Two tools for the same job — with different trade-offs
Machine-to-machine API authentication boils down to one question: how does service A prove to service B that it’s allowed to make this request? JWT and API keys both answer that question, but they do it differently, and the choice has downstream effects on complexity, performance, and operational overhead.
This isn’t a “JWTs are modern, API keys are legacy” comparison. Both are appropriate mechanisms in different contexts. The goal here is to be specific about when each is the right call.
API key authentication
An API key is an opaque shared secret. The caller presents it; the server looks it up and grants or denies access.
Strengths:
- Zero latency for validation — a simple hash or exact comparison, no cryptographic verification.
- Universally supported — any HTTP client can send a header.
- Immediately revocable — delete the key record and the caller is blocked on the next request.
- Simple to scope — the key’s permitted operations are defined server-side, not embedded in the token.
Weaknesses:
- No built-in identity claims — the key tells you which credential is calling, not who provisioned it or what roles they hold.
- Long-lived by default — keys don’t expire unless you build rotation into your process.
- Must be stored securely — leakage via environment variables, logs, or source code is a constant operational risk.
In RequestRocket, API keys are modelled as credentialAuthType: "key" for target credentials (upstream APIs that require a static key), and as the recommended type for proxy credentials (what your services use to authenticate to the gateway):
POST /clients/{clientId}/credentials
{
"credentialType": "target",
"credentialAuthType": "key",
"credentialName": "clearbit-enrichment",
"credentialRegion": "us-east-1",
"credentialSecret": {
"key": "sk_clearbit_xxxxxxxxxxxxxx"
}
}JWT authentication
A JWT (JSON Web Token) is a self-describing signed token that carries claims — identity, roles, expiry, audience — embedded in the payload. The receiver verifies the signature against a known public key (via JWKS) rather than looking the token up in a database.
Strengths:
- Claims-bearing —
sub,iss, and custom claims can be read by the service without an additional lookup. - Short-lived — a typical M2M JWT expires in 5–60 minutes, limiting the window for a leaked token.
- Stateless verification — no database lookup required; the signature is the proof.
Weaknesses:
- Revocation is hard — a valid, unexpired JWT cannot be invalidated without a blocklist, which reintroduces database state.
- Complexity — you need a token issuer (Auth0, Okta, a custom OAuth2 server), JWKS endpoint, token refresh logic, and clock-skew handling.
- Short expiry creates churn — automated renewal adds latency and failure modes to your integration.
RequestRocket supports credentialAuthType: "jwtVerify" for proxy credentials where RequestRocket validates an incoming JWT before forwarding:
POST /clients/{clientId}/credentials
{
"credentialType": "target",
"credentialAuthType": "jwt",
"credentialName": "internal-analytics-api",
"credentialRegion": "us-east-1",
"credentialSecret": {
"privateKey": "-----BEGIN RSA PRIVATE KEY-----\n...",
"algorithm": "RS256",
"claims": {
"iss": "my-service",
"aud": "analytics-api"
}
}
}Decision framework
| Scenario | Recommended |
|---|---|
| Calling a third-party API with a static vendor key | API key (key) |
| Upstream API issues short-lived JWTs | JWT (jwt) |
| Your callers already have Auth0 / Okta M2M tokens | JWT verify (jwtVerify) |
| You need claims (user ID, tenant, roles) at the gateway | JWT verify (jwtVerify) |
| Simple service-to-service with no claims needed | API key (key) |
| OAuth2 flow with dynamic token refresh | OAuth2 (oauth2) |
Combining both at the proxy layer
A common and practical configuration uses both: an incoming jwtVerify proxy credential authenticates the caller and validates their claims, while the upstream target uses a key or bearer credential. RequestRocket handles the translation transparently.
POST /clients/{clientId}/proxies
{
"proxyName": "stripe-payment-api",
"proxyRegion": "us-east-1",
"proxyProxyCredentialId": "<auth0-m2m-verify-id>",
"proxyTargetId": "<stripe-target-id>",
"proxyTargetCredentialId": "<stripe-api-key-id>",
"proxyDefaultRuleEffect": "deny"
}The caller authenticates with a JWT; the upstream receives a Bearer token injected by the gateway. No credential translation logic in your application code.
The operational reality
For most teams, the operational cost of a full OAuth2/JWT M2M setup isn’t justified unless you already have an identity provider in place and need the claims. If your M2M scenario is “service A calls service B with a static key managed by a central team”, API keys with good scoping and rotation discipline are the practical choice.
If you’re seeing pressure to adopt JWTs specifically because of concerns about key management (rotation, leakage, blast radius) — a gateway layer addresses those concerns without requiring you to rebuild your auth model.
Next steps
Both mechanisms are supported natively in RequestRocket, and you can mix them across proxies as your needs evolve. Explore the credential documentation or start for free.