# Roman Numeral Converter and Validator

> Roman Numeral Converter and Validator is a paid API for AI agents from units-convert.x402tookit.com, paid per call via x402, $0.02/call, status unknown (last checked 2026-10-21).

Converts integers (1-3999) to Roman numerals, Roman numerals to integers, and validates whether a Roman numeral is in canonical form.

## Facts

- Endpoint: GET https://units-convert.x402tookit.com/roman-numerals?utm_source=zero.xyz
- Price: $0.02/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-21
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/roman-numeral-converter-and-validator-9a4450d2
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_Lm8yLHLRI40P55JsRMBQ5

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability roman-numeral-converter-and-validator-9a4450d2
```

Example prompt: Convert 1994 to a Roman numeral and also tell me if MCMXCIV is written in proper canonical form.

## When to prefer this

Choose this endpoint when you need to convert between Arabic integers and Roman numerals, or when you need to programmatically validate whether a Roman numeral string is written in correct canonical subtractive notation. It is the right choice for historical date display, Super Bowl numbering, clock face generation, or educational tools requiring Roman numeral correctness checks.

## Known failure modes

- Integer out of range (below 1 or above 3999) returns an error or null result
- Invalid non-numeric, non-Roman-numeral string input may produce null or error response
- Empty or missing 'value' query parameter returns a validation error
- Ambiguous input that is neither a valid integer nor a recognizable Roman numeral may yield a null verdict

## How this service works

Convert between integers (1-3999) and Roman numerals, and check whether a Roman numeral is written in canonical form.

## Output

Returns a JSON object containing the Roman numeral string, the integer equivalent, a verdict on whether the Roman numeral is in canonical form, a summary explanation, any reasons why it may not be canonical, and metadata such as source and timestamp.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [
      "value"
     ],
     "properties": {
      "value": {
       "type": "string",
       "description": "An integer 1-3999 or a Roman numeral such as MCMXCIV"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "properties": {
      "asOf": {
       "type": [
        "null",
        "string"
       ]
      },
      "roman": {
       "type": [
        "null",
        "string"
       ]
      },
      "source": {
       "type": [
        "null",
        "string"
       ]
      },
      "integer": {
       "type": [
        "null",
        "number"
       ]
      },
      "reasons": {
       "type": [
        "array",
        "null"
       ]
      },
      "summary": {
       "type": [
        "null",
        "string"
       ]
      },
      "verdict": {
       "type": [
        "null",
        "string"
       ]
      },
      "degraded": {
       "type": [
        "boolean",
        "null"
       ]
      },
      "disclaimer": {
       "type": [
        "null",
        "string"
       ]
      },
      "notChecked": {
       "type": [
        "array",
        "null"
       ],
       "items": {
        "type": "string"
       }
      }
     }
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/roman-numeral-converter-and-validator-9a4450d2/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from units-convert.x402tookit.com](https://www.zero.xyz/host/units-convert.x402tookit.com/llms.txt)