Free API for Frontend Developers

You want to ship the UI today, not wait for a backend. Point your fetch / axios / React Query at this sandbox and build a real product flow — login, list, create, paginate, filter — without writing a single backend route.

What's in it for the frontend

• CORS open — call it directly from localhost or any origin
• Real login — a JWT you can store, attach as Bearer, and refresh
• Pagination + filtering — drive infinite-scroll and search UIs realistically
• Persistence — your POSTs persist for 30 minutes per session
• Error simulation — trigger 500s and timeouts to test your error UI

React + fetch

const res = await fetch('https://demo.totalshiftleft.ai/api/v1/users?page=1');
const { data } = await res.json();
setUsers(data.items);

React Query / TanStack Query

const { data, isPending } = useQuery({
  queryKey: ['users', page],
  queryFn: () => fetch(`/api/v1/users?page=${page}`).then(r => r.json())
});

Vue 3 (Composition API)

const users = ref([]);
onMounted(async () => {
  const r = await fetch('https://demo.totalshiftleft.ai/api/v1/users');
  users.value = (await r.json()).data.items;
});

SvelteKit (load function)

export async function load({ fetch }) {
  const r = await fetch('https://demo.totalshiftleft.ai/api/v1/users');
  return { users: (await r.json()).data.items };
}

Auth in 6 lines

const r = await fetch('https://demo.totalshiftleft.ai/auth/token', {
  method: 'POST',
  headers: { 'Content-Type': 'application/json' },
  body: JSON.stringify({ username: 'demo', password: 'demo' })
});
const { access_token } = await r.json();
localStorage.setItem('token', access_token);

Built for portfolio projects and hackathons

Build a clone of LinkedIn, Twitter, an e-commerce checkout, a Kanban board — all using real users, products, orders, posts and comments. Free, no API key, no backend setup. Need GraphQL instead? Same data, GraphQL endpoint.

Frequently asked questions

Will the data still be there tomorrow?

Per-session data expires after 30 minutes idle. Seed data resets nightly — perfect for demos, not for "real" persistence.

Is CORS open enough for localhost?

Yes — every origin is allowed for browser fetch. Credentials supported via session cookie too.

Other free public APIs in this sandbox

Topics: API for frontend developers · free API for React / Vue / Svelte · frontend prototype API · mock backend · API for portfolio projects