StackBest authentication for solo founders
Every app needs login, and building it yourself means password resets, session security, and OAuth edge cases eating weeks you don't have. Auth providers solve that for a monthly fee that usually starts at zero but can quietly balloon once you cross a user threshold. The real comparison is not features, it is where the free tier ends and what each extra user costs after that.
| Tool | Free tier | Paid from | Best for |
|---|---|---|---|
 Clerk$25/mo | $25/mo | Next.js/React solo founders who want polished auth UI shipped today and are unlikely to pass 50k users soon | |
 Auth0$35/mo | $35/mo | Founders selling into enterprises who need the Auth0 brand name and protocol coverage, and who will stay under 25k MAUs for a while | |
 Supabase Auth$25/mo | $25/mo | Founders already on Supabase (like StackTracker's stack) who want auth, database, and storage on one $25 bill | |
 WorkOS$125/mo per enterprise SSO connection | $125/mo per enterprise SSO connection | Founders who want free auth at any realistic scale and only pay when an enterprise customer demands SSO | |
| $25/mo | Early B2B founders under 10k users who want auth, orgs, feature flags, and billing in one $0-25 tool | ||
 Better Auth (self-hosted)$0 | $0 | TypeScript-comfortable founders who want zero MAU costs and full data ownership, and accept owning the maintenance | |
 Firebase Authusage-based from $0.0055/MAU beyond 50k | usage-based from $0.0055/MAU beyond 50k | Mobile-first founders on iOS/Android who want free, reliable auth and do not need enterprise SSO |
If you are already on Supabase, use Supabase Auth: it is bundled at every tier, free plan included (50k MAUs at $0, 100k on Pro), and it keeps users in your own Postgres. Starting fresh on Next.js with no database preference, Clerk's free tier (50k retained users, prebuilt UI) is the fastest path to shipped, at $0 until you scale, then $25/mo.
If an enterprise customer demands SSO, add WorkOS ($125/mo per connection, billed to that customer) or switch to Better Auth to get SSO free at the cost of self-maintenance. Avoid Auth0 unless enterprise buyers require it: the jump from free to $700/mo at 10k MAUs is the worst cliff in the category.
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