API Error Decoder Chrome Extension
Support
Find answers to common questions or reach out — we typically respond within 2 business days.
Quick Help
Capture not starting?
Click "Start Capture" in the panel, then refresh the page.
Request not showing a diagnosis?
Click the request row to expand the full diagnosis card.
JWT token inspection
Pro feature — click any request with an Authorization header to see decoded claims.
Replay a request
Pro feature — click "Replay" on any captured request to edit and resend it.
Export a request
Pro feature — click "Export" and choose cURL, Postman, or Debug JSON.
Unlock Pro
Sign in with your account and your Pro license will activate automatically.
Frequently Asked Questions
The extension is not capturing any failing requests. What should I do?
Make sure you clicked "Start Capture" in the extension panel before navigating to your page. The debugger only activates after you start capture. Try refreshing the page after starting capture.
Why are some failed requests missing from the list?
Requests that complete before capture is started will not appear. Also, requests made by service workers or browser extensions may not be captured depending on your Chrome version and configuration.
How do I open the API Error Decoder side panel?
Click the API Error Decoder icon in your Chrome toolbar. The panel opens in the DevTools side panel. You can also open it from the Extensions menu (puzzle icon) in Chrome.
What types of errors does API Error Decoder detect?
The extension captures and diagnoses 401 Unauthorized, 403 Forbidden, 404 Not Found, 422 Unprocessable Entity, 429 Too Many Requests, 5xx server errors, CORS errors, and network failures.
How do I use Request Replay?
This is a Pro feature. Click any captured request, then click "Replay". You can edit the request headers, body, and query params before resending. The response appears immediately in the panel.
How does JWT Inspection work?
This is a Pro feature. When a captured request includes a JWT token in the Authorization header, the extension automatically decodes it, shows the header and payload claims, and flags expired or soon-to-expire tokens.
How do I export a request?
This is a Pro feature. Click any captured request and select "Export". Choose from cURL command, Postman v2.1 collection, or Debug JSON report. The file is saved to your downloads folder.
I purchased Pro but my features are not unlocked. What should I do?
Make sure you are signed in with the same email address used during purchase. Try signing out and signing back in. If the issue persists, contact us with your purchase receipt and we will resolve it manually.
Does API Error Decoder work on all websites?
It works on most websites over http:// or https://. Chrome restricts extension access on chrome:// URLs, the Chrome Web Store, and some enterprise-managed pages.
Is my browsing data sent to your servers?
No. All API capture and diagnosis happens locally in your browser. The content of requests, responses, and JWT tokens never leaves your device. Only your account email (for Pro sign-in) is stored — see our Privacy Policy for details.
Can I get a refund?
The Pro license is non-refundable except where required by applicable consumer protection law. If you have a specific concern, please contact us and we will do our best to help.
Still need help?
Email us with a description of the issue, your Chrome version, and any steps to reproduce it. We aim to respond within 2 business days.
100plus.tools.support@gmail.com