Stack Auth vs Clerk for Solo Developers

Quick Comparison

Stack Auth Overview

Stack Auth is the open-source auth platform that gained serious traction over the past year as a Clerk alternative. The pitch is the same developer experience you'd expect from a modern managed auth provider, with the source code on GitHub and the option to self-host whenever you want. Email, OAuth, magic links, organizations, team management, and a hosted UI all included.

The managed version has a generous free tier and predictable pricing as you grow. The self-hosted version is the same product running on your infrastructure, with no feature gating or paid-only features. This matters because it means you can start on the managed version, then move to self-hosted if cost or compliance demands it, without changing your application code.

For solo developers, Stack Auth's appeal is owning your auth layer without writing it yourself. You get most of what Clerk offers, the bill is lower or zero, and if anything ever goes wrong with the company you can keep running on your own server.

Clerk Overview

Clerk is the polished, commercial managed auth provider that's been a default choice for Next.js and React developers for years. The pre-built React components handle sign-up, sign-in, user profile, and organization management with almost no work. Drop them in, configure your theme, and you have production auth in an afternoon.

Beyond the UI components, Clerk handles email, OAuth, MFA, sessions, organizations, RBAC, and webhooks. The dashboard is excellent. The docs are excellent. The support is responsive. For most teams, Clerk is the no-thinking-required answer to auth.

Clerk's free tier covers up to 50,000 monthly retained users, which it raised from 10,000 in early 2026, so it is genuinely generous for solo dev projects now. Beyond that, the Pro plan is $25/mo and includes 50,000 retained users, then $0.02 per user per month above that. For a hobby project, you will almost never pay. For a successful side project that takes off, the bill stays small until you cross 50,000 users, and then it grows linearly with each one.

Key Differences

The pricing model has different long-term implications. Clerk is free until you have real users, then it scales with success. Stack Auth's managed version is cheaper at scale, and the self-hosted version has no per-user fee at all. If you expect your project to grow large, the cost curve favors Stack Auth. If it'll never get past a few thousand users, Clerk's free tier covers you forever.

The polish gap is real but shrinking. Clerk's pre-built components are still the gold standard for drop-in auth UI. Stack Auth's hosted UI is good and improving, but Clerk's polish is hard to match. If you want the absolute fastest path from zero to production auth with a UI that looks great, Clerk is still ahead.

Self-hostability changes the conversation. Stack Auth being open source and self-hostable is the biggest differentiator. It means you can run your auth on your own infrastructure for compliance reasons, you're not locked into a vendor's pricing changes, and if the company ever folds you can keep running. Clerk gives you none of these guarantees.

Organizations and teams are well-supported on both. Both platforms handle organizations, roles, and team invitations cleanly. Clerk's implementation is more refined, with better default UI and more flexible permission systems. Stack Auth covers the common cases well and is improving fast.

Migration paths differ in important ways. Migrating away from Clerk means rewriting auth in your app, which is a serious project. Migrating Stack Auth managed to Stack Auth self-hosted is mostly a configuration change. The escape hatch matters more than people think, especially for solo devs who can't afford a multi-week auth rewrite later.

When to Choose Stack Auth

• You want the option to self-host your auth in the future
• You're cost-sensitive and don't want per-user pricing as you grow
• Open source matters to you for technical or philosophical reasons
• You're building something that might need compliance flexibility
• You want competitive features without vendor lock-in

When to Choose Clerk

• You want the most polished pre-built auth UI components available
• Your project is small enough that the free tier covers you indefinitely
• You value excellent docs, dashboard, and support
• You're building on Next.js or React and want the smoothest integration
• Speed of initial setup matters more than long-term cost or portability

The Verdict

For most solo developers in 2026, Clerk is still the easiest yes for a new project. The pre-built UI components save you a real week of work, the free tier covers any hobby project, and you can ship auth in an afternoon. If your project never gets huge, you'll never pay them anything.

Stack Auth is the right choice if you're playing the long game. If you expect the project to grow into a real business, or you care about being able to self-host later, or you want the cost curve to flatten instead of climb with users, Stack Auth is the better bet. The DX gap with Clerk is small enough now that you're not giving up much.

The real question is what kind of project you're building. For experiments and side projects that might never matter, use Clerk and move on. For anything where you might one day care about owning your auth infrastructure, start on Stack Auth from day one. Migrating later is more painful than choosing right the first time, and Stack Auth gives you both speed today and optionality tomorrow.

By the Numbers (2026)

These figures were pulled on 2026-05-29 from each project's package registry, GitHub, and pricing page. The contrast in adoption is the headline here, and the pricing contrast is the part that actually changes your decision.

Versions and release cadence. Stack Auth ships its React SDK as @stackframe/stack, latest v2.8.108, last published to npm on 2026-05-26. Clerk's Next.js SDK is @clerk/nextjs, latest v7.4.2, published on 2026-05-29. Both are actively maintained with recent releases, so neither is a stale bet.

Adoption. Clerk is the far more widely installed of the two. @clerk/nextjs pulled roughly 1,405,945 downloads in the week of 2026-05-22 to 2026-05-28, and about 5,762,151 in the trailing 30 days. @stackframe/stack pulled roughly 30,959 in the same week and about 115,956 over the trailing month. That is Clerk at roughly 45 to 50 times the weekly install volume. If a deep ecosystem of tutorials, Stack Overflow answers, and community plugins matters to you, Clerk's lead is real.

GitHub. The Stack Auth monorepo at stack-auth/stack-auth carries about 6,801 stars, 516 forks, and 27 open issues, created in February 2024, and it markets itself directly as an "Open-source Auth0/Clerk alternative." Clerk's open-source surface is its SDK monorepo at clerk/javascript with about 1,707 stars under an MIT license. Note that star counts are not apples to apples here. Stack Auth open-sources the entire auth platform, while Clerk only open-sources its client libraries and keeps the service itself closed.

Free tiers. Clerk's free plan now covers 50,000 monthly retained users per application, raised from 10,000 earlier in 2026. Stack Auth's managed free tier covers 10,000 users, and self-hosting is free with no user cap at all.

Paid entry. Clerk Pro is $25/mo ($20/mo billed annually) and already includes 50,000 retained users, with $0.02 per retained user per month after that. Stack Auth's first paid tier is Team at $49/mo, which lifts the user limit to 50,000, and Growth is $299/mo for unlimited users. Stack Auth does not publish a per-user overage rate, you move up a tier instead.

Real Cost at Solo-Dev Scale

Pricing here is not symmetric, so a worked example beats a vibe. Take a solo dev whose project crosses into a real audience: 60,000 active or retained users in a billing month. All rates below are from each vendor's published pricing page on 2026-05-29.

Clerk at 60,000 users. The Pro plan is $25/mo and includes the first 50,000 retained users. The remaining 10,000 are billed at $0.02 each, which is $200. Total: $25 + $200 = $225/mo.

Stack Auth at 60,000 users (managed). 60,000 exceeds the Team tier ceiling of 50,000 users, so a managed customer at this scale is on the Growth tier at $299/mo for unlimited users. Total: $299/mo flat, and it does not climb as users keep growing.

Stack Auth at 60,000 users (self-hosted). $0 in license fees. You pay only for the server you run it on, which for a single-region Postgres-backed deployment is realistically in the $20 to $40/mo range on a small VPS or managed database. Call it roughly $30/mo plus your own time to operate it.

So at 60,000 users the managed comparison is close ($225 Clerk vs $299 Stack Auth Growth), and Clerk is actually cheaper at this exact point because its per-user overage has not yet outrun a flat tier. The picture flips as you grow. Push to 200,000 users and Clerk's overage math is $25 + (150,000 x $0.02) = $3,025/mo, while Stack Auth Growth stays $299/mo managed or near-zero self-hosted. The crossover point is the whole argument. Below it, Clerk's generous 50,000-user free band and cheap Pro tier win. Above it, Stack Auth's flat tiers and free self-hosting pull away hard. For a project you genuinely expect to scale, the self-hosted escape hatch is the cheapest line on the page.

(Clerk bills on "monthly retained users" and Stack Auth on "users," which are not defined identically, so treat the comparison as directional rather than to-the-cent. Always check current pricing before committing.)

Sources

• Stack Auth pricing (Free 10K users, Team $49/mo for 50K, Growth $299/mo unlimited, self-host free): https://stack-auth.com/pricing (checked 2026-05-29)
• Clerk pricing (Free 50,000 MRU, Pro $25/mo incl 50K MRU then $0.02/MRU, Business $300/mo): https://clerk.com/pricing (checked 2026-05-29)
• Clerk free-tier increase to 50,000 users announcement: https://clerk.com/blog/new-pricing-plans (checked 2026-05-29)
• Stack Auth GitHub repo (stars, forks, issues, description, license): https://github.com/stack-auth/stack-auth (checked 2026-05-29)
• Clerk SDK GitHub monorepo (stars, MIT license): https://github.com/clerk/javascript (checked 2026-05-29)
• @stackframe/stack version on npm registry: https://registry.npmjs.org/@stackframe/stack (checked 2026-05-29)
• @clerk/nextjs version on npm registry: https://registry.npmjs.org/@clerk/nextjs (checked 2026-05-29)
• @stackframe/stack weekly download count: https://api.npmjs.org/downloads/point/last-week/@stackframe/stack (checked 2026-05-29)
• @clerk/nextjs weekly download count: https://api.npmjs.org/downloads/point/last-week/@clerk/nextjs (checked 2026-05-29)
• @stackframe/stack monthly download count: https://api.npmjs.org/downloads/point/last-month/@stackframe/stack (checked 2026-05-29)
• @clerk/nextjs monthly download count: https://api.npmjs.org/downloads/point/last-month/@clerk/nextjs (checked 2026-05-29)