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JSON Repair & Schema Validation
x402
JSON Repair & Schema Validation is a paid API for AI agents from x402.fenixfoundry.com, paid per call via x402, $0.003/call, status unknown (last checked 2026-09-14).
Repairs malformed JSON (trailing commas, single quotes, unquoted keys, code fences, truncated output) and optionally validates the fixed result against a JSON Schema, returning the parsed value, canonical text, change log, and validation errors.
Price / call$0.003
Success—
StatusUnknown
How this service works
Repair malformed JSON (trailing commas, single quotes, unquoted keys, code fences, truncated output) and optionally validate the result against a supplied JSON Schema. Returns the parsed value, the canonical text, a change log and validation errors.
Output
Returns the repaired parsed JSON value, the canonical (prettified) JSON text, a structured change log describing every modification made during repair, and any validation errors if a JSON Schema was supplied.
Example use cases
Fixing LLM-generated JSON output
“The model returned JSON wrapped in a markdown code fence with trailing commas — can you strip the fences, fix the commas, and give me a clean parseable JSON object back?”
Validating pipeline data against a schema
“I have this JSON string with unquoted keys that I need cleaned up AND validated against my schema to make sure all required fields are present before I pass it downstream.”
Recovering truncated API response JSON
“My API response got cut off mid-JSON and now it won't parse — can you try to repair the truncated output and tell me what changes were made to fix it?”
Technical details
Endpoint
POSThttps://x402.fenixfoundry.com/repair-jsonWhen to prefer
Choose this endpoint when you need to both repair AND optionally validate JSON in a single call, especially for LLM-generated output that commonly has trailing commas, single quotes, unquoted keys, or markdown code fences. Ideal for agent pipelines where downstream steps require strict JSON compliance and you want a detailed change log of what was fixed.
Side effects
- Input is so severely malformed that repair is impossible — returns an error describing what could not be recovered
- Supplied JSON Schema is itself invalid — returns a schema validation error
- Truncation is too severe to infer the intended structure — partial repair with noted ambiguities
- Network or payment failure — HTTP 402 if payment not processed correctly
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| input | string | Malformed JSON text — trailing commas, single quotes, unquoted keys, markdown code fences, truncated output, etc. |
| schema | object | Optional JSON Schema (draft 2020-12) to validate the repaired value against. |
Tags
x402
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