diff --git a/src/app/api/auth/reset-password/route.ts b/src/app/api/auth/reset-password/route.ts
index fe6d680..9b1105f 100644
--- a/src/app/api/auth/reset-password/route.ts
+++ b/src/app/api/auth/reset-password/route.ts
@@ -1,5 +1,5 @@
 import { NextResponse } from "next/server";
-import { createHash, randomBytes, scryptSync } from "crypto";
+import { createHash } from "crypto";
 import { getServiceSupabase } from "@/lib/supabase/client";
 
 export const runtime = "nodejs";
@@ -8,12 +8,6 @@ function hashToken(token: string): string {
   return createHash("sha256").update(token).digest("hex");
 }
 
-function hashPassword(password: string, salt?: string): string {
-  const safeSalt = salt || randomBytes(16).toString("hex");
-  const derived = scryptSync(password, safeSalt, 64).toString("hex");
-  return `scrypt$${safeSalt}$${derived}`;
-}
-
 export async function POST(request: Request) {
   try {
     const body = (await request.json()) as {
@@ -47,7 +41,7 @@ export async function POST(request: Request) {
     // Find valid token with user info
     const { data: resetToken } = await supabase
       .from("password_reset_tokens")
-      .select("id, user_id, users(email)")
+      .select("id, user_id, users(email, name)")
       .eq("token_hash", tokenHash)
       .eq("used", false)
       .gt("expires_at", now)
@@ -64,22 +58,36 @@ export async function POST(request: Request) {
     const userEmail = Array.isArray(resetToken.users)
       ? resetToken.users[0]?.email
       : resetToken.users?.email;
+    const userName = Array.isArray(resetToken.users)
+      ? resetToken.users[0]?.name
+      : resetToken.users?.name;
 
     if (userEmail?.toLowerCase() !== email) {
       return NextResponse.json({ error: "Invalid reset token" }, { status: 400 });
     }
 
-    // Hash new password
-    const passwordHash = hashPassword(password);
-
-    // Update user password
-    const { error: updateError } = await supabase
-      .from("users")
-      .update({ password_hash: passwordHash })
-      .eq("id", resetToken.user_id);
+    // Update Supabase Auth password. If auth user doesn't exist yet (legacy migration),
+    // create it with the same UUID so app foreign keys remain valid.
+    const { error: updateError } = await supabase.auth.admin.updateUserById(resetToken.user_id, {
+      password,
+    });
 
     if (updateError) {
-      throw updateError;
+      const updateMessage = updateError.message || "";
+      if (updateMessage.toLowerCase().includes("not found")) {
+        const { error: createError } = await supabase.auth.admin.createUser({
+          id: resetToken.user_id,
+          email,
+          password,
+          email_confirm: true,
+          user_metadata: {
+            name: typeof userName === "string" && userName.trim().length > 0 ? userName : undefined,
+          },
+        });
+        if (createError) throw createError;
+      } else {
+        throw updateError;
+      }
     }
 
     // Mark token as used
diff --git a/src/lib/server/auth.ts b/src/lib/server/auth.ts
index 40e1c08..f74be37 100644
--- a/src/lib/server/auth.ts
+++ b/src/lib/server/auth.ts
@@ -1,6 +1,8 @@
-import { randomBytes, scryptSync, timingSafeEqual, createHash } from "crypto";
+import { randomBytes, createHash } from "crypto";
 import { cookies } from "next/headers";
+import { createClient } from "@supabase/supabase-js";
 import { getServiceSupabase } from "@/lib/supabase/client";
+import type { Database } from "@/lib/supabase/database.types";
 
 const SESSION_COOKIE_NAME = "gantt_session";
 const SESSION_HOURS_SHORT = 12;
@@ -19,10 +21,24 @@ interface UserRow {
   name: string;
   email: string;
   avatar_url: string | null;
-  password_hash: string;
   created_at: string;
 }
 
+function getPublicSupabase() {
+  const supabaseUrl = process.env.NEXT_PUBLIC_SUPABASE_URL;
+  const supabaseAnonKey = process.env.NEXT_PUBLIC_SUPABASE_ANON_KEY;
+  if (!supabaseUrl || !supabaseAnonKey) {
+    throw new Error("Missing Supabase public environment variables");
+  }
+
+  return createClient<Database>(supabaseUrl, supabaseAnonKey, {
+    auth: {
+      autoRefreshToken: false,
+      persistSession: false,
+    },
+  });
+}
+
 function normalizeEmail(email: string): string {
   return email.trim().toLowerCase();
 }
@@ -40,22 +56,11 @@ function normalizeAvatarUrl(value: string | null | undefined): string | undefine
   return trimmed;
 }
 
-function hashPassword(password: string, salt?: string): string {
-  const safeSalt = salt || randomBytes(16).toString("hex");
-  const derived = scryptSync(password, safeSalt, 64).toString("hex");
-  return `scrypt$${safeSalt}$${derived}`;
-}
-
-function verifyPassword(password: string, stored: string): boolean {
-  const parts = stored.split("$");
-  if (parts.length !== 3 || parts[0] !== "scrypt") return false;
-  const [, salt, digest] = parts;
-  const candidate = hashPassword(password, salt);
-  const candidateDigest = candidate.split("$")[2];
-  const a = Buffer.from(digest, "hex");
-  const b = Buffer.from(candidateDigest, "hex");
-  if (a.length !== b.length) return false;
-  return timingSafeEqual(a, b);
+function fallbackNameFromEmail(email: string, preferredName?: string | null): string {
+  const trimmed = (preferredName || "").trim();
+  if (trimmed.length >= 2) return trimmed;
+  const base = email.split("@")[0]?.trim() || "User";
+  return base.length >= 2 ? base : "User";
 }
 
 function hashSessionToken(token: string): string {
@@ -84,6 +89,42 @@ function mapUserRow(row: UserRow): AuthUser {
   };
 }
 
+async function upsertUserMirrors(params: {
+  id: string;
+  name: string;
+  email: string;
+  avatarUrl?: string | null;
+}) {
+  const supabase = getServiceSupabase();
+  const { error: userError } = await supabase.from("users").upsert(
+    {
+      id: params.id,
+      name: params.name,
+      email: normalizeEmail(params.email),
+      avatar_url: params.avatarUrl ?? null,
+    },
+    { onConflict: "id" }
+  );
+
+  if (userError) {
+    throw new Error(userError.message || "Failed to sync user profile");
+  }
+
+  const { error: profileError } = await supabase.from("profiles").upsert(
+    {
+      id: params.id,
+      name: params.name,
+      avatar_url: params.avatarUrl ?? null,
+      updated_at: new Date().toISOString(),
+    },
+    { onConflict: "id" }
+  );
+
+  if (profileError) {
+    console.error("Failed to sync profiles mirror:", profileError.message);
+  }
+}
+
 export async function registerUser(params: {
   name: string;
   email: string;
@@ -100,34 +141,41 @@ export async function registerUser(params: {
   if (password.length < 8) throw new Error("Password must be at least 8 characters");
 
   const supabase = getServiceSupabase();
+  const { data, error } = await supabase.auth.admin.createUser({
+    email,
+    password,
+    email_confirm: true,
+    user_metadata: { name },
+  });
 
-  // Check if email already exists
-  const { data: existing } = await supabase
-    .from("users")
-    .select("id")
-    .eq("email", email)
-    .maybeSingle();
-
-  if (existing) {
-    throw new Error("Email already exists");
+  if (error || !data.user) {
+    const message = error?.message || "Failed to create user";
+    if (message.toLowerCase().includes("already")) {
+      throw new Error("Email already exists");
+    }
+    throw new Error(message);
   }
 
-  // Create user
-  const { data: user, error } = await supabase
+  const authUser = data.user;
+  const userName = fallbackNameFromEmail(email, name);
+  await upsertUserMirrors({
+    id: authUser.id,
+    name: userName,
+    email,
+    avatarUrl: null,
+  });
+
+  const { data: userRow, error: userError } = await supabase
     .from("users")
-    .insert({
-      name,
-      email,
-      password_hash: hashPassword(password),
-    })
     .select("id, name, email, avatar_url, created_at")
+    .eq("id", authUser.id)
     .single();
 
-  if (error || !user) {
-    throw new Error(error?.message || "Failed to create user");
+  if (userError || !userRow) {
+    throw new Error(userError?.message || "Failed to load user profile");
   }
 
-  return mapUserRow(user as UserRow);
+  return mapUserRow(userRow as UserRow);
 }
 
 export async function authenticateUser(params: {
@@ -137,16 +185,42 @@ export async function authenticateUser(params: {
   await deleteExpiredSessions();
 
   const email = normalizeEmail(params.email);
+  const authClient = getPublicSupabase();
+  const { data: signInData, error: signInError } = await authClient.auth.signInWithPassword({
+    email,
+    password: params.password,
+  });
+
+  if (signInError || !signInData.user) return null;
+
   const supabase = getServiceSupabase();
+  const authUser = signInData.user;
+
+  const { data: existingRow } = await supabase
+    .from("users")
+    .select("id, name, email, avatar_url, created_at")
+    .eq("id", authUser.id)
+    .maybeSingle();
+
+  const userName = fallbackNameFromEmail(
+    authUser.email || email,
+    typeof authUser.user_metadata?.name === "string" ? authUser.user_metadata.name : existingRow?.name
+  );
+
+  await upsertUserMirrors({
+    id: authUser.id,
+    name: userName,
+    email: authUser.email || email,
+    avatarUrl: existingRow?.avatar_url || null,
+  });
 
   const { data: row } = await supabase
     .from("users")
-    .select("id, name, email, avatar_url, password_hash, created_at")
-    .eq("email", email)
+    .select("id, name, email, avatar_url, created_at")
+    .eq("id", authUser.id)
     .maybeSingle();
 
   if (!row) return null;
-  if (!verifyPassword(params.password, row.password_hash)) return null;
 
   return mapUserRow(row as UserRow);
 }
@@ -166,7 +240,7 @@ export async function updateUserAccount(params: {
   // Get current user data
   const { data: row } = await supabase
     .from("users")
-    .select("id, name, email, avatar_url, password_hash, created_at")
+    .select("id, name, email, avatar_url, created_at")
     .eq("id", params.userId)
     .single();
 
@@ -189,7 +263,12 @@ export async function updateUserAccount(params: {
 
   if (needsPasswordCheck) {
     if (!currentPassword) throw new Error("Current password is required");
-    if (!verifyPassword(currentPassword, row.password_hash)) {
+    const authClient = getPublicSupabase();
+    const { error: authError } = await authClient.auth.signInWithPassword({
+      email: row.email,
+      password: currentPassword,
+    });
+    if (authError) {
       throw new Error("Current password is incorrect");
     }
   }
@@ -205,7 +284,27 @@ export async function updateUserAccount(params: {
     if (existing) throw new Error("Email already exists");
   }
 
-  const nextPasswordHash = passwordChanged ? hashPassword(newPassword) : row.password_hash;
+  if (emailChanged || passwordChanged || requestedName !== row.name) {
+    const updatePayload: {
+      email?: string;
+      password?: string;
+      user_metadata?: { name: string };
+    } = {
+      user_metadata: { name: requestedName },
+    };
+
+    if (emailChanged) updatePayload.email = requestedEmail;
+    if (passwordChanged) updatePayload.password = newPassword;
+
+    const { error: authUpdateError } = await supabase.auth.admin.updateUserById(row.id, updatePayload);
+    if (authUpdateError) {
+      const message = authUpdateError.message || "Failed to update account";
+      if (message.toLowerCase().includes("already")) {
+        throw new Error("Email already exists");
+      }
+      throw new Error(message);
+    }
+  }
 
   const { data: updated, error } = await supabase
     .from("users")
@@ -213,7 +312,6 @@ export async function updateUserAccount(params: {
       name: requestedName,
       email: requestedEmail,
       avatar_url: requestedAvatar ?? null,
-      password_hash: nextPasswordHash,
     })
     .eq("id", row.id)
     .select("id, name, email, avatar_url, created_at")
@@ -223,6 +321,20 @@ export async function updateUserAccount(params: {
     throw new Error(error?.message || "Failed to update user");
   }
 
+  const { error: profileError } = await supabase.from("profiles").upsert(
+    {
+      id: row.id,
+      name: requestedName,
+      avatar_url: requestedAvatar ?? null,
+      updated_at: new Date().toISOString(),
+    },
+    { onConflict: "id" }
+  );
+
+  if (profileError) {
+    console.error("Failed to sync profiles mirror:", profileError.message);
+  }
+
   return mapUserRow(updated as UserRow);
 }