Feature Comparison
What each provider actually ships as of March 2026. Not "coming soon" — what you can use today.
| Feature | Auth1 | Auth0 | Clerk | SuperTokens | Firebase Auth |
|---|---|---|---|---|---|
| SMS OTP | Yes | Yes (paid) | Yes | Yes (BYO Twilio) | Yes |
| Multi-Tenancy | Native (per-tenant isolation) | Organizations add-on | Organizations (paid) | App-level only | No |
| PII Encryption at Rest | AES-256-GCM per field | Enterprise only | No | No | No |
| Post-Quantum Readiness | Dilithium + Kyber | No | No | No | No |
| Self-Hosted Option | Yes (open-source auth-shield) | No | No | Yes | No |
| Rust Performance Layer | Native napi-rs middleware | No | No | No | No |
| Rate Limiting | Rust token bucket (in-process) | WAF-based | Basic | Redis-based | Firebase-level |
| Token Confusion Protection | Separate access/refresh secrets | Shared signing key | Opaque tokens | Configurable | N/A |
Pricing at Scale
This is where the differences become material. Authentication pricing models vary wildly, and the costs diverge fast as you scale past 10,000 monthly active users.
| Provider | Free Tier | 10,000 MAU | 100,000 MAU | 1M MAU |
|---|---|---|---|---|
| Auth1 | 1,000 MAU | $49/mo | $199/mo | Custom |
| Auth0 | 7,500 MAU | $228/mo | $1,140+/mo | Enterprise |
| Clerk | 10,000 MAU | Free | $1,800/mo | $19,800/mo |
| SuperTokens | Unlimited (self-host) | $50/mo | $500+/mo | Custom |
| Firebase Auth | 50K MAU | Free | Free | ~$30/mo |
Clerk's $0.02 per MAU after the free tier means at 100K users you pay $1,800/month for authentication alone. At 1M users, that is $19,800/month. For authentication. A solved problem.
Performance
Rust fused middleware (auth-shield): JWT verify + tenant resolve + rate limit + UUID: 4.36us/request Throughput: 229,574 ops/sec Standard JS middleware chain (jsonwebtoken + express-rate-limit): JWT verify + UUID generation only: 184.19us/request Throughput: 5,429 ops/sec Speedup: 42.28x faster
At 50,000 requests per second, the JS middleware chain consumes 9.2 seconds of CPU time per second on auth overhead alone. The Rust middleware consumes 0.22 seconds. That is the difference between needing 10 API servers and needing 1.
When to Choose Each
Choose Auth0 if: you are an enterprise with a procurement process that favors established vendors, you need 65+ social OAuth providers, and you have budget for Professional or Enterprise tier.
Choose Clerk if: you are building a React or Next.js application and developer experience is your top priority. Your user count should stay under 100K MAU where pricing is manageable.
Choose SuperTokens if: you want full control and plan to self-host with a permissive open-source license.
Choose Firebase Auth if: you are building a prototype or small project and multi-tenancy is not a requirement.
Choose Auth1 if: you are building a multi-tenant SaaS platform, performance matters (sub-10-microsecond auth middleware), you want PII encryption at rest without an enterprise contract, and predictable pricing matters more than the cheapest possible option.
The auth-shield Library
Regardless of which managed platform you choose, auth-shield is open source and works with any Node.js application. It provides fused JWT middleware, Argon2id password hashing, timing-safe comparison, OTP generation, PII field encryption, API key generation, rate limiting, and input sanitization.
npm install auth-shield
Final Thoughts
There is no universally best auth provider. There is only the best one for your specific constraints — budget, stack, scale, and security requirements.
What we would push back on is accepting the premise that authentication should cost $0.02 per user per month in perpetuity. JWT verification is a solved cryptographic primitive. Password hashing is a solved cryptographic primitive. These are not unsolved problems that justify rent-seeking pricing models.