Authentication · decision tool
Which auth provider should I use?
Set your monthly active users and constraints — get a ranked auth verdict with the real bill at YOUR scale. Clerk, Better Auth, Auth0, Supabase, Kinde, WorkOS.
Prices verified 2026-07-15 against official pricing pages · fit weights are our estimates (see methodology) · share the URL to share your configuration
As of Jul 2026, with 5,000 monthly active users, a $50 budget for this slot, Clerk ranks first for these inputs at 96% fit and a StackSays-estimated $0/month (Auth0: 96% fit, $0/month). Fit weights are our estimates; prices trace to official pages. Change any input below and the verdict recomputes.
Your situation
The verdict updates as you move these.
Toss-up — your priorities decide, not the tools
Plug-and-play auth with the best prebuilt UI; you pay for the polish as you grow
vs Auth0: fit 96% against 96%, est $0 against $0 per month — genuinely close; read both risk lists below
The decision, in plain words
For a solo builder at 5,000 monthly active users and a $50.00/mo budget for the auth provider slot, Clerk leads at 96% fit and $0/mo. The two rules doing the work: budget fit (Runs free at your usage — $0 vs your $50/mo budget); batteries included (Bundles prebuilt sign-in UI, organizations/teams, enterprise SSO — fewer services to glue at team size 1).
Auth0 is a genuine coin-flip here (96% fit, $0/mo) — read both risk lists and pick the failure mode you prefer.
Honest weak spot of the pick: hosted user store — migrating away means a coordinated export (password hashes via support).
Generated from the calculation above — every number traces to the sourced data; nothing here is written by an AI making things up.
Why Clerk scores 96%
How the $0/mo estimate is calculated
Your usage fits Clerk's free tier (50,000 monthly retained users (MRU), full features) — the estimate is $0.
What could change this verdict
Cost risk
Official prices verified 2026-07-15; calculation is deterministic code over those prices.
At a glance
| Tool | Free tier | Paid entry | Verified |
|---|---|---|---|
| Clerk | 50,000 monthly retained users (MRU), full features | Pro $25/mo | 2026-07-15 |
| Better Auth | No free tier | — | 2026-07-15 |
| Auth0 | 25,000 MAU, no credit card | Essentials $35/mo | 2026-07-15 |
| Supabase Auth | 50,000 MAU on the Supabase free plan | Pro (platform) $25/mo | 2026-07-15 |
| Firebase Auth | 50,000 MAU at no charge | — | 2026-07-15 |
| Kinde | 10,500 MAU free forever | Pro $25/mo | 2026-07-15 |
| WorkOS | First 1,000,000 MAU free | — | 2026-07-15 |
Data sources
| Tool | Source | Verified |
|---|---|---|
| Clerk | Clerk pricing page | 2026-07-15 |
| Better Auth | Better Auth pricing page | 2026-07-15 |
| Auth0 | Auth0 pricing page | 2026-07-15 |
| Supabase Auth | Supabase pricing page | 2026-07-15 |
| Firebase Auth | Firebase pricing page | 2026-07-15 |
| Kinde | Kinde pricing page | 2026-07-15 |
| WorkOS | WorkOS pricing page | 2026-07-15 |
A monitor re-checks these pages for changes; when a vendor moves a price, the date updates and every verdict recomputes.
People also ask
Can I use Clerk for free?
Yes — up to 50,000 monthly retained users with full features (verified 2026-07-15). Note the metric: Clerk counts retained users (MRU), not raw MAU. The Pro plan is $25/mo and adds $0.02 per user beyond 50K — at 100K users that's ~$1,025/mo.
Can I use Auth0 for free?
Yes — the free tier covers 25,000 MAU with no credit card (verified 2026-07-15). The catch is what comes after: paid plans start at $35/mo for only 500 MAU and bill in tier jumps, so crossing the free ceiling is a real cliff.
Is Clerk worth it?
If shipping this week matters, usually yes below ~50K users (free tier). The math flips as you grow: at 100K retained users Clerk is ~$1,025/mo while Better Auth in your own Postgres is ~$0/user. The calculator above prices both at your exact scale.