API & MCP

Everything a person can do on Sizewise Scale Comparison, a program or AI agent can do with the same inputs and get the identical result.

HTTP API

POST https://sizewisescalecompare.usefulweb.app/api/v1/calculate – run Sizewise Scale Comparison
GET https://sizewisescalecompare.usefulweb.app/api/v1/tool – inputs, output schema, examples
OpenAPI 3.1: /openapi.json · /openapi.yaml
Errors: application/problem+json; 422 includes per-field errors.

Sizewise Scale Comparison

Compares the sizes of up to 24 things — from atoms and viruses to skyscrapers, stars and galaxies — and draws them to the same scale or as pairs with the ratio between neighbours. 337 objects come from Wikidata with their sources; add your own as “Name = 1.8 m”.

Inputs of Sizewise Scale Comparison
Field	Type	Default	Description
`objects`	textarea	"Statue of Liberty, Eiffel Tower, Burj Khalifa, Me = 1.8 m"	Objects (comma or new line between them). Names from the Sizewise list (for example Blue whale, Earth, Burj Khalifa), Wikidata IDs such as Q243, or your own object as “Name = 9 m”.
`sort`	select (size, input)	"size"	Order
`layout`	select (true-scale, pairs)	"true-scale"	Drawing
`title`	text	—	Title on the drawing

Example request

Landmarks and you

curl -X POST https://sizewisescalecompare.usefulweb.app/api/v1/calculate -H 'content-type: application/json' -d '{"objects":"Statue of Liberty, Eiffel Tower, Burj Khalifa, Me = 1.8 m","sort":"size","layout":"true-scale"}'

Every result contains

inputs (normalised, defaults applied), summary, result (validated against the published schema), units, assumptions, sources, warnings, computedAt and links.

MCP (Model Context Protocol)

Streamable HTTP endpoint: https://sizewisescalecompare.usefulweb.app/mcp – protocol revisions 2026-07-28 (stateless) and 2025-11-25 / 2025-06-18 / 2025-03-26 (initialize handshake).
Tools: sizewise_scale_compare
Local stdio connector: node src/mcp-stdio.ts --tool=sizewise-scale-compare

{
  "mcpServers": {
    "sizewise-scale-compare": { "type": "http", "url": "https://sizewisescalecompare.usefulweb.app/mcp" }
  }
}