Mint a session JWT
Exchanges the opaque uk_ct_… session for a short-lived, signed JWT that your backend can verify offline against the environment’s JWKS document (GET /v1/jwks/{publishableKey}) — no call back to this API on every request.
This is the refresh flow, and there is no second credential to manage: the opaque session is the refresh token. Call again whenever the last JWT is near expiry, for as long as the session lives.
The token lasts 5 minutes, and that is the whole revocation story: a JWT is verified offline, so nothing can recall one. Deleting the session stops the next refresh, which makes five minutes the longest a revoked session keeps working — and the reason the long-lived credential is the opaque, revocable one.
Each mint records the contact against the month’s active-contact meter, idempotently. See GET /v1/organization/usage/active-contacts.