Developer surface

Conversion API and embeds

Use Convematik's no-auth JSON endpoints for single conversions, batch conversions, catalog discovery, unit metadata and lightweight widgets. Error responses use HTTP 400 with JSON shaped as {"error":"..."}.

Run a request

Single conversions use query parameters and return JSON.

GET https://api.convematik.com/convert?value=1&from=kg&to=lb

{
  "value": 1.0,
  "from": "kg",
  "to": "lb",
  "result": 2.20462262185
}
OpenAPI JSON Batch converter

Batch demo

Batch output appears here after the API responds.

Widget embed generator

<iframe
  title="Convematik converter"
  src="https://convematik.com/widget/?value=78&from=kg&to=lb"
  width="360"
  height="420"
  loading="lazy"></iframe>

Open the widget gallery for preset embeds and attribution snippets.

Endpoint reference

All endpoints return JSON. Use https://api.convematik.com in production or http://localhost:8000 for local API development.

GET /health

Example: /health

Success: API status such as {"status":"ok"}.

GET /capabilities

Example: /capabilities

Success: version, tool count, endpoint list and feature states.

GET /tools

Example: /tools

Success: generated tool catalog grouped by category.

GET /search

Example: /search?q=kg

Success: up to 20 matching tool records.

GET /convert

Example: /convert?value=78&from=kg&to=lb

Success: numeric result with original value and unit aliases.

POST /batch

Example: JSON body with conversions array.

Success: ordered result list for up to 100 conversions.

GET /roman

Example: /roman?roman=XIV or /roman?integer=2026

Success: Roman numeral and integer pair.

GET /fraction

Example: /fraction?numerator=42&denominator=56&op=simplify

Success: simplified fraction, decimal or percent result.

GET /table

Example: /table?from=kg&to=lb&start=1&end=10&step=1

Success: conversion table rows.

GET /bmi

Example: /bmi?weight=70&height=1.75&unit=metric

Success: BMI value and category.

GET /electrical

Example: /electrical?watts=1200&volts=120&target=amps

Success: calculated watts, amps or volts.

GET /percentage

Example: /percentage?mode=percent-of&x=20&y=150

Success: percentage result and formula.

GET /age

Example: /age?birth_date=1990-01-15&as_of=2026-06-12

Success: years, months, days and total days.

GET /date-difference

Example: /date-difference?start=2026-06-01&end=2026-06-12

Success: day difference with inclusive flag.

GET /tip

Example: /tip?subtotal=80&tip_percent=20&people=2

Success: tip, total and per-person split.

GET /discount

Example: /discount?price=120&discount_percent=25&tax_percent=8

Success: discount, discounted price, tax and total.

GET /fuel-cost

Example: /fuel-cost?distance=240&efficiency=30&fuel_price=3.75

Success: fuel used and trip fuel cost.

GET /unit-price

Example: /unit-price?price=12.99&quantity=3&unit=lb

Success: price per unit.

GET /units

Example: /units

Success: unit aliases grouped by category for selectors and widgets.

GET /openapi.json

Example: /openapi.json

Success: OpenAPI 3.0 contract for client generation and docs.