Convert

Convert JSON values to match a schema

POST/v1/convert/json/types/to/schema

Fixes the type mismatches that make Parse JSON fail, such as Expected Integer but got Number or Expected String but got Integer. Numeric text becomes numbers, numbers and booleans become text, true and false text becomes booleans, and a missing nullable property becomes null. A value that cannot be converted safely (abc to integer, 42.5 to integer, null where null is not allowed) is left as it was and reported in failures. Every conversion is listed in changes.

Updated October 27, 2026

Request body

Name	Type	Required	Description
data	any	yes	The JSON document to fix, any JSON value
schema	object	yes	The schema, for example the one Parse JSON uses. Supported keywords: type (also a list), properties, required, items and nullable

Example request

A request body that works, as JSON.

{
  "data": [
    {
      "city": "Porto",
      "temp_c": "17.5",
      "rain": "false"
    },
    {
      "city": "Lisboa",
      "temp_c": "21",
      "rain": "false"
    }
  ],
  "schema": {
    "type": "array",
    "items": {
      "type": "object",
      "properties": {
        "temp_c": {
          "type": "number"
        },
        "rain": {
          "type": "boolean"
        }
      },
      "required": [
        "temp_c",
        "rain"
      ]
    }
  }
}

Code samples

Replace YOUR_TOKEN with your access token.

curl

curl -X POST 'https://api.skillfulsardine.com/v1/convert/json/types/to/schema' \
  -H 'Authorization: Bearer YOUR_TOKEN' \
  -H 'Content-Type: application/json' \
  --data-raw '{
  "data": [
    {
      "city": "Porto",
      "temp_c": "17.5",
      "rain": "false"
    },
    {
      "city": "Lisboa",
      "temp_c": "21",
      "rain": "false"
    }
  ],
  "schema": {
    "type": "array",
    "items": {
      "type": "object",
      "properties": {
        "temp_c": {
          "type": "number"
        },
        "rain": {
          "type": "boolean"
        }
      },
      "required": [
        "temp_c",
        "rain"
      ]
    }
  }
}'

PowerShell

$body = @'
{
  "data": [
    {
      "city": "Porto",
      "temp_c": "17.5",
      "rain": "false"
    },
    {
      "city": "Lisboa",
      "temp_c": "21",
      "rain": "false"
    }
  ],
  "schema": {
    "type": "array",
    "items": {
      "type": "object",
      "properties": {
        "temp_c": {
          "type": "number"
        },
        "rain": {
          "type": "boolean"
        }
      },
      "required": [
        "temp_c",
        "rain"
      ]
    }
  }
}
'@
$response = Invoke-RestMethod -Method Post -Uri 'https://api.skillfulsardine.com/v1/convert/json/types/to/schema' `
  -Headers @{ Authorization = 'Bearer YOUR_TOKEN' } `
  -ContentType 'application/json; charset=utf-8' `
  -Body ([System.Text.Encoding]::UTF8.GetBytes($body))
$response | ConvertTo-Json -Depth 10

Python

import requests

payload = {
    "data": [
        {
            "city": "Porto",
            "temp_c": "17.5",
            "rain": "false",
        },
        {
            "city": "Lisboa",
            "temp_c": "21",
            "rain": "false",
        },
    ],
    "schema": {
        "type": "array",
        "items": {
            "type": "object",
            "properties": {
                "temp_c": {
                    "type": "number",
                },
                "rain": {
                    "type": "boolean",
                },
            },
            "required": [
                "temp_c",
                "rain",
            ],
        },
    },
}

response = requests.post(
    "https://api.skillfulsardine.com/v1/convert/json/types/to/schema",
    headers={"Authorization": "Bearer YOUR_TOKEN"},
    json=payload,
    timeout=30,
)
print(response.json())

JavaScript

const response = await fetch("https://api.skillfulsardine.com/v1/convert/json/types/to/schema", {
  method: "POST",
  headers: {
    "Authorization": "Bearer YOUR_TOKEN",
    "Content-Type": "application/json",
  },
  body: JSON.stringify({
  "data": [
    {
      "city": "Porto",
      "temp_c": "17.5",
      "rain": "false"
    },
    {
      "city": "Lisboa",
      "temp_c": "21",
      "rain": "false"
    }
  ],
  "schema": {
    "type": "array",
    "items": {
      "type": "object",
      "properties": {
        "temp_c": {
          "type": "number"
        },
        "rain": {
          "type": "boolean"
        }
      },
      "required": [
        "temp_c",
        "rain"
      ]
    }
  }
}),
});
const result = await response.json();
console.log(result);

Node

// Node 18 or later. Save as call.mjs and run: API_TOKEN=... node call.mjs
const token = process.env.API_TOKEN;

const response = await fetch("https://api.skillfulsardine.com/v1/convert/json/types/to/schema", {
  method: "POST",
  headers: {
    "Authorization": `Bearer ${token}`,
    "Content-Type": "application/json",
  },
  body: JSON.stringify({
  "data": [
    {
      "city": "Porto",
      "temp_c": "17.5",
      "rain": "false"
    },
    {
      "city": "Lisboa",
      "temp_c": "21",
      "rain": "false"
    }
  ],
  "schema": {
    "type": "array",
    "items": {
      "type": "object",
      "properties": {
        "temp_c": {
          "type": "number"
        },
        "rain": {
          "type": "boolean"
        }
      },
      "required": [
        "temp_c",
        "rain"
      ]
    }
  }
}),
});
const result = await response.json();
console.log(result);

Rust

// Cargo.toml: reqwest = { version = "0.12", features = ["blocking", "json"] }, serde_json = "1"
fn main() -> Result<(), Box<dyn std::error::Error>> {
    let body: serde_json::Value = serde_json::from_str(r#"{
  "data": [
    {
      "city": "Porto",
      "temp_c": "17.5",
      "rain": "false"
    },
    {
      "city": "Lisboa",
      "temp_c": "21",
      "rain": "false"
    }
  ],
  "schema": {
    "type": "array",
    "items": {
      "type": "object",
      "properties": {
        "temp_c": {
          "type": "number"
        },
        "rain": {
          "type": "boolean"
        }
      },
      "required": [
        "temp_c",
        "rain"
      ]
    }
  }
}"#)?;
    let response = reqwest::blocking::Client::new()
        .post("https://api.skillfulsardine.com/v1/convert/json/types/to/schema")
        .bearer_auth("YOUR_TOKEN")
        .json(&body)
        .send()?;
    println!("{}", response.text()?);
    Ok(())
}

Swift

import Foundation

var request = URLRequest(url: URL(string: "https://api.skillfulsardine.com/v1/convert/json/types/to/schema")!)
request.httpMethod = "POST"
request.setValue("Bearer YOUR_TOKEN", forHTTPHeaderField: "Authorization")
request.setValue("application/json", forHTTPHeaderField: "Content-Type")
request.httpBody = Data(#"""
{
  "data": [
    {
      "city": "Porto",
      "temp_c": "17.5",
      "rain": "false"
    },
    {
      "city": "Lisboa",
      "temp_c": "21",
      "rain": "false"
    }
  ],
  "schema": {
    "type": "array",
    "items": {
      "type": "object",
      "properties": {
        "temp_c": {
          "type": "number"
        },
        "rain": {
          "type": "boolean"
        }
      },
      "required": [
        "temp_c",
        "rain"
      ]
    }
  }
}
"""#.utf8)

let (data, _) = try await URLSession.shared.data(for: request)
print(String(decoding: data, as: UTF8.self))

Response

The fields inside data of a successful response.

Name	Type	Required	Description
data	any	yes	The document after conversion. Failed values are unchanged
changes	array of CoerceChange	yes	Every conversion that was made
failures	array of CoerceFailure	yes	Every value that could not be converted
changed_count	integer	yes	Number of conversions
failed_count	integer	yes	Number of failures

Example response

A real answer from the operation, as JSON. The fields in the table above are inside data.

{
  "data": {
    "data": [
      {
        "city": "Porto",
        "temp_c": 17.5,
        "rain": false
      },
      {
        "city": "Lisboa",
        "temp_c": 21,
        "rain": false
      }
    ],
    "changes": [
      {
        "path": "$[0].temp_c",
        "from_value": "17.5",
        "to_value": 17.5,
        "message": "Converted str to number"
      },
      {
        "path": "$[0].rain",
        "from_value": "false",
        "to_value": false,
        "message": "Converted str to boolean"
      },
      {
        "path": "$[1].temp_c",
        "from_value": "21",
        "to_value": 21,
        "message": "Converted str to number"
      },
      {
        "path": "$[1].rain",
        "from_value": "false",
        "to_value": false,
        "message": "Converted str to boolean"
      }
    ],
    "failures": [],
    "changed_count": 4,
    "failed_count": 0
  },
  "errors": null,
  "meta": {
    "request_id": "1db1ecde-643f-41a8-8910-3ebd9a59c123",
    "timestamp": "2026-10-27T07:19:42.041167Z",
    "version": "2026-03-26"
  },
  "pagination": null
}

Responses

Status	When it happens
200	Successful Response
400	The body respects the operation schema, but the use case rejected it. Each problem is one ApiError entry
413	The request is larger than the request size limit of the API allows
422	The body does not respect the operation schema. Each problem is one ApiError entry with the code validation_error
500	Something failed inside the server and was not an input problem. The same envelope, errors may be empty