Roman Numeral Converter API

GET

Switch between standard numbers and Roman numerals in either direction.

Roman Numeral Converter is a bidirectional tool for converting between Arabic numbers (1-3999) and Roman numerals. It provides detailed breakdowns of the conversion process.

Try it — live request, no key required

Request

GETapi.apiverve.com/v1/romanconverter?number=2024

Query parameters

numberinteger

Verification

Format

No key required to try it. Get a key to use it in your app.

Example

{
  "status": "ok",
  "error": null,
  "data": {
    "number": 2024,
    "roman": "MMXXIV",
    "breakdown": {
      "M": 2,
      "X": 2,
      "IV": 1
    }
  }
}

About the Roman Numeral Converter API

Roman Numeral Converter works by converting numbers to Roman numerals using standard notation (I, V, X, L, C, D, M) or converting Roman numerals back to numbers. Supports numbers 1-3999 and validates Roman numeral syntax.

What people use it for

Document Formatting: Convert numbers to Roman numerals for page numbering, chapter headings, or formal document sections
Historical Data: Convert Roman numeral dates and numbers from historical documents into modern numeric format
Educational Tools: Teach Roman numeral systems by providing conversions and detailed breakdowns of numeral components
Content Generation: Generate Roman numerals for lists, outlines, or hierarchical structures in generated content

Ways to call it

One endpoint, many ways in — REST with JSON, XML, YAML and CSV, plus GraphQL and an MCP interface for AI agents.

JSON: Default REST response
XML: Markup format
YAML: Human-readable
CSV: Tabular export
GraphQL: Query language
MCP: For AI agents

View all integrations →

Other ways to use Roman Numeral Converter

Same data, same APIVerve account, same credit balance — one key works on all of them.

Give it to an AI agentConnect over MCP and your agent calls it as a native tool — Claude, Cursor, ChatGPT.on VerveKit Google Sheets or ExcelA =VERVE() formula fills a column — no script, no export, recalculates in place.on VerveSheets Ground an agent on itA cited, machine-checkable fact your model can't produce on its own.on VerveContext

Questions.

Common questions about the Roman Numeral Converter API.

Read the docs →

What range of numbers does the converter support?

The API handles whole numbers from 1 through 3,999. It operates on standard Roman numeral notation using standard symbols I, V, X, L, C, D, and M alongside standard subtractive pairings.

Can I convert Roman numerals back into standard integers?

Yes, conversions work bidirectionally. You can send an integer to receive the Roman numeral equivalent, or pass a Roman numeral string to parse it into an Arabic number.

Which plan fits 20,000 conversions a month?

The Starter plan easily covers 20,000 conversions a month. At 2 credits per conversion, Starter provides up to 100,000 calls each month, which works out to about $0.30 per 1,000 conversions. The Free plan includes 100 conversions per month for testing.

Do I get the symbol breakdown on the Free plan?

The Free plan provides the primary conversion results, but detailed symbol breakdowns require a paid plan. Paid plans unlock counts for base symbols like M, C, and X, as well as subtractive pairs like IV, XL, and CM.

Can the converter process numbers outside the 1 to 3,999 range?

No, the converter is strictly bounded between 1 and 3,999. Standard Roman numeral notation cannot represent zero, negative numbers, or numbers 4,000 and higher without non-standard vinculum bars, so inputs outside this range are not supported.

Request parameters — GET /v1/romanconverter

Sent in the query string. Premium parameters are accepted on every plan but only take effect on plans that include them. Anything not listed here is dropped rather than passed through.

Required

Parameter	Type	Example	Description
`number`Required	integer	`2024`	The number to convert to Roman numerals range 1-3999

Example request

1
2

curl "https://api.apiverve.com/v1/romanconverter?number=2024" \
  -H "x-api-key: YOUR_API_KEY"

Authentication

Send your key in the x-api-key header. That is the only auth step — no token exchange, and no per-endpoint scope to configure.

Header	When	Value
`x-api-key`Required	Every request	Your API key. Header names are case-insensitive, so `X-API-Key` is the same header.
`Authorization`Alternate	Instead of the above	`Bearer <key>` — for clients that only expose bearer auth. Resolves to the same account and the same billing.

401 is the only auth verdict

A 401 means the key is missing, invalid or expired. A 403 means the key is valid but not permitted here — blocked by a key restriction or an IP allow-list. Running out of credits is a 429.

Response — GET /v1/romanconverter

Every APIVerve endpoint returns the same three top-level keys, so one response handler covers your whole integration: status, error and data. Only data changes shape.

Sample response

{
  "status": "ok",
  "error": null,
  "data": {
    "number": 2024,
    "roman": "MMXXIV",
    "breakdown": {
      "M": 2,
      "X": 2,
      "IV": 1
    }
  }
}

Response fields

Paths are relative to data. Premium fields are absent rather than zeroed on plans that do not include them, so check for presence instead of comparing to 0.

Field	Type	Example	Description
`number`	number	`2024`	The original number provided for conversion
`roman`	string	`"MMXXIV"`	The Roman numeral representation of the number
`breakdown`	object	`{...}`	Object containing Roman numeral components and their counts
`M`Premium	number	`2`	Count of M (1000) symbols in breakdown
`X`Premium	number	`2`	Count of X (10) symbols in breakdown
`IV`Premium	number	`1`	Count of IV (4) subtractive pairs in breakdown

Response headers

Every response carries your balance, so your own code always knows where it stands without polling anything. All four are exposed to browsers through CORS.

Header	What it carries
`x-api-remaining-credits`	Credits left in the current cycle
`x-api-credits-used`	Credits spent in the current cycle
`x-api-max-credits`	The allowance for the cycle
`x-api-version`	Version of the endpoint that answered

Errors

Read the HTTP status first, then error for the specific reason. The body names the parameter that has to change.

Status	Meaning	What to do
`400`	Input was rejected	Read `error`; it names the parameter that has to change.
`401`	Key missing or invalid	Check the header name and the key value.
`403`	Key valid, but not permitted here	A key restriction or an IP allow-list — never a bad key.
`429`	Rate limited, or out of credits	Read `error` to tell them apart, then back off or top up.

What a call costs — 2 credits per call

Credits are shared across every APIVerve API — one balance, one key, one bill. Failed requests never count against it, so a rejected input costs nothing.

Plan	Per month	Credits	Roman Numeral Converter calls	Per 1,000 calls
Free	Free	200	100	Free
Starter	$29.99	200,000	100,000	$0.30
Pro	$99.99	1,000,000	500,000	$0.20
Mega	$299.99	4,000,000	2,000,000	$0.15

Calls are what the credits buy at this API's rate — spend them here, on any of the other APIs, or across both. Nothing is reserved per endpoint.

Compare all pricing tiers →

Call it from cURL — GET /v1/romanconverter

No SDK to install — this is a plain HTTPS call to /v1/romanconverter with your key in the x-api-key header. Swap in a real key and it runs as-is.

cURL

1
2

curl "https://api.apiverve.com/v1/romanconverter" \
  -H "x-api-key: YOUR_API_KEY"

Resources

GitHubapiverve/romanconverter-apiSource, issues and the examples this page is built from.ReferenceRoman Numeral Converter API docsEvery parameter, every response field, and the errors.ParametersWhat this call acceptsRequired and optional inputs, with example values.

Also published for

@apiverve/romanconverternpm APIVerve.API.RomanNumeralConverterNuGet

Only the languages APIVerve ships a client for are listed — the rest call the endpoint directly over HTTPS.

Call it from Node.js — GET /v1/romanconverter

Install the Node.js SDK, then call the Roman Numeral Converter API with your key. The client wraps the same HTTPS request, so anything it returns is what the endpoint returns.

Install — npm

npm install @apiverve/romanconverter

Node.js

const res = await fetch("https://api.apiverve.com/v1/romanconverter", {
  headers: { "x-api-key": "YOUR_API_KEY" },
});
const { data } = await res.json();
console.log(data);

Resources

npm@apiverve/romanconverterThe published Node.js client, versioned and signed.GitHubapiverve/romanconverter-apiSource, issues and the examples this page is built from.ReferenceRoman Numeral Converter API docsEvery parameter, every response field, and the errors.ParametersWhat this call acceptsRequired and optional inputs, with example values.

Also published for

APIVerve.API.RomanNumeralConverterNuGet

Only the languages APIVerve ships a client for are listed — the rest call the endpoint directly over HTTPS.

Call it from Python — GET /v1/romanconverter

No SDK to install — this is a plain HTTPS call to /v1/romanconverter with your key in the x-api-key header. Swap in a real key and it runs as-is.

Python

import requests

res = requests.get(
    "https://api.apiverve.com/v1/romanconverter",
    headers={"x-api-key": "YOUR_API_KEY"},
)
print(res.json()["data"])

Resources

Also published for

@apiverve/romanconverternpm APIVerve.API.RomanNumeralConverterNuGet

Only the languages APIVerve ships a client for are listed — the rest call the endpoint directly over HTTPS.

Call it from C# / .NET — GET /v1/romanconverter

Install the C# / .NET SDK, then call the Roman Numeral Converter API with your key. The client wraps the same HTTPS request, so anything it returns is what the endpoint returns.

Install — NuGet

dotnet add package APIVerve.API.RomanNumeralConverter

C# / .NET

using var client = new HttpClient();
client.DefaultRequestHeaders.Add("x-api-key", "YOUR_API_KEY");

var json = await client.GetStringAsync("https://api.apiverve.com/v1/romanconverter");
Console.WriteLine(json);

Resources

NuGetAPIVerve.API.RomanNumeralConverterThe published C# / .NET client, versioned and signed.GitHubapiverve/romanconverter-apiSource, issues and the examples this page is built from.ReferenceRoman Numeral Converter API docsEvery parameter, every response field, and the errors.ParametersWhat this call acceptsRequired and optional inputs, with example values.

Also published for

@apiverve/romanconverternpm

Only the languages APIVerve ships a client for are listed — the rest call the endpoint directly over HTTPS.

Call it from Go — GET /v1/romanconverter

No SDK to install — this is a plain HTTPS call to /v1/romanconverter with your key in the x-api-key header. Swap in a real key and it runs as-is.

req, _ := http.NewRequest("GET", "https://api.apiverve.com/v1/romanconverter", nil)
req.Header.Set("x-api-key", "YOUR_API_KEY")

res, _ := http.DefaultClient.Do(req)
defer res.Body.Close()
body, _ := io.ReadAll(res.Body)
fmt.Println(string(body))

Resources

Also published for

@apiverve/romanconverternpm APIVerve.API.RomanNumeralConverterNuGet

Only the languages APIVerve ships a client for are listed — the rest call the endpoint directly over HTTPS.

Call it from PHP — GET /v1/romanconverter

No SDK to install — this is a plain HTTPS call to /v1/romanconverter with your key in the x-api-key header. Swap in a real key and it runs as-is.

PHP

$ch = curl_init("https://api.apiverve.com/v1/romanconverter");
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_HTTPHEADER, ["x-api-key: YOUR_API_KEY"]);

$response = curl_exec($ch);
echo $response;

Resources

Also published for

@apiverve/romanconverternpm APIVerve.API.RomanNumeralConverterNuGet

Only the languages APIVerve ships a client for are listed — the rest call the endpoint directly over HTTPS.

Call it from Ruby — GET /v1/romanconverter

No SDK to install — this is a plain HTTPS call to /v1/romanconverter with your key in the x-api-key header. Swap in a real key and it runs as-is.

Ruby

require "net/http"

uri = URI("https://api.apiverve.com/v1/romanconverter")
req = Net::HTTP::Get.new(uri)
req["x-api-key"] = "YOUR_API_KEY"

res = Net::HTTP.start(uri.hostname, uri.port, use_ssl: true) { |h| h.request(req) }
puts res.body

Resources

Also published for

@apiverve/romanconverternpm APIVerve.API.RomanNumeralConverterNuGet

Only the languages APIVerve ships a client for are listed — the rest call the endpoint directly over HTTPS.

Data Conversion

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Roman Numeral Converter API

Try it — live request, no key required

About the Roman Numeral Converter API

What people use it for

Ways to call it

Other ways to use Roman Numeral Converter

Questions.

Request parameters — GET /v1/romanconverter

Required

Authentication

Response — GET /v1/romanconverter

Response fields

Response headers

Errors

What a call costs — 2 credits per call

Call it from cURL — GET /v1/romanconverter

Resources

Also published for

Call it from Node.js — GET /v1/romanconverter

Resources

Also published for

Call it from Python — GET /v1/romanconverter

Resources

Also published for

Call it from C# / .NET — GET /v1/romanconverter

Resources

Also published for

Call it from Go — GET /v1/romanconverter

Resources

Also published for

Call it from PHP — GET /v1/romanconverter

Resources

Also published for

Call it from Ruby — GET /v1/romanconverter

Resources

Also published for

Zero-code embed — one snippet, no backend

Changelog — Roman Numeral Converter API

Data Conversion

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