# paidfor.dev

> An index of x402 sellers on Base mainnet, built by paying them. 12992 paid API calls; 859 failed the buyer (failure_rate 0.06611761083743842). Per-seller failure rates with 95% Wilson intervals, evidence with on-chain transaction hashes, and a verdict (avoid, caution, ok) for every seller with at least 30 paid calls.

Every page has a Markdown twin: append .md to the path, or send Accept: text/markdown.

## Pages

- [Leaderboard](https://paidfor.dev/index.md): every seller, sorted by failure rate, plus the reliable list
- [Seller page](https://paidfor.dev/seller/api-xpay.com.md): one per seller at /seller/<domain>.md
- [Methodology](https://paidfor.dev/methodology.md): taxonomy, sampling, settlement matching, caps, limitations
- [Stress tests](https://paidfor.dev/stress.md): duplicate and timeout settlement findings
- [API and MCP](https://paidfor.dev/api.md): routes, the /v1/check contract, webhooks
- [Changes](https://paidfor.dev/changes.md): what changed in the index, newest first (RSS: https://paidfor.dev/changes.xml)
- [Install the MCP server](https://paidfor.dev/install.md): per-client setup an agent can follow, ending in a verification call
- [Full report](https://paidfor.dev/report.md): the frozen 2026-10-24 to 2026-10-26 study
- [All sellers, one line each](https://paidfor.dev/llms-full.txt)

## API (JSON, CORS open, no keys, no rate limit)

- GET https://paidfor.dev/v1/summary
- GET https://paidfor.dev/v1/sellers?min_calls=30&sort=rate
- GET https://paidfor.dev/v1/seller/{domain}
- GET https://paidfor.dev/v1/check?url={resource url or domain}  (verdict + one sentence; contract on /api)
- GET https://paidfor.dev/v1/demand?days=7  (hosts ranked by lookups)
- GET https://paidfor.dev/v1/reported  (operator-reported series, payments proven on Base, next to the measured numbers)
- GET https://paidfor.dev/v1/changes?since=<ISO>&host=<host>  (what changed, newest first; RSS at https://paidfor.dev/changes.xml)
- POST https://paidfor.dev/v1/subscriptions  (webhook alerts, no account: { webhook_url, hosts } returns id, manage_token and secret once)

## MCP

- Streamable HTTP: https://mcp.paidfor.dev/mcp
- stdio: npx @paidfor/mcp
- Install instructions for agents: https://paidfor.dev/install.md (also https://paidfor.dev/llms-install.md)
- Tools: check_x402_seller({ url }), list_reliable_sellers({ category?, limit? }), recent_changes({ host?, since? })

## Source data

- https://raw.githubusercontent.com/sarmadahsan/paidfor-data/main/summary.json (generated_at 2026-10-29T05:21:51.991Z)
- https://raw.githubusercontent.com/sarmadahsan/paidfor-data/main/sellers.json, resources.json, stress.json, probe.json, evidence/<domain>.json
- Repo: https://github.com/sarmadahsan/paidfor-data