We’re building a custom dashboard in Berlin and switched to the implicit grant flow for the React app. The token comes back fine, but when we try to validate it client-side using jose, it throws JWEInvalid: invalid algorithm. We’re passing RS256 but the header seems off. Here’s the validation code:
const { JWTPayload } = await jwtVerify(token, secret, {
algorithms: ['RS256'],
});
The token payload looks valid, but the verification step chokes. Is there a specific endpoint to fetch the public key for implicit grant tokens, or are we missing a step?
The docs say implicit grant tokens are opaque strings for the client, not signed JWTs you can verify locally with a public key. You’re trying to decode a blob that Genesys doesn’t expose the signing key for.
In .NET, I usually just send the token to a backend API to validate. Don’t try to parse it in React. It’s a security risk and technically unsupported for this flow.
Here’s how I handle it in an Azure Function:
var client = new PureCloudPlatformClientV2.ClientConfiguration
{
AccessToken = httpContext.Request.Headers["Authorization"].FirstOrDefault()?.Replace("Bearer ", "")
};
try
{
var usersClient = new PureCloudPlatformClientV2.UsersApi(client);
await usersClient.GetUsersMeAsync(); // Validates token implicitly
return Ok(new { valid = true });
}
catch (Exception ex)
{
return Unauthorized(new { valid = false, error = ex.Message });
}
The SDK handles the auth header and expiration checks. If GetUsersMe succeeds, the token is good. If it throws, it’s expired or invalid. Stop trying to use jose on the frontend. It won’t work.