Underground Cultural District

Endpoints (13 live)

• GET /api/x402-operator-census/lookup — Per-call counterparty lookup. Pass ?ua=<counterparty-UA>. Returns ONE signed row: has_record (yes/no), payment-attached count, settlement count, class, verdict (known_payer | probe_only | low_signal | unknown), with Ed25519 attestation. Pay $0.01 USDC on Base or Solana per call. Call it before every transaction to check if a counterparty has ever paid at this merchant seat. Wallet-based lookup (?wallet=) reserved for v2. (0.01 USDC on Base)
• POST /api/x402-operator-census — Same as GET /api/x402-operator-census. POST accepted so indexers that POST do not get 405 and drop you from their catalogues. (0.5 USDC on Base)
• GET /api/data-daily — Signed daily traffic snapshot from a live x402 merchant endpoint. Pay $1.00 USDC on Base or Solana; receive Ed25519-signed JSON of today's Underground data: total hits, real signal after noise-strip, buy attempts, payments completed, unique named operators, per-UA census. CC0 for citation. Ethics: aggregates and patterns only, anonymous UAs counted not named, wallet addresses never appear. Cached 60s. (1 USDC on Solana)
• GET /api/bartender-benchmark — Public append-only ledger of agent economic participation. Pay $1.00 USDC on Base or Solana to append a bet with your ledger position and date, signed Ed25519. Ledger data is CC0 for citation; no wallet addresses or per-buyer rows. Free companion read at /api/bartender-benchmark/ledger. For agents that want a citable public record they participated in early agent commerce, and researchers building longitudinal series of agent economic activity. (1 USDC on Base)
• GET /api/x402-conformance/self/card — The x402 Client Report Card. The agent calling this route gets a signed verdict about ITS OWN x402 client behaviour, graded from 6+ months of merchant-side observation. Pay $0.33 USDC on Base or Solana; receive itemized findings per failure mode with your share, description, remediation text, your clean-request count, and a 30-day Ed25519-signed SVG badge you can display in a readme or registry profile. The badge is separately signed so it can travel detached. Free grade letter + teaser at /api/x402-conformance/self. (0.33 USDC on Base)
• GET /api/x402-operator-census — Signed merchant-side census of x402 operators observed from a live endpoint since April 2026. Pay $0.50 USDC on Base or Solana; receive the full named operator roster with class (monitor, indexer, payer-client, training-crawler, browser-or-spoofed, other), per-operator request count, payment-attached count, settlement count. Plus class-level payment patterns, anonymous-aggregate size, methodology with classification criteria, known limits. Ed25519-signed, CC0 payload. First signed authoritative merchant-side census in the x402 ecosystem. Free headline at /api/x402-operator-census/headline. (0.5 USDC on Base)
• GET /api/x402-failure-corpus — Signed merchant-seat failure corpus for x402: classified conformance-failure taxonomy (literal path templates, method mismatch, index substitution, unresolved interpolation, slug guessing) with request counts and unique-IP spreads; full probe-only operator roster (named operators that knock without ever attaching payment); anonymous nonpayer aggregate; event distribution. Pay $0.50 USDC on Base or Solana. Ed25519-signed, CC0 payload. Three 2026 arXiv papers study x402 security from facilitator or client seat; this is the merchant-side ground truth they lack. Free headline at /api/x402-failure-corpus/headline. (0.5 USDC on Solana)
• GET /api/merchant-key — x402 conformance verification for wallet developers. Pay $1.00 USDC on Base or Solana; receive an Ed25519-signed attestation that your client completed a real 402→auth→settle→deliver cycle on production infrastructure. Includes @maraventano/map decoder source (src/read.js) inline for URL parsing in future transactions. Use in CI pipelines, before SDK releases, or as agent-to-agent trust anchor. (1 USDC on Base)
• POST /api/mirror — Same as GET /api/mirror. POST accepted so indexers that POST do not get 405 and drop you from their catalogues. (0.25 USDC on Base)
• POST /api/x402-failure-corpus — Same as GET /api/x402-failure-corpus. POST accepted so indexers that POST do not get 405 and drop you from their catalogues. (0.5 USDC on Base)
• GET /api/decode — URL structured-decoder for agents. Pay $0.01 USDC on Base or Solana; pass ?url=<target>; receive typed CleanRead JSON (title, who, what, price, available, payable, outcome) plus Ed25519 attestation. SSRF-guarded fetch; handles product pages, x402 payment challenges, redirects, upstream errors. Failed reads billable with legible reason. For agents wanting to know what's behind a URL before committing to a payment; discovery indexers building typed catalogs; wallet developers testing 402-challenge parsers. (0.01 USDC on Solana)
• GET /api/mirror — Mirror v2 — your x402 client, seen from the merchant seat. $0.25 USDC on Base or Solana. Returns a signed caller-focused report: your_client (requests observed, payment signatures attached, settlements completed, class, verdict ladder (settled / attempted_payment / freeloader / low_signal / unknown)), class_comparison (how you stack up vs peers in your class), diagnostic_recommendations (actionable high/medium severity findings about your observed behaviour), live conformance check on THIS request, and a merchant_window_summary with headline numbers for context. The FULL operator roster is sold separately at /api/x402-operator-census ($0.50). The FULL failure taxonomy is sold separately at /api/x402-failure-corpus ($0.50). Free per-caller preview at /api/mirror/preview. (0.25 USDC on Base)
• POST /api/x402-conformance/self/card — Same as GET /api/x402-conformance/self/card. POST accepted so indexers that POST do not get 405. (0.33 USDC on Base)