JSON Validate, Repair, Convert, Query & Diff API

Validate, repair, format, query, diff, convert, and canonicalize JSON in one call.

Every AI agent and developer runs into broken or confusing JSON constantly. This tool handles all the most common JSON headaches in one place: check if JSON is valid (with exact error location), fix near-JSON that has typos or formatting mistakes, pretty-print or minify, pull out specific values using a path expression, compare two JSON documents and see exactly what changed, convert to and from YAML or CSV, produce a byte-stable canonical form for hashing or signing, validate against a schema, and get size and structure statistics. Same input always gives the same output — fully predictable, no side effects.

$0.01 per request — pay via x402/USDC. No account needed.

Send the 'op' field to choose what to do. Use 'data_raw' (a plain string) only for 'validate' and 'repair' — these two need the original broken text. Use 'data' (actual parsed JSON) for all other operations: format, canonicalize, convert, query, diff, patch, schema, stats. For 'diff' and 'patch', put the first document in 'data' and the second in 'options.data_b'. For 'query', put your JSONPath expression (e.g. '$.items[*].id') in 'options.jsonpath' or a JSON Pointer (e.g. '/items/0/id') in 'options.pointer'. For 'convert', set 'options.to' to 'yaml', 'csv', 'ndjson', or 'json'. For 'schema', put the JSON Schema object in 'options.schema'. For 'format', set 'options.indent' (number, default 2) and 'options.sort_keys' (true/false). For 'canonicalize', no extra options needed — output is RFC 8785 JCS bytes as a string. The 'repair' operation is heuristic: it always returns 'fixes_applied' so you can audit what changed. Check the 'valid' field first in every response. On a 400 error, read 'detail' for a plain-English explanation of what went wrong.

{
  "op": "query",
  "data": {
    "order": {
      "id": "A-1029",
      "items": [
        {
          "sku": "BIL-CUE-07",
          "qty": 2
        },
        {
          "sku": "BIL-CHALK-01",
          "qty": 5
        }
      ]
    }
  },
  "options": {
    "jsonpath": "$.order.items[*].sku"
  }
}

{
  "op": "validate",
  "data_raw": "{}"
}

{
  "op": "repair",
  "data_raw": "{name:'Ada', role:'Engineer', active:true,}",
  "options": {
    "pretty": true
  }
}

{
  "op": "diff",
  "data": {
    "config": {
      "version": 3,
      "retries": 5,
      "timeout": 30,
      "features": [
        "auth",
        "logging",
        "metrics"
      ]
    },
    "users": [
      {
        "id": 1,
        "role": "admin"
      },
      {
        "id": 2,
        "role": "viewer"
      }
    ]
  },
  "options": {
    "data_b": {
      "config": {
        "version": 4,
        "retries": 5,
        "timeout": 60,
        "features": [
          "auth",
          "logging"
        ]
      },
      "users": [
        {
          "id": 1,
          "role": "admin"
        },
        {
          "id": 2,
          "role": "editor"
        }
      ]
    }
  }
}

{
  "api_version": "1.0.0",
  "op": "query",
  "valid": true,
  "matches": [
    {
      "path": "$.order.items[0].sku",
      "value": "BIL-CUE-07"
    },
    {
      "path": "$.order.items[1].sku",
      "value": "BIL-CHALK-01"
    }
  ],
  "match_count": 2
}