Broken JSON repair API
Fix JSON as LLMs often write it: removes ```json fences and surrounding prose, comments and trailing commas, converts single quotes, quotes bare keys, maps True/False/None, and closes unclosed brackets. Returns the repaired JSON and whether it now parses. Use when an LLM's JSON output fails to parse.
When to use it
- Fix JSON with trailing commas, single quotes or missing brackets
- Repair LLM output that is almost JSON
- Clean data before parsing
Inputs
| Name | Type | Description |
|---|---|---|
text (required) | string | The broken JSON text |
Request
Over HTTP, with a card key from /credits:
curl -H "Authorization: Bearer adt_…" "https://tools.funwords.eu/json/repair?text=%60%60%60json%0A%7Bname%3A%20'Ada'%2C%20tags%3A%20%5B'x'%2C%5D%2C%7D%0A%60%60%60"Or one of your 25 free calls, no key:
curl "https://tools.funwords.eu/json/repair?text=%60%60%60json%0A%7Bname%3A%20'Ada'%2C%20tags%3A%20%5B'x'%2C%5D%2C%7D%0A%60%60%60&trial=1"Without a key, the same URL answers 402 Payment Required with x402 and MPP terms, so an agent with a wallet pays per call in USDC (Base, Polygon, Arbitrum or Solana over x402; Base or Tempo over MPP) and retries.
Example result
{
"repaired": "{\"name\":\"Ada\",\"tags\":[\"x\"]}",
"valid": true
}From an AI agent (MCP)
Add the MCP server to Claude, Cursor or any MCP client. This tool is json_repair, and the first 25 successful calls are free:
https://tools.funwords.eu/mcpQuestions
What if it cannot be repaired?
The call fails and is not charged.
How do I pay?
Each successful call costs $0.01; failed calls are not charged. The first 25 calls are free. Then pay with card credits (from $1; the key goes in an Authorization header or, for clients that can only fetch a URL, as api_key= in the URL) or per call in USDC over x402 or MPP. No account is needed.