HLPlanet Keyboard API

Free JSON API for keyboard size data: the standard layouts from full-size to 60%, the measured case size of 30 keyboards reviewed on HLPlanet, side-by-side comparisons, desk and mousepad fit, and which sizes have a given key. It returns the same numbers as the HLPlanet keyboard size comparison, which draws every layout to scale.

Base URL

https://api.hlplanet.com/v1

No API key or sign-up. Responses are JSON, served with Access-Control-Allow-Origin: * so you can call the API from a browser.

Quick start

curl "https://api.hlplanet.com/v1/compare?items=tkl,75"

const res = await fetch("https://api.hlplanet.com/v1/desk-fit?keyboard=tkl&desk_width_cm=120&mousepad=large");
const fit = await res.json();
console.log(fit.mouse_room_cm, fit.pad_fits);

Endpoints

Method and path	What it returns
`GET /v1/sizes`	Every standard size with key count, typical dimensions and missing keys. Docs
`GET /v1/sizes/{id}`	One size: `full`, `1800`, `tkl`, `75`, `65` or `60`. Docs
`GET /v1/keyboards`	The 30 measured keyboards, filterable by `size` and `q`. Docs
`GET /v1/keyboards/{id}`	One measured keyboard with its review link. Docs
`GET /v1/compare`	Two to six sizes or keyboards side by side. Docs
`GET /v1/desk-fit`	Whether a keyboard and mousepad fit on a desk. Docs
`GET /v1/keys/{key}`	Which sizes have a key or key group. Docs
`GET /v1/tools`	Free HLPlanet keyboard and controller testers. Docs

Errors use one JSON shape for every endpoint: see Errors.

MCP server for AI assistants

The same data is available as MCP tools at https://api.hlplanet.com/mcp (Streamable HTTP, no sign-in). Claude, Cursor, VS Code and Hermes Agent can connect to it directly: see MCP server.

Machine-readable docs

OpenAPI 3.0 specification for Postman, RapidAPI and code generators.
llms.txt indexes these docs for AI agents. Every page is also available as Markdown: add .md to its URL, or send Accept: text/markdown.

Attribution

The API is free to use. When you publish its numbers, please credit HLPlanet with a link to https://www.hlplanet.com/keyboard-layout/. Every response that comes from the size comparison includes a compare_url or source you can link to.

Where the numbers come from

Standard sizes are built from their key layouts with 19.05 mm per key plus an estimated 10 mm case border. Measured keyboards use the case width and depth from each HLPlanet review. Once you have a keyboard, check every key, rollover and chatter with the free HLPlanet keyboard tester.