Fix JSON punctuation API

Focused JSON syntax fixer for the most common LLM mistakes only — trailing commas, single quotes to double quotes, and unquoted object keys — without stripping prose or closing truncation; use when you trust the structure but not the punctuation. Answers 'how do I fix single quotes and trailing commas in this JSON?', 'why won't this nearly-valid JSON parse?'.

Price$0.02per request

MethodPOST

Route/v1/llm/fix-json-syntax

StatusLive

MIME typeapplication/json

Rate limit120/minute

Cache0s public

llmjsonfixtrailing-commasingle-quotessyntaxpunctuationagent

API URLhttps://x402.hexl.dev/v1/llm/fix-json-syntax

Integration docs

Example request

{
  "text": "{'a': 1, 'b': [2,3,],}"
}

Example response

{
  "fixed": "{\"a\": 1, \"b\": [2,3]}",
  "ok": true,
  "changes": [
    "single-to-double-quotes",
    "removed-trailing-commas"
  ]
}

Input schema

{
  "type": "object",
  "required": [
    "text"
  ],
  "properties": {
    "text": {
      "type": "string",
      "examples": [
        "{'a': 1, 'b': [2,3,],}"
      ]
    }
  }
}

Output schema

{
  "type": "object",
  "additionalProperties": true
}