Validating Genesys Cloud JWT in React without server-side verification

NICE CXone API & Integrations
1

Building a standalone React dashboard that pulls Genesys Cloud data directly from the client. Using the implicit grant flow to get the access token. The token comes back fine, but I need to validate the exp and iss claims locally before making API calls to avoid 401s.

Tried using jwt-decode to inspect the payload, but it doesn’t verify the signature. Just looking for a lightweight way to check if the token is still valid and issued by Genesys without hitting a backend service.

Current setup:

  • React 18
  • axios for API calls
  • Implicit grant via Genesys Cloud login page
  • Token stored in memory (not localStorage)

Snippet of what I’m checking:

import { jwtDecode } from 'jwt-decode';

const validateToken = (token) => {
 try {
 const decoded = jwtDecode(token);
 const now = Math.floor(Date.now() / 1000);
 if (decoded.exp < now) return false;
 if (decoded.iss !== 'https://api.mypurecloud.com') return false;
 return true;
 } catch (e) {
 return false;
 }
};

Is this enough, or do I need to fetch the public keys from the JWKS endpoint to verify the signature? The docs are vague on client-side validation requirements.