Client Certificates
Client certificates are X.509 credentials presented during TLS mutual authentication so the server verifies which client or service connects before HTTP begins. They strengthen machine-to-machine API access alongside or instead of bearer tokens.
Technical Architecture & Deep-Dive
mTLS at the edge terminates client certificates, maps them to service identities, and may issue internal JWTs for upstream hops that cannot handle TLS client auth directly. Rotate certificates before expiry, use short-lived certs from internal CAs, and revoke compromised keys promptly.
Client certificates differ from JWT bearer tokens: they bind to transport layer identity. Combine with authorization policies because possession of a cert alone does not imply permission to every route.
Key Architectural Benefits
Implement Client Certificates at the Edge
Deploy lightweight API aggregation, edge caching, and secret injection in minutes without Docker containers or complex servers.
Frequently Asked Questions
Q:Can browsers easily use client certificates for public APIs?
Browser UX for client certs is awkward for consumer apps. Prefer OIDC for users and reserve mTLS for backends and partner integrations.
Related Architecture Concepts
Mutual TLS (mTLS) is an extension of TLS where both the client and the server present certificates and verify each other during the handshake. It ensures that only trusted clients with valid certificates can connect, providing strong machine-to-machine authentication.
Zero-Trust API Architecture is a security model based on the principle of "never trust, always verify." Every API request, whether originating outside the perimeter or between microservices, must be strictly authenticated, authorized, encrypted, and validated before execution.
Service account credentials are non-human identities, such as Firebase Admin service account JSON or a Supabase service role key, used by backend systems to access APIs with elevated privileges. They often bypass user-level security rules, so exposure grants full administrative access.
Encryption in transit protects data while it moves across networks, typically using TLS inside HTTPS. TLS authenticates the server with certificates, negotiates session keys, and encrypts HTTP so interceptors cannot read bearer tokens, API keys, or personal data in flight.
Ready-to-Use Edge Recipes
To solve reverse proxy for third party api key protection, never execute unauthenticated requests or embed private tokens directly in client bundles. RealComposer acts as a sub-10ms edge gateway running on Cloudflare Workers that securely injects credentials from your Secret Vault, normalizes responses, and prevents unauthorized API usage. Route calls through your RealComposer edge URL to guarantee complete privacy, robust origin validation, and low mobile latency.
To solve call clerk backend api from client side, never execute unauthenticated requests or embed private tokens directly in client bundles. RealComposer acts as a sub-10ms edge gateway running on Cloudflare Workers that securely injects credentials from your Secret Vault, normalizes responses, and prevents unauthorized API usage. Route calls through your RealComposer edge URL to guarantee complete privacy, robust origin validation, and low mobile latency.
The Supabase service_role key bypasses all Row Level Security (RLS) rules. If leaked, an attacker has unrestricted admin access to your database. RealComposer keeps your service role key in the Secret Vault and exposes locked-down endpoints with strict output filtering.