Public API Finder

Find free/public APIs for agents, prototypes, demos, and integrations.

Powered by multiple sources plus a curated best-known API layer:

• public-api-lists/public-api-lists for fast curated JSON discovery
• public-apis/public-apis for the larger canonical README list
• APIs-guru/openapi-directory for OpenAPI-backed APIs

Quick start

npx --yes --package=@builtbyecho/public-api-finder -- public-api-finder "weather forecast" --no-auth --https
npx --yes --package=@builtbyecho/public-api-finder -- public-api-finder "crypto prices" --category Cryptocurrency --limit 5
npx --yes --package=@builtbyecho/public-api-finder -- public-api-finder "jobs" --json
npx --yes --package=@builtbyecho/public-api-finder -- public-api-finder "payments" --openapi
npx --yes --package=@builtbyecho/public-api-finder -- public-api-finder "weather forecast" --no-auth --https --check

Why

Agents often waste time wandering the web for APIs. This gives them a small, predictable first stop: search a curated list, filter by auth/HTTPS/CORS, then verify the chosen API docs before coding.

Skill

The package includes an agent skill at:

skills/public-api-finder/SKILL.md

The skill tells agents to prefer the CLI first, then live-check docs/endpoints before building. Use --check when you want the CLI to annotate whether each result URL is reachable right now.

CLI options

--category <name>  Filter by category substring
--source <name>    Filter by source: public-api-lists, public-apis, apis-guru, curated
--no-auth          Only APIs with Auth = No
--https            Only HTTPS APIs
--cors <value>     Filter by CORS: Yes, No, Unknown
--openapi          Only APIs with OpenAPI specs
--limit <n>        Max results
--check            Live-check result URLs and annotate reachability
--json             Emit JSON
--refresh          Refresh cache

Bankr x402 endpoint

This repo includes a Bankr x402 Cloud endpoint scaffold at:

x402/public-api-finder/index.ts
bankr.x402.json

It is configured as a paid POST endpoint at $0.01 USDC per successful request on Base. Deploy it with Bankr when ready:

bankr x402 deploy public-api-finder

Current BuiltByEcho production endpoint:

https://x402.bankr.bot/0x2a16625fad3b0d840ac02c7c59edea3781e340ae/public-api-finder

The endpoint accepts:

{
  "query": "weather forecast no auth cors",
  "limit": 5,
  "noAuth": true,
  "https": true,
  "cors": "Yes"
}

Suggested Bankr App prompt after deployment:

Build me a public app called Public API Finder. It should have a search box,
filters for no-auth, HTTPS, CORS, category, and result limit, and a green
button labeled “Pay $0.01 & Pull”. When clicked, call my x402 endpoint
https://x402.bankr.bot/0x2a16625fad3b0d840ac02c7c59edea3781e340ae/public-api-finder with bankr.x402.fetch,
show the Bankr payment confirmation, then render ranked API cards with name,
category, auth, CORS, URL, score, and description. Make it public/unlisted so
I can share it with the Bankr team.

Hosted app / Bankr-ready credits

The package also includes a tiny zero-dependency hosted API and landing page:

npm start
# http://localhost:8787

Pricing model: 1 credit = 1 successful enriched pull. The default public price is $0.01 per pull, so a 100-credit top-up is $1.00.

API

# Create a Bankr-ready top-up order
curl -X POST http://localhost:8787/api/credits/topup \
  -H 'content-type: application/json' \
  -H 'x-api-key: acct_demo' \
  -d '{"credits":100}'

# Search, spending 1 credit only when results are returned
curl -X POST http://localhost:8787/api/search \
  -H 'content-type: application/json' \
  -H 'x-api-key: acct_demo' \
  -d '{"query":"weather forecast no auth cors","noAuth":true,"https":true,"cors":"Yes"}'

Top-ups currently return Bankr payment instructions and create a pending order. After confirming payment, grant credits with an admin token:

PUBLIC_API_FINDER_ADMIN_TOKEN=secret npm start

curl -X POST http://localhost:8787/api/admin/credits \
  -H 'content-type: application/json' \
  -H 'x-admin-token: secret' \
  -d '{"account":"acct_demo","credits":100,"paymentRef":"bankr-tx-or-job-id"}'

Environment knobs:

PORT                              Server port, default 8787
PUBLIC_API_FINDER_STATE           Ledger JSON path, default ./state/public-api-finder-ledger.json
PUBLIC_API_FINDER_PULL_PRICE_CENTS Price per pull, default 1
PUBLIC_API_FINDER_CREDITS_PER_PULL Credits charged per successful search, default 1
PUBLIC_API_FINDER_ADMIN_TOKEN      Required for manual credit grants
BANKR_RECEIVE_ADDRESS              Address shown in Bankr payment instructions
BANKR_NETWORK                      Default Base
BANKR_ASSET                        Default USDC