JSON API

Every tool on this site is also an API: append &format=json to any tool URL and the result comes back as JSON. Same parameters as the web form (they're in the URL when you use the form, so you can build a request by copying your browser's address bar). Free, no key required — please be gentle (requests are rate-limited).

Example: generate a CRC module in CI

curl -s 'https://libfpga.com/tools/crc-generator?preset=crc32&dwidth=8&format=json' \
  | python3 -c 'import json,sys; print(json.load(sys.stdin)["code"][0]["text"])' \
  > crc32_d8.v

Response shape

{
  "tool":   "crc-generator",
  "params": { ... the validated inputs that were used ... },
  "values": [ ["Polynomial", "0x04C11DB7 (top bit implicit)"], ... ],
  "notes":  [ "..." ],
  "code":   [ { "title": "Verilog", "lang": "verilog", "text": "module ..." } ],
  "table":  { "title": "...", "headers": [...], "rows": [[...]] }   // some tools
}

Invalid input returns HTTP 400 with {"error": "..."}. Out-of-range values are clamped and reported in "warnings".

Endpoints

Parameter names and defaults for each endpoint: open the tool page, set the form, press Calculate, and read the query string — or call the endpoint with no parameters to see the defaults echoed in params.