Debug API JSON
Paste any API response and find the problem: wrong types, missing fields, or structure that does not match the docs.
1,000 free AI credits on signup · Core tools run locally
How to debug an API response
- 1
Paste the response into the editor
Copy the raw body from your client, curl, or logs and paste it into the editor. No sample handy? Open /editor?sample=stripe-webhook to try the workflow on a real-shaped payload.
- 2
Format and validate
Formatting reflows the JSON, and validation flags syntax errors with the exact line and column. A trailing comma or unquoted key shows up right where it broke.
- 3
Explore the shape as a tree or mind map
Switch to the tree or mind map to see nesting and types at a glance. A value that should be an array but came back as an object, or a number wrapped in quotes, stands out in this view.
- 4
Run AI Explain on confusing fields
For a field you do not recognize, run AI Explain in the Copilot. It returns what the field represents and its type, and clicking a field jumps to it in the editor.
What helps you debug
Line-level validation
Syntax errors report the line and column, so you fix the exact character that broke the parse instead of eyeballing the whole body.
Type-coloured tree view
Strings, numbers, booleans, and null each render in their own colour, so a value of the wrong type shows up without scanning the whole body.
Mind map of the whole shape
See the whole structure as a graph. Nested or repeated objects stand out, ready to compare against what the API docs promised.
Two-way highlighting
Click a node in the mind map or a field in an AI result and the editor scrolls to it. Click in the editor and the map follows.
Local by default
Format, validate, tree, and mind map all run in the browser. Your API response is sent to our servers only when you choose to run an AI action.
Frequently asked questions
Does my API data get uploaded?
Not for the core tools. Formatting, validation, the tree view, and the mind map run entirely in your browser, so the response stays on your machine. Data is sent to our servers only when you explicitly run an AI Copilot action like Explain.
Can it handle big responses?
Yes. The core tools parse and render large payloads in the browser. The mind map and tree let you collapse branches so a few thousand fields stay navigable.
What if the JSON is broken?
Validation points at the first syntax error with its line and column, which is usually a stray comma, an unquoted key, or a truncated body. To see how a malformed example reads, open /editor?sample=broken-json.
Why is my API returning HTML instead of JSON?
The server sent an error page, an auth redirect landed you on a login screen, or the URL is wrong and you got a 404 page. Log response.text() before parsing to see what actually came back — an HTML body starts with < and explains itself. For the parse error this triggers, see the Unexpected token in JSON guide at /unexpected-token-in-json.
Is it free?
The core debugging tools are free and need no account. AI Copilot actions use credits, and new accounts start with 1,000 free credits.