paidfor is an index of x402 sellers built by paying them. It buys their endpoints with USDC on Base, checks what was delivered, and records every failure: no delivery after payment, a quote above the listed price, a changed pay-to address, or a malformed response. The connector reads that public index. It has three read-only tools: check_x402_seller: pass an x402 resource URL or a seller domain and get a verdict (avoid, caution, ok or unknown), one sentence explaining it, the seller's paid-call count and failure rate with a 95% interval, the listed price, typical quote and largest overcharge when known, and links to the seller page and raw evidence. list_reliable_sellers: sellers with zero failures across at least 30 paid calls, optionally by category (inference, data, scraping, compute, other). recent_changes: what changed in the index, newest first: verdict changes, new failures, moved quotes, changed pay-to addresses and seller replies, for one seller or all. The connector never pays, holds no wallet, and needs no account or key. It sends only the URL or domain being checked. Methodology and raw data are public at paidfor.dev.
