# Numeral Systems – Roman Numeral Converter

> Numeral Systems – Roman Numeral Converter is a paid API for AI agents from numeral.openverbs.com, paid per call via x402, $0.002/call, status unknown (last checked 2026-09-14).

Converts between Arabic integers (1–3999) and Roman numerals bidirectionally via a single POST call

## Facts

- Endpoint: POST https://numeral.openverbs.com/v1/roman
- Price: $0.002/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/numeral-systems-roman-numeral-converter-f48b9e7d
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_SM0qKo9mVsAzieRcaP3o4

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 numeral-systems-roman-numeral-converter-f48b9e7d -d '<json body>'
```

Example prompt: Convert 1994 to its Roman numeral equivalent — the value is 1994.

## When to prefer this

Use this endpoint when you need a quick, reliable bidirectional conversion between standard Arabic integers and classical Roman numerals (range 1–3999). Ideal for formatting chapter numbers, years, engraving text, clock faces, or decoding historical inscriptions. Prefer this over a general math API when the specific Roman numeral representation is the desired output.

## Known failure modes

- Input integer out of range (must be 1–3999): returns validation error
- Invalid Roman numeral string (malformed sequence): returns parsing error
- Empty or missing value field: returns required field error
- Value exceeds 32 character maxLength: returns validation error
- Non-integer string submitted as numeric input: returns type error

## How this service works

Convert between integers (1–3999) and Roman numerals in either direction — a digit string is encoded to Roman, a Roman numeral is decoded to an integer. Non-canonical numerals (IIII, IC) are rejected.

## Output

Returns the converted value: if an Arabic integer was submitted, the response contains the corresponding Roman numeral string; if a Roman numeral was submitted, the response contains the corresponding integer — along with any relevant metadata about the conversion.

## 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",
    "bodyType",
    "body"
   ],
   "properties": {
    "body": {
     "type": "object",
     "required": [
      "value"
     ],
     "properties": {
      "value": {
       "type": "string",
       "maxLength": 32,
       "minLength": 1,
       "description": "An integer 1–3999, or a Roman numeral like \"MCMXCIV\"."
      }
     },
     "additionalProperties": false
    },
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "POST"
     ],
     "type": "string"
    },
    "bodyType": {
     "enum": [
      "json",
      "form-data",
      "text"
     ],
     "type": "string"
    }
   },
   "additionalProperties": false
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/numeral-systems-roman-numeral-converter-f48b9e7d/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from numeral.openverbs.com](https://www.zero.xyz/host/numeral.openverbs.com/llms.txt)