​

invalid_json

​

Example response

{
  "error": {
    "code": "invalid_json",
    "message": "Request body contains invalid JSON",
    "docs_url": "https://docs.avatcado.com/errors/invalid_json"
  },
  "meta": {
    "request_id": "550e8400-e29b-41d4-a716-446655440000"
  }
}

​

What happened?

• The JSON syntax is malformed (missing quotes, trailing commas, unescaped characters)
• The request body is empty when JSON was expected
• The body contains non-JSON content (e.g. form-encoded data)

​

How to fix

1. Validate your JSON: Use a JSON linter or JSON.parse() locally before sending
2. Set the Content-Type header: Include Content-Type: application/json
3. Check for trailing commas: JSON does not allow trailing commas after the last element

# Correct
curl -X POST https://api.avatcado.com/v1/validate/batch \
  -H "Authorization: Bearer avat_live_your_api_key" \
  -H "Content-Type: application/json" \
  -d '{"vat_numbers": ["NL123456789B01"]}'

# Wrong - trailing comma
curl -X POST https://api.avatcado.com/v1/validate/batch \
  -H "Authorization: Bearer avat_live_your_api_key" \
  -H "Content-Type: application/json" \
  -d '{"vat_numbers": ["NL123456789B01",]}'

​

Common mistakes

• Trailing commas: ["a", "b",] is invalid JSON
• Single quotes: JSON requires double quotes. {'key': 'value'} is invalid
• Unescaped characters: Special characters in strings must be escaped
• Empty body: Sending a POST with no body when JSON is expected

​

Catching this error with the SDKs

import Avatcado, { ValidationError } from '@avatcado/node';

const avatcado = new Avatcado('avat_live_your_api_key');
const { data, error } = await avatcado.vat.validate({ vatNumber: '...' });

if (error instanceof ValidationError) {
  console.log(error.message);
  console.log(error.details); // Array<{ field, message }> | null
}

from avatcado import Avatcado, ValidationError

avatcado = Avatcado("avat_live_your_api_key")

try:
    result = avatcado.vat.validate("...")
except ValidationError as e:
    print(e.message)
    print(e.details)  # list of dicts or None

​

Related errors

• validation_error - JSON is valid but fails schema validation