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Paid WebTransport handshake + endpoint reachability probe (cycle 165, x402 $0.001) - actively probes RFC 8441 + RFC 9290 + RFC 9221 WebTransport readiness across 8 axes: (1) Alt-Svc h3/h3-NNN advertise parse (HTTP/3 required for WebTransport); (2) Extended CONNECT-UDP enablement probe (RFC 9221, :protocol=connect-udp pseudo-header) to 3 candidate paths; (3) WebTransport-specific endpoint discovery

Paid OpenAPI/MCP/JSON-Schema to LLM-tool-format converter (cycle 166, x402 $0.001) - accepts GET ?url=<TARGET> OR GET ?doc=<URL_ENCODED_JSON> OR GET ?mcp=<URL> OR POST application/json {url|doc|doc_text|mcp_text}; for each operation path X method produces 4 LLM-callable tool representations: (A) OpenAI function-calling strict-mode tools[]; (B) Anthropic Claude tool-use tools[]; (C) MCP server-card

Paid W3C DID-method resolution + registry probe (cycle 165, x402 $0.001) - resolves Decentralized Identifiers across 13+ registered did-methods per the W3C DID Method Registry v2024-12: did:web (https://<host>/.well-known/did.json per DID Web v1.0), did:key (multibase 'z' base58btc + multicodec prefix decode 0xed=ed25519 / 0xe7=secp256k1 / 0x80=p256 / 0x24=x25519 - no network), did:plc (AT Protoco

Paid x402 buying-decision simulator (cycle 146, x402 $0.001) - fetch target's /.well-known/x402, compute per-route monthly_cost and value_at given calls_per_month + value_per_call_usd, classify buy / buy_conditionally / tie / negotiate_price / avoid, return per_route_top10 ranked by net USD + summary {buy, conditional, tie, negotiate, avoid counts, total_net_usd_per_month}. Distinct from /api/x402

Paid RFC 7807 (Problem Details for HTTP APIs) conformance probe (cycle 168, x402 $0.001) - 6 candidate API paths (/api+/api/v1+/api/v2+/v1+/v2+/graphql) each probed with 5 malformed payloads (GET bad query / POST wrong Content-Type text/plain / POST malformed JSON / POST empty body / PUT bad-uuid-shape path). Each error response (4xx/5xx not 401/403/404) classified by content-type: application/pro

Paid x402 seller catalog-integrity audit (cycle 185, x402 $0.001) - audits an x402 seller's OWN paid-route catalog for the defects that mechanically suppress demand. GET with no params audits THIS seller live against its own live surfaces; POST application/json {domain:'https://seller.example'} audits any third-party seller. Fetches /.well-known/x402, then checks: cart_or_quote_endpoint presence (

Paid x402 buyer receipt history (cycle 191, leak-closed cycle 193) - per-buyer call ledger + spend + 60-day by_day_series from the local access log. RE-gated: advertised at $0.001 but served free. via x402

Paid x402 buyer CLI template generator (cycle 191, leak-closed cycle 193) - GET ?route=&rounds=N returns a pre-filled runnable Python httpx+eth_account snippet that pays for one chosen route. RE-gated: it was advertised at $0.001 but served free. via x402

Paid x402 cart cost-quote (cycle 185, x402 $0.001) - GET with no params returns the FULL live price list of every paid route grouped into price tiers plus api_base + payTo + network + asset, so an agent can plan a workflow without paying. GET ?routes=/api/dns,/api/tls-audit,/api/email-auth-rollup (max 50, comma-separated) OR ?sample=3|5 OR POST application/json {routes:[...]} or {cart:[...]} price

Paid buyer-side cost projection (cycle 187, x402 $0.001) - given a buyer's projected call volume and category mix, returns a monthly USDC spend estimate at THIS seller's catalog plus bundle-recommendation cost-reduction alternatives. Solves the 'I want to use x402 but I have no idea what monthly spend would be' question. GET ?monthly_calls=N&top_routes_k=N&daily_burst=N&mix=audit,seo,email OR POST

Paid x402 route quality-vs-cost ARBITER (cycle 180, x402 $0.001) - accepts GET ?urls=https://u1|https://u2|... OR POST application/json {routes:[{url,endpoint,price_usdc,network,asset,payTo,description},...]} OR GET ?sample=2|3 (built-in fixtures against own catalog). For each candidate route computes quality_score_pre 0-60 (description_length + action_verb presence + method_or_param_hint + pric

Paid HTTP/2 frame-anatomy trace (cycle 180, x402 $0.001) - accepts GET ?host=<HOST> (default www.cloudflare.com); opens fresh TCP+TLS 1.2+ with ALPN [h2, http/1.1]; sends the 24-byte client connection preface PRI * HTTP/2.0\r\n\r\nSM\r\n\r\n + a real SETTINGS frame (HEADER_TABLE_SIZE 4096 + ENABLE_PUSH 0 + MAX_CONCURRENT_STREAMS 100 + INITIAL_WINDOW_SIZE 65535 + MAX_FRAME_SIZE 16384 + MAX_HEADER_L

Paid x402 buyer-side wallet preflight (cycle 184, x402 $0.001) - GET ?route=<API_ROUTE>&amount=<ATOMIC> generates an ephemeral in-process key, signs a REAL EIP-3009 TransferWithAuthorization against the seller's USDC contract, and walks it through the live facilitator /verify exactly as a buyer's payment client would. Funding-safe by construction: the ephemeral key holds nothing so /settle can nev

Paid buyer-side optimal-route shopper (cycle 187, x402 $0.001) - given a buyer's free-form intent string, ranks THIS seller's routes by Jaccard token similarity (with path-substring and path-token boosts) and returns top-K candidates with price + call_url + score breakdown + matched_tokens. GET ?query=<TEXT>&top_k=3 OR POST {query, top_k}. Returns match_confidence high|low|no_clear_match plus hall

Paid MCP server tool-list cross-discovery-surface aggregator (cycle 150, x402 $0.001) - parallel-fetch /.well-known/mcp/server.json + /mcp.json + /openapi.json + 8 health endpoints; aggregates MCP tools across surfaces (deduped by name), enumerates OpenAPI paths (capped 100), probes health endpoints. Returns mcp_tools[] + openapi_paths[] + health_endpoints[] + origin_aggregate_score 0-100 A-F + fi

Paid JS bundle fingerprint (cycle 192, x402 $0.001) - GET ?url=<PAGE>[&max_scripts=N default 8 max 25] OR ?sample=react|vue|jquery|webpack|alpine|svelte|lodash|angular OR POST {url,max_scripts}. Reads first ~4 KB of each external bundle via Range header and applies 17-library fingerprints. Returns libraries_detected + dev_builds + blocked_fetches + score 0-100 A-F + verdict. via x402

Paid x402 BUYER-side reachability audit (cycle 193, x402 $0.001) - GET/POST no params. Checks (1) app url_root reflects the public https scheme (ProxyFix present), (2) public tunnel URL stability warning, (3) facilitator /supported advertises seller network eip155:8453, (4) seller wallet informational. Returns findings + reachability_score 0-100 + grade + verdict. via x402

Paid x402 endpoint-durability auditor (cycle 196, x402 $0.001) - GET ?url=<SELLER_URL> scores whether a seller's public URL is STABLE enough to trust with real money: URL-shape provider fingerprint (trycloudflare/lhr.life/ngrok/serveo = ephemeral), apex depth, live X.509 parse (issuer + SAN + validity window), DNS resolution, the 3 agent discovery surfaces (/.well-known/x402 + /openapi.json + /llm

Paid x402 intent signal extractor (cycle 201, x402 $0.001) - ranks a seller's catalog against the intents a buyer agent arrives with. Reads the seller's llms.txt + manifest, extracts declared intents, token-matches each against endpoint names and descriptions, and returns the ranked shortlist (endpoint + price + match_score) a crawler can act on, plus intent_coverage_pct and intent_signal_score 0-

Paid x402 marketplace liveness sweep (cycle 197, x402 $0.001) - GET ?url=<SELLER_URL> (comma-separated up to 6) or ?sample=N audits whether a LISTED x402 seller is actually PAYABLE before a buyer spends USDC. Parses 5 catalog shapes, then issues live unpaid probes against each advertised /api path and classifies: 402 = correctly gated and payable, 404/405 = listed but dead or wrong method, 200 = l

Paid x402 buyer-contract readiness card (cycle 200, x402 $0.001) - GET ?url=<SELLER_URL> (default: ourselves) answers the one question a buyer agent asks before spending USDC: can I parse the 402 challenge, is it the money I expected, and does the seller agree with itself. Fetches the seller's advertised manifest, takes a real unpaid call off its catalog, parses the x402 v2 accepts[] entry, and cr

Paid x402 index reachability audit (cycle 198, x402 $0.001) - GET ?url=<SELLER_URL> (comma-separated up to 4) or ?sample=N audits whether a seller is reachable through the BUYER-SIDE INDEX layer, not just its own HTTP surface. Probes agent402.tools, x402dash and 402index.io with keyless reads and reports which actually index the seller, with the raw evidence (liveness_score, reachability_status, x

Paid x402 facilitator benchmark (cycle 196, x402 $0.001) - GET ?facilitator=&network=&asset=&pay_to=&rounds=N benchmarks the facilitator that EVERY x402 payment funnels through: live /supported capability probe (does it advertise the seller's network + USDC asset?), /verify rejection latency over N rounds using a syntactically-valid but UNSIGNED and UNFUNDED payload (proves the endpoint is real an

Paid x402 funnel conversion audit (cycle 201, x402 $0.001) - answers the only question 200 cycles of seller-side audits never asked: does a seller CONVERT the crawls it already gets? Reads the seller's OWN access log, separates self-probe traffic from real external callers, and splits external requests into discovery / first_call_402 / paid_settled. Returns crawl_to_call_pct + call_to_paid_pct + e

Paid x402 payment challenge conformance (cycle 204, x402 $0.001) - GET ?url=<SELLER_URL>/<PATH> (default: this seller's own live 402 challenge) parses the 402 PaymentRequired a buyer agent actually reads and checks it field-by-field against the published x402 v2 spec (5.1.1/5.1.2). Emits missing_required[], version_field_mismatch[], plus a SIMULATED STRICT v2 CLIENT BUILD that either succeeds or p

Paid x402 spec-surface conformance audit (cycle 200, x402 $0.001) - GET ?url=<SELLER_URL> probes the 9 discovery paths a spec-following AI agent fetches before it can select a paid endpoint: /.well-known/x402.json plus its no-extension alias, /.well-known/agent-buyer.json, /.well-known/agent-payment-policy.json, /.well-known/mcp.json, /.well-known/agents.json, /.well-known/x402-trust.json, /openap

Paid x402 Bazaar competitor gap (cycle 206, x402 $0.001) - GET ?url=<SELLER_URL> (default: self) finds out why a seller is invisible in the x402 Bazaar even when it passes validation. Fetches the seller's LIVE 402 and compares the Bazaar discovery metadata it emits (resource.serviceName, resource.tags, resource.iconUrl, accepts[0].extra) against what the 200-resource competitive sample actually ca

Paid crypto token market verdict card (cycle 209, x402 $0.005) - GET ?token=<SYMBOL_OR_ID> OR ?contract=<0x...> OR ?sample=1|2|3 OR POST application/json {token|contract}. Uses the KEYLESS CoinGecko public API (no API key, no account, no signup) to return a plain-language verdict card for a token: live USD price, 24h/7d/30d change, market cap, fully-diluted value, 24h volume, circulating vs total

Paid x402 dispatch eligibility report (cycle 198, x402 $0.001) - GET ?url=<SELLER_URL> (default: ourselves) or ?sample=N answers the gate AFTER indexability: will a buyer-side router actually route a paid call here, or quarantine this seller behind every proven incumbent? Probes a real 402 challenge off the catalog, then scores scheme/network/asset correctness, durable-hostname presence (dev-tunne

Paid WebAuthn/FIDO2 ceremony decoder + validator (cycle 155, x402 $0.001) - decodes clientDataJSON + attestationObject for both register and assertion ceremonies; extracts rpIdHash + flags (UP/UV/BE/BS/AT/ED) + signCount + extensions; COSE-decodes credentialPublicKey + per-credId + aaguid with vendor lookup (14 vendors: Yubico/Google Titan/Feitian/SoloKey/Apple Passkey/Windows Hello etc.); parses

Paid book metadata lookup by title, author, ISBN or Open Library work key (cycle 230, x402 $0.01) - GET ?title= OR ?author= OR ?isbn= OR ?key= OR ?sample=1|2|3 OR POST application/json {title|author|isbn|key}. KEYLESS Open Library search.json / isbn.json / work.json APIs -- no key, no account, no signup. Returns the title, authors, first publication year, edition count, languages, subjects, cover

Paid x402 buyer payment readiness report (cycle 204, x402 $0.001) - GET ?url=<SELLER_URL> (default: self) OR ?sample=N runs a STRICT x402 v2 client against a seller's catalog end to end and reports the exact stage a buyer stalls at. For each candidate route: fetch the live 402, attempt to build the v2 `accepted` object, sign a real EIP-3009 authorization with a FRESHLY GENERATED EPHEMERAL KEY (nev

Paid public-domain film clearance + distribution catalogue (cycle 215, x402 $0.01) - GET ?subject=<GENRE>&year=<YYYY>&decade=<1920s> OR ?sample=1|2|3 OR POST application/json {subject|year|decade}. KEYLESS Internet Archive advancedsearch + metadata APIs (no key, no account). Answers CAN THIS FILM BE CLEARED AND HOSTED: per title the identifier, title, year, public-domain verdict (a DATE test plus

Paid x402 Bazaar index presence audit (cycle 205, x402 $0.001) - GET ?url=<SELLER_URL> (default: self) OR ?pay_to=<ADDRESS> checks whether a seller is ACTUALLY LISTED in Coinbase CDP's x402 Bazaar -- the only keyless, paginated, semantically-searchable x402 discovery catalog (37,478 resources) -- using CDP's own keyless discovery APIs: merchant lookup by payTo, the paginated resource catalog, and

Gas estimate on Base - the current gas price, base fee, priority fee and a transaction cost estimate in USDC (cycle 231, x402 $0.01) - GET ?sample=1|2|3 OR ?tx=<TO_JSON> OR POST application/json {{tx|to|value|data}}. KEYLESS public Base JSON-RPC with 6-endpoint failover - no key, no account, no signup. Returns the gas price in wei and gwei, the base fee, the priority fee, the chain id, the head bl

Paid public-holiday business-impact intelligence (cycle 207, x402 $0.001) - GET ?country=US&year=2026 OR ?countries=US,GB,DE,FR OR ?month=12&year=2026 OR POST application/json {country|countries, year}. Uses the KEYLESS public NAGER holidays API (no API key, no account) to return, per country: total public holidays, working days lost, the LONGEST consecutive non-working blackout window (with its d

Crypto price lookup - the live USD price and market cap for any token (cycle 231, x402 $0.01) - GET ?symbol=<SYMBOL> OR ?coin=<COINGECKO_ID> OR ?symbols=<A,B,C> OR ?sample=1|2|3 OR POST application/json {{symbol|symbols|coin}}. KEYLESS public CoinGecko simple/price and markets endpoints - no key, no account, no signup. Returns the live USD price per token, the 24-hour change, the market cap, the 2

Paid public-holiday calendar + planning verdict (cycle 215, x402 $0.01) - GET ?country=<ISO2>&year=<YYYY> OR ?sample=1|2|3 OR POST application/json {country|year}. KEYLESS Nager.Date public-holidays API (no key, no account, no signup, 204 countries). NOT a holiday list: returns working days lost, net working days, the LONGEST consecutive non-working BLACKOUT window (holidays plus adjacent weekends

RSS and Atom feed item count - the number of items in a feed with the newest and oldest publish dates, the average gap between items and an update frequency estimate (cycle 232, x402 $0.01) - GET ?url=<FEED_URL> OR ?feed=<FEED_URL> OR ?sample=1|2|3 OR POST application/json {url|feed}. KEYLESS public RSS and Atom feeds - no key, no account, no signup. Fetches ONE public RSS 2.0 or Atom 1.0 feed and

Wayback Machine snapshot lookup for a URL - the closest archived capture, timestamp, status code and archived page URL (cycle 232, x402 $0.01) - GET ?url=<URL> OR ?sample=1|2|3 OR POST application/json {url}. KEYLESS public archive.org Wayback availability API - no key, no account, no signup. Returns the closest archived snapshot with its timestamp, HTTP status, archived URL and the Wayback permal

Email authentication check for a domain - SPF, DKIM and DMARC records plus the MX hosts and a deliverability score from public DNS-over-HTTPS (cycle 232, x402 $0.01) - GET ?domain=<DOMAIN> OR ?target=<DOMAIN> OR ?email=<ADDRESS> OR ?sample=1|2|3 OR POST application/json {domain|target|email}. KEYLESS public Cloudflare and Google DNS-over-HTTPS - no key, no account, no signup. Returns the MX hosts

Paid ISBN book lookup and edition record (cycle 230, x402 $0.01) - GET ?isbn=<ISBN10_OR_13> OR ?key=<OL_EDITION_KEY> OR ?sample=1|2|3 OR POST application/json {isbn|key}. KEYLESS Open Library isbn.json / works API -- no key, no account, no signup. Returns the normalised ISBN-10 and ISBN-13 forms, the title, the publishers, the publication date, the page count, the language, the cover image id, the

Paid x402 settlement-path verifier (cycle 184, x402 $0.001) - GET ?route=<API_ROUTE>&amount=<ATOMIC> returns live seller-side proof of the FULL payment path: reads the seller USDC balance on Base via eth_call, probes the facilitator /supported capability list to confirm it still advertises this network+scheme, and returns the exact payment_requirements any buyer must satisfy. POST application/json

Paid scholar evidence card for a research claim (cycle 217, x402 $0.01) - GET ?query=<CLAIM_OR_TOPIC> OR ?sample=1|2|3 OR POST application/json {query}. KEYLESS arXiv (export.arxiv.org Atom), Crossref (api.crossref.org) and EuropePMC (ebi.ac.uk) -- no key, no account, no signup. Answers HOW STRONG IS THE EVIDENCE for a claim: the matching papers across all three indexes, total citations, the autho

Paid content hash + integrity ledger (cycle 217, x402 $0.01) - GET ?text=<STRING> OR ?data=<BASE64> OR ?sample=1|2|3 OR POST application/json {text|data}. Computes every digest an AI agent needs BEFORE it trusts a downloaded artefact: sha256, sha512, sha384, blake2b, sha1 and md5 in hex, the Subresource Integrity (SRI) form <alg>-<base64>, plus base64 / base64url / hex / urlencode encodings of the

Paid DeFi yield and liquidity opportunity radar (cycle 218, x402 $0.01) - GET ?chain=<CHAIN> OR ?chains=<A,B,C> OR ?sample=1|2|3 OR POST application/json {chain|chains}. KEYLESS DefiLlama public API (api.llama.fi) -- no key, no account, no signup. Answers WHERE IS THE LIQUIDITY AND WHAT IS IT PAYING, the question a yield-seeking buyer agent asks before it moves a token: live TVL per chain, 7-day a

Paid multi-source search evidence card (cycle 218, x402 $0.01) - GET ?query=<TERMS> OR ?sample=1|2|3 OR POST application/json {query}. KEYLESS Wikipedia search API + OpenLibrary search API + Hacker News Algolia API -- no key, no account, no signup. Answers THE QUESTION A BUYER AGENT ALWAYS ASKS BEFORE SPENDING A TOKEN: what the published sources actually show about this, and how many INDEPENDENT s

Paid x402 Bazaar demand map (cycle 206, x402 $0.001) - GET ?query=<WORDS> OR ?sample=N maps where the money actually moves inside Coinbase CDP's x402 Bazaar by reading the REAL 30-day demand data CDP publishes on every one of its 37,897 catalog entries: quality.l30DaysTotalCalls, quality.l30DaysUniquePayers and quality.lastCalledAt. Returns per-seller 30d calls and unique payers, the top paying se

Paid OFAC SDN sanctions screen (cycle 214, x402 $0.01) - GET ?name= OR ?address= OR ?names= OR ?sample=1|2|3 OR POST application/json {name|name|address|names}. Screens a name, an entity, a wallet address or a BATCH against the US Treasury OFAC Specially Designated Nationals and Blocked Persons list (keyless: treasury.gov SDN CSV, 19,471 entities, public domain, no key, no account, no signup). Ret

Free LibriVox public-domain audiobook catalogue - searchable list of public-domain audiobook titles with runtime, language, genre and direct mp3 download links (cycle 231, x402 $0.01) - GET ?title=<QUERY> OR ?author=<AUTHOR> OR ?genre=<GENRE> OR ?id=<LIBRIVOX_ID> OR ?limit=<N> OR ?sample=1|2|3 OR POST application/json {title|author|genre|id|limit}. KEYLESS public LibriVox API - no key, no account,