Best Verification APIs 2026
Six verification APIs compared on features, pricing, reliability, security, and AI agent integration. Real data from official documentation — not marketing claims.
Feature Matrix
| Feature | Proof | Twilio | Auth0 | Vonage | Sinch | Telesign |
|---|---|---|---|---|---|---|
| Phone verification | ||||||
| Email verification | ||||||
| Domain verification | ||||||
| Wallet verification | ||||||
| Social verification | ||||||
| Reverse OTP | ||||||
| Proof tokens (offline) | OIDC only | |||||
| HITL approvals | Push only | CIBA (preview) | Push (MFA) | |||
| MCP server | 131 tools | Alpha | ||||
| Free tier | 300/mo | 25K MAU |
Pricing Comparison
| Provider | Model | Price | Free Tier | Notes |
|---|---|---|---|---|
| Proof of Holdings | Per-proof (any type) | From €0.0079 | 300/mo | Same price for phone, email, domain, wallet, social |
| Telesign | Per-verification | From $0.0072 | None | Phone SMS only. Cheapest per-SMS at scale |
| Twilio Verify | Per-verification + fees | From $0.05 | None | Base fee + channel fees (SMS, voice). Phone + email only |
| Vonage Verify | Per-verification + fees | From €0.052 | None | Platform fee + channel fees. Phone + email |
| Sinch | Per-request | $0.01-0.06 | None | Phone only. Country-variable pricing |
| Auth0 | Per-MAU | From $35/mo | 25K MAU | Identity platform, not per-verification. Phone needs Twilio backend |
Category Winners
Best value multi-asset
Only platform where one price covers phone, email, domain, wallet, and social. €0.0079/proof on Business plan.
Most verification channels
30+ channels across 5 asset types: Telegram, WhatsApp, SMS, Magic Link, DNS, HTTP, OAuth, wallet signing.
Best for AI agents
131 MCP tools + HITL with cryptographic proof tokens. Twilio and Sinch have MCP servers but limited scope.
Only Reverse OTP
User sends code to service. 0% delivery failure, SIM-swap immune. No other platform offers this.
Only portable proof tokens
RS256 JWT verifiable offline. Share with third parties. Auth0 has OIDC tokens but they're session-bound.
Cheapest phone-only SMS
$0.0072/verification. Phone SMS only, no other asset types. Best for high-volume phone-only use cases.
Strongest social login
30+ social providers, enterprise SSO, SAML, LDAP. Full identity platform, not just verification.
Best flash call
Missed-call OTP with caller ID. 70% faster, 25% lower cost than SMS. Android auto-intercept.
Security Comparison
All providers use HTTPS and encrypt data in transit. The key security differences are in the verification method and what happens after verification:
| Security Feature | Proof | Others |
|---|---|---|
| SIM-swap resistant | Yes (Reverse OTP) | No (SMS is vulnerable) |
| Cryptographic proof of verification | RS256 JWT | Status flag only (except Auth0 OIDC) |
| Offline verification | Yes (public key) | No |
| No PII stored | Hashed identifiers only | Varies (Auth0 stores profiles) |
Detailed Comparisons
Frequently Asked Questions
Try Proof of Holdings
300 free proofs per month. All 5 asset types. No credit card required.