Paste your broken JSON here and click "Fix JSON!!" to repair itEnter Invalid JSON

What is JSON Fixer?

Got broken JSON? We've all been there: a missing quote, a trailing comma, single quotes copied out of a Python dict, or a key someone forgot to quote. Paste your broken JSON (JavaScript Object Notation) on the left, hit Fix, and you get valid JSON back on the right.

JSON's syntax is strict. Keys need double quotes, there are no trailing commas and no comments, and every bracket has to close. The full grammar is in the RFC 8259 JSON specification, and MDN's JSON reference covers how JavaScript reads it. This tool earns its keep on API responses that came back mangled, database exports, and config files you edited by hand at 6pm.

How it works: when you click Fix JSON!!, your input is sent to our server and repaired by an AI model. We don't store it, and each request is capped at 64 KB. Because the fix comes from an AI model, give the result a quick look before you use it, especially long arrays and numbers.

How to Use the JSON Fixer

Follow these steps to repair broken JSON. Each step uses the actual buttons and panels on this page.

Paste Broken JSON or Load Sample

Paste your invalid JSON into the left editor, or click Sample JSON to load a broken example (an unquoted key, single quotes, a trailing comma and a missing comma). Here's the kind of input the fixer handles:

{subscriberId: "SUB-1001", plan: "5G", dataUsage: [45, 60, ]}

Typical repairs: quoting bare keys, swapping single quotes for double quotes, dropping trailing commas, adding missing commas and closing brackets, so the result parses under RFC 8259.

Click Fix JSON!!

Click the green Fix JSON!! button. Your JSON is sent to our server, an AI model repairs the syntax, and the result comes back into the right panel. A loading overlay shows while it works, usually a few seconds. Both panels highlight JSON syntax so you can compare before and after.

Review Fixed Output

The right panel shows the repaired JSON. The model is told to fix syntax only and leave keys and values alone, but it's still an AI model, so compare the output with your input before you use it. Then copy it or download it as fixed.json.

When You'd Actually Use This

API Debugging

A service returned a body with a trailing comma, or a log line chopped off the closing brace. Paste the response, fix it, and you have a document you can actually inspect.

Manual Edits

You edited a JSON file by hand and now it won't load. Missing commas, single quotes and unquoted keys are the usual suspects, and they're exactly what this fixes.

Data Migration

Data dumped from an older system often comes out as "almost JSON": Python-style quotes, True/None, stray commas. Fix a sample record here before you write the real migration script.

Development

Test fixtures and config files pick up typos fast. Fix them here and paste them back. If your team keeps hand-editing config, JSON5 is worth a look, since it allows comments and trailing commas by design.

Common Questions

Is my JSON sent anywhere?

Yes. When you click Fix JSON!!, the text in the left editor is sent to our server, which passes it to an AI model and returns the repaired version. We don't store it. If the JSON holds secrets or personal data, strip those out first, or find the errors yourself with the JSON Validator.

What types of errors can it fix?

Missing or mismatched quotes, single quotes, unquoted keys, trailing or missing commas, unclosed brackets and braces, and stray characters. If JSON.parse throws a SyntaxError at you, this is usually the kind of problem behind it. A badly truncated document may only be partly recoverable.

Will it change my data?

It shouldn't. The model is told to fix syntax only and never add, remove or rename keys or values. But it's an AI model, not a parser, so mistakes can happen. Compare the output with your input, especially long arrays, very large numbers and strings with escape sequences.

What if the JSON can't be fixed?

If the structure is too broken, you'll get an error message instead of output. Fix the worst part by hand first (usually a missing closing bracket or a chopped-off end), then run it again.

Can I use it for large JSON files?

Up to 64 KB per request. Anything bigger is stopped before it's sent, with a message saying so. For a big file, find the broken section with the validator and fix just that chunk here.

Is the fixed JSON always valid?

Usually, but not always. Paste the result into the JSON Validator to confirm it parses before you rely on it.

Other JSON Tools You Might Need

Fixing JSON is just one thing you might need. Here are some other tools that work great together: