..8d43622
--- /dev/null
+++ b/priv/repo/migrations/20260408035350_add_user_profile_fields.exs
@@ -0,0 +1,29 @@
+defmodule Mixer.Repo.Migrations.AddUserProfileFields do
+  @moduledoc """
+  Updates resources based on their most recent snapshots.
+
+  This file was autogenerated with `mix ash_postgres.generate_migrations`
+  """
+
+  use Ecto.Migration
+
+  def up do
+    alter table(:users) do
+      add :username, :text
+      add :display_name, :text
+      add :avatar_url, :text
+    end
+
+    create unique_index(:users, [:username], name: "users_unique_username_index")
+  end
+
+  def down do
+    drop_if_exists unique_index(:users, [:username], name: "users_unique_username_index")
+
+    alter table(:users) do
+      remove :avatar_url
+      remove :display_name
+      remove :username
+    end
+  end
+end
diff --git a/priv/resource_snapshots/repo/users/20260408035351.json b/priv/resource_snapshots/repo/users/20260408035351.json
new file mode 100644
index 0000000..959d3bb
--- /dev/null
+++ b/priv/resource_snapshots/repo/users/20260408035351.json
@@ -0,0 +1,133 @@
+{
+  "attributes": [
+    {
+      "allow_nil?": false,
+      "default": "fragment(\"gen_random_uuid()\")",
+      "generated?": false,
+      "precision": null,
+      "primary_key?": true,
+      "references": null,
+      "scale": null,
+      "size": null,
+      "source": "id",
+      "type": "uuid"
+    },
+    {
+      "allow_nil?": false,
+      "default": "nil",
+      "generated?": false,
+      "precision": null,
+      "primary_key?": false,
+      "references": null,
+      "scale": null,
+      "size": null,
+      "source": "email",
+      "type": "citext"
+    },
+    {
+      "allow_nil?": true,
+      "default": "nil",
+      "generated?": false,
+      "precision": null,
+      "primary_key?": false,
+      "references": null,
+      "scale": null,
+      "size": null,
+      "source": "hashed_password",
+      "type": "text"
+    },
+    {
+      "allow_nil?": true,
+      "default": "nil",
+      "generated?": false,
+      "precision": null,
+      "primary_key?": false,
+      "references": null,
+      "scale": null,
+      "size": null,
+      "source": "confirmed_at",
+      "type": "utc_datetime_usec"
+    },
+    {
+      "allow_nil?": true,
+      "default": "nil",
+      "generated?": false,
+      "precision": null,
+      "primary_key?": false,
+      "references": null,
+      "scale": null,
+      "size": null,
+      "source": "username",
+      "type": "text"
+    },
+    {
+      "allow_nil?": true,
+      "default": "nil",
+      "generated?": false,
+      "precision": null,
+      "primary_key?": false,
+      "references": null,
+      "scale": null,
+      "size": null,
+      "source": "display_name",
+      "type": "text"
+    },
+    {
+      "allow_nil?": true,
+      "default": "nil",
+      "generated?": false,
+      "precision": null,
+      "primary_key?": false,
+      "references": null,
+      "scale": null,
+      "size": null,
+      "source": "avatar_url",
+      "type": "text"
+    }
+  ],
+  "base_filter": null,
+  "check_constraints": [],
+  "create_table_options": null,
+  "custom_indexes": [],
+  "custom_statements": [],
+  "has_create_action": true,
+  "hash": "E57BFA1141A2F4D237E6B3C8FE4BAD93772015179B56AEC9FA1F762C4FF5B6B8",
+  "identities": [
+    {
+      "all_tenants?": false,
+      "base_filter": null,
+      "index_name": "users_unique_email_index",
+      "keys": [
+        {
+          "type": "atom",
+          "value": "email"
+        }
+      ],
+      "name": "unique_email",
+      "nils_distinct?": true,
+      "where": null
+    },
+    {
+      "all_tenants?": false,
+      "base_filter": null,
+      "index_name": "users_unique_username_index",
+      "keys": [
+        {
+          "type": "atom",
+          "value": "username"
+        }
+      ],
+      "name": "unique_username",
+      "nils_distinct?": true,
+      "where": null
+    }
+  ],
+  "multitenancy": {
+    "attribute": null,
+    "global": null,
+    "strategy": null
+  },
+  "repo": "Elixir.Mixer.Repo",
+  "schema": null,
+  "table": "users"
+}
\ No newline at end of file
diff --git a/test/mixer/posts/tweet_like_test.exs b/test/mixer/posts/tweet_like_test.exs
index a42c7b8..b2d84ae 100644
--- a/test/mixer/posts/tweet_like_test.exs
+++ b/test/mixer/posts/tweet_like_test.exs
@@ -93,11 +93,15 @@ defmodule Mixer.Posts.TweetLikeTest do
   end
 
   defp user_fixture(email) do
+    username =
+      email |> String.split("@") |> List.first() |> String.replace(~r/[^a-zA-Z0-9_]/, "_")
+
     User
     |> Ash.Changeset.for_create(:register_with_password, %{
       email: email,
       password: "password1234",
-      password_confirmation: "password1234"
+      password_confirmation: "password1234",
+      username: username
     })
     |> Ash.create!()
   end
diff --git a/test/mixer_web/controllers/page_controller_test.exs b/test/mixer_web/controllers/page_controller_test.exs
index 5d45018..23128cc 100644
--- a/test/mixer_web/controllers/page_controller_test.exs
+++ b/test/mixer_web/controllers/page_controller_test.exs
@@ -9,7 +9,8 @@ defmodule MixerWeb.PageControllerTest do
         %{
           email: "test@example.com",
           password: "Password1!",
-          password_confirmation: "Password1!"
+          password_confirmation: "Password1!",
+          username: "testuser"
         },
         authorize?: false
       )