How to Intercept and Refresh Expired JWT Tokens

Create a custom Axios network client export using 'axios.create()' with base configurations to avoid polluting the global Axios configuration object.

Attach a request interceptor via 'instance.interceptors.request.use()' to automatically inject active access tokens into outgoing HTTP requests.

Attach a response interceptor via 'instance.interceptors.response.use()' to catch incoming API error blocks before they reach user-facing catch blocks.

Inside the error handler, inspect 'error.response.status'. Look for specific status codes (like '401 Unauthorized') that signal an expired session token.

Inspect the custom request configuration property (e.g., 'error.config._retry'). If it is true, reject the promise immediately to prevent endless request loop conditions.

Flip the structural retry tracking parameter flag 'originalRequest._retry = true' to lock down this specific execution configuration context.

Dispatch a separate async network call directly to your auth server refresh endpoint, sending secure refresh tokens stored inside HttpOnly cookies.

Save the newly returned access token into your application runtime state memory or client storage blocks.

Update the authorization headers of the original request with the fresh token, and pass it back to the instance client: 'return axiosInstance(originalRequest)'.

If the refresh token attempt fails or returns an error, catch the exception, clear local application data caches, and redirect the user back to the login page.