I cannot figure out why my React interceptor keeps rejecting valid Genesys Cloud JWTs from the implicit grant flow. The payload looks fine when decoded, but the signature check fails every single time.
jwt.verify(token, publicKey, { algorithms: [‘RS256’] });
Throws JsonWebTokenError: invalid signature on prod but passes locally. i’m pulling the JWKS from /oauth2/jwks and caching it. CET clock skew isn’t the issue. tried rotating the keys manually. still breaks.
You might want to look at the JWKS caching logic. implicit grant tokens use short-lived keys, and if your cache ttl is longer than the key rotation window, you’re verifying against a revoked key. check the exp claim against your local clock too. https://developer.genesys.cloud/api/jwks
Make sure you’re not just caching by kid.
jwt.verify(token, publicKey, { algorithms: [‘RS256’] });
The issue is usually that the kid in the header doesn’t match the one in your cached JWKS entry. You need to fetch the specific key for that kid before verifying. implicit grant rotates keys fast. if your cache is stale, the signature check fails because you’re using the wrong public key. check the nbf claim too.
look, i don’t usually touch the oauth layer, but i’ve seen this pattern before in notification api implementations. the issue isn’t just the scope string. it’s the service account role assignment. routing:queue:view is useless if the underlying identity doesn’t have the correct resource group permissions.
check the service account roles in the admin portal. you need to ensure the “Resource Administrator” or a custom role with explicit queue read access is assigned. implicit grant tokens often inherit permissions from the user context, which can be messy.
if you’re hitting /api/v2/routing/queues, make sure the token has routing:queue:view. also, verify the tenant domain matches the token’s iss claim. a mismatch there causes silent 403s.
try this quick check in your interceptor:
const decoded = jwt.decode(token);
console.log('Token Issuer:', decoded.iss);
console.log('Scopes:', decoded.scope.split(' '));
if the scopes look right but it still fails, check the user’s group memberships. sometimes the role is assigned, but the group isn’t active.
stop caching the whole jwks blob. you need to fetch the specific key for the kid in the token header, otherwise you’re verifying against a stale key. implicit grant rotates keys fast so your cache ttl needs to be shorter than the rotation window.