Convex Authentication - Core Patterns

This skill covers universal auth patterns that work with ANY authentication provider.

Auth in Functions

Access the authenticated user via ctx.auth.getUserIdentity():

import { query, mutation, action } from './_generated/server';

export const myQuery = query({
  args: {},
  handler: async (ctx) => {
    const identity = await ctx.auth.getUserIdentity();
    if (identity === null) {
      throw new Error('Not authenticated');
    }
    // identity.tokenIdentifier - unique across providers
    // identity.subject - user ID from provider
    // identity.email, identity.name, etc. (if configured)
  }
});

UserIdentity Fields

Critical: Race Condition Prevention

Problem: Queries can execute before auth is validated on page load.

Client-side: Always use useConvexAuth() from convex/react, NOT your provider's hook:

// ✅ Correct - waits for Convex to validate token
import { useConvexAuth } from 'convex/react';
const { isLoading, isAuthenticated } = useConvexAuth();

// ❌ Wrong - only checks provider, not Convex validation
const { isSignedIn } = useAuth(); // from @clerk/clerk-react

Skip queries until authenticated:

const user = useQuery(api.users.current, isAuthenticated ? {} : 'skip');

Use Convex auth components:

import { Authenticated, Unauthenticated, AuthLoading } from "convex/react";

<Authenticated>
  <Content /> {/* Queries here are safe */}
</Authenticated>
<Unauthenticated>
  <SignInButton />
</Unauthenticated>

Storing Users in Database

See USERS.md for complete patterns including:

• Schema design with indexes
• Storing users via client mutation
• Storing users via webhooks (recommended for production)
• Helper functions for user lookup

Custom Auth Wrappers

Create authenticated function wrappers using convex-helpers:

// convex/lib/auth.ts
import {
  query,
  mutation,
  action,
  QueryCtx,
  MutationCtx,
  ActionCtx
} from './_generated/server';
import {
  customQuery,
  customMutation,
  customAction,
  customCtx
} from 'convex-helpers/server/customFunctions';
import { ConvexError } from 'convex/values';

async function requireAuth(ctx: QueryCtx | MutationCtx | ActionCtx) {
  const identity = await ctx.auth.getUserIdentity();
  if (!identity) {
    throw new ConvexError('Not authenticated');
  }
  return identity;
}

export const authQuery = customQuery(
  query,
  customCtx(async (ctx) => {
    const identity = await requireAuth(ctx);
    return { identity };
  })
);

export const authMutation = customMutation(
  mutation,
  customCtx(async (ctx) => {
    const identity = await requireAuth(ctx);
    return { identity };
  })
);

export const authAction = customAction(
  action,
  customCtx(async (ctx) => {
    const identity = await requireAuth(ctx);
    return { identity };
  })
);

Usage:

import { authQuery } from './lib/auth';

export const myProtectedQuery = authQuery({
  args: {},
  handler: async (ctx) => {
    // ctx.identity is guaranteed to exist
    const userId = ctx.identity.subject;
  }
});

HTTP Actions with Auth

Pass JWT in Authorization header:

// Client
fetch('https://your-deployment.convex.site/api/endpoint', {
  headers: { Authorization: `Bearer ${jwtToken}` }
});

// convex/http.ts
import { httpAction } from './_generated/server';

export const myEndpoint = httpAction(async (ctx, request) => {
  const identity = await ctx.auth.getUserIdentity();
  if (!identity) {
    return new Response('Unauthorized', { status: 401 });
  }
  // ...
});

Debugging Checklist

See DEBUG.md for detailed troubleshooting steps.

Quick checks:

1. ctx.auth.getUserIdentity() returns null?
   • Check if query runs before auth completes (use "skip" pattern)
   • Check auth.config.ts is deployed (npx convex dev)
2. Check Settings > Authentication in Convex Dashboard
3. Verify JWT token at https://jwt.io - check iss and aud fields
4. Ensure domain in auth.config.ts matches JWT iss
5. Ensure applicationID matches JWT aud

DO ✅

• Always check ctx.auth.getUserIdentity() in public functions
• Use useConvexAuth() hook, not provider's auth hook
• Skip queries with "skip" until authenticated
• Use <Authenticated> component to gate protected content
• Store users in DB for cross-user queries
• Use tokenIdentifier or subject as unique user key

DON'T ❌

• Trust client-side auth alone (Convex is a public API)
• Run queries before checking isAuthenticated
• Use .filter() to find users by token (use index)
• Assume identity fields exist (check provider config)
• Forget to redeploy after changing auth.config.ts