Validate a JSON value against a JSON Schema and coerce common LLM-output mistake
Validate a JSON value against a JSON Schema and coerce common LLM-output mistakes (numbers as strings, stringified booleans, scalars where arrays are expected, missing defaults, extra properties). Returns the coerced value plus a structured error report. Built for cleaning up LLM tool-call arguments and structured outputs. POST a JSON body like: {"schema":{"type":"object","required":["name","age"],"properties":{"name":{"type":"string"},"age":{"type":"integer"}}},"data":{"name":"Ada","age":"36"}}
Paid test badge: not yet. The checks above are free: we call the tool without paying and read the payment request it sends back. The Verified badge needs paid calls whose answers match the promised output, and nobody can buy a badge.
Endpoint
POST https://keyronne.com/api/validate-json
| Category | Code and developer |
|---|---|
| Provider host | keyronne.com |
| Networks | eip155:8453 |
| Payment schemes | exact |
| Self-reported calls, 30 days | 2 from 2 payers (the provider's figure, not ours) |
Our checks, last 30 days
| Day | Result | HTTP | Asked | Time |
|---|---|---|---|---|
| 2026-09-24 | valid payment request | 402 | $0.001 | 59 ms |
Example input (from the provider)
{
"body": {
"data": {
"age": "36",
"name": "Ada"
},
"schema": {
"properties": {
"age": {
"type": "integer"
},
"name": {
"type": "string"
}
},
"required": [
"name",
"age"
],
"type": "object"
}
},
"bodyType": "json",
"method": "POST",
"type": "http"
}
Promised output schema (from the provider)
{
"$schema": "https://json-schema.org/draft/2020-12/schema",
"properties": {
"input": {
"properties": {
"body": {
"properties": {
"coerce": {
"default": true,
"description": "Attempt type coercion and default-filling before validating.",
"type": "boolean"
},
"data": {
"description": "The candidate JSON value to validate and coerce."
},
"schema": {
"description": "JSON Schema (draft-07 style subset: type, properties, required, items, enum, const, additionalProperties, min/max constraints, pattern, default).",
"type": "object"
}
},
"required": [
"schema",
"data"
],
"type": "object"
},
"bodyType": {
"enum": [
"json"
],
"type": "string"
},
"method": {
"enum": [
"POST"
],
"type": "string"
},
"type": {
"const": "http",
"type": "string"
}
},
"type": "object"
},
"output": {
"properties": {
"errors": {
"items": {
"properties": {
"message": {
"type": "string"
},
"path": {
"type": "string"
}
},
"type": "object"
},
"type": "array"
},
"valid": {
"type": "boolean"
},
"value": {
"description": "The (possibly coerced) value."
},
"warnings": {
"items": {
"properties": {
"message": {
"type": "string"
},
"path": {
"type": "string"
}
},
"type": "object"
},
"type": "array"
}
},
"type": "object"
}
},
"required": [
"input"
],
"type": "object"
}