gold-402

The gold standard for x402 resources. 673 curated entries — paid endpoints probed for a live 402 before listing, libraries and repos checked for real activity, and the whole shelf re-knocked every night with the result dated. No filler. Entries that stop answering move to DEPARTURES.md and keep getting knocked.

gold-402 is small on purpose. A person reads every entry before it goes on the list, and any paid endpoint submitted today has to answer a live 402 before we merge it. We say what we checked and what we didn't.

---

The Directory

The product. 673 entries across 17 shelves, in directory/.

Shelf	What's on it
APIs & Services	Paid endpoints an agent can call. Every one probed for a live 402 before listing.
MCP Servers	Model Context Protocol servers — utility, crypto, security, identity, escrow, discovery.
SDKs & Libraries	Client and server libraries across languages.
Facilitators	Payment verification and settlement services.
Frameworks	Agent frameworks with x402 support.
Tools	CLIs, CI, monitoring, spend controls, testing, discovery.
Security	Audit, risk scoring, pre-execution gates, compliance.
Ecosystem	Protocol, infrastructure, wallets, orchestration, marketplaces.
Aggregators & Proxies	One integration, many upstreams — services that unify or resell access to other providers' APIs and data.
The Global Agent Economy	China, India, Korea — infrastructure no English-language directory indexes.
Learning	Quickstarts, tutorials, reference docs, news.
Community	Channels, newsletters, jobs, events.
Market Data	On-chain analytics, dashboards, adoption.
Examples	Working x402 example projects: full-stack apps, API examples, client examples.
Use Cases & Patterns	Documented x402 deployments and payment patterns, by industry.
Research & Audits	Published studies, security audits and papers about x402, with the method disclosed.
Publisher & Crawler Monetization	x402 pay-per-crawl and publisher paywall tooling and services.

---

What being on this list means

Every entry shows what we know about it:

• A date — the endpoint answered a live 402 when we checked it that day.
• "Listed — no knock receipt" — we read it, but hold no dated check.
• "Listed — no endpoint to knock" — libraries, guides and other resources with nothing to knock.

None of it is a delivery test. A listing means we checked what it says, not that it's worth the money.

---

Ecosystem Data

Numbers we measured ourselves, each with its date, sample size and method. Where measurements disagree, both are shown — they were taken on different days by different methods, and blending them into one tidy figure would be the kind of thing this directory exists to argue against.

Coverage beyond the West

x402 is a US-governed rail. It is not the only answer to machine payment, and outside the West it is not the answer being used — China runs delegated agent authorization on existing rails, India runs regulated human-signed mandates that agents execute inside a cap. Both were operating at scale before the x402 Foundation was a month old.

We index that world too, including surfaces no English-language directory carries: The Global Agent Economy →

---

---

Featured This Month

October 2026 — one pick per shelf. Each shelf opens with its pick and the write-up. Selection is the maintainers' judgment: well-built, actively used, worth a second look. A shelf with no pick that clears the bar runs empty — the empty slot is also a verdict.

Shelf	October pick
APIs & Services	crosscheck accept
MCP Servers	Base toolbox
SDKs & Libraries	x402-dotnet
Facilitators	ArisPay
Frameworks	x402-rails
Tools	ToolMeter
Security	ICME Labs
Ecosystem	Bermuda
The Global Agent Economy	Beckn Protocol
Learning	How x402 paid links work (Payfirst)
Community	Dev.to #x402
Market Data	Dune Analytics x402
Aggregators & Proxies	x402-list

Past features →

---

New This Week

This week (Oct 26—Nov 1)

• Payzum x402 — Hosted no-code x402 proxy that puts a per-call USDC price on Base in front of an existing HTTP API, verifies payment through an external facilitator (currently Coinbase's) and forwards the paid call to the origin with its stored API credential. (Docs)
• Reise-Agent Attest — Ed25519-signed price attestation for travel offers (flights, hotels, ferries, cruises) with a plausibility check before signing, $0.01 USDC on Base mainnet via x402 v2. Example: POST /api/attest {"route":"BER-FCO","travel_date":"2026-11-05","price":"129.99","currency":"EUR","price_scope":"per_person","source":"googleflights-local","source_url":"https://www.google.com/travel/flights","passengers":1}. (Discovery) (llms.txt)
• agent-audit — x402 seller audit, outbound link check, and quote-check APIs on Base USDC at $0.02 / $0.01 / $0.005; example GET /v1/audit?url=https://example.com.
• page-read — Fetches one public URL and returns clean markdown or text for $0.001 USDC on Base; example GET /v1/read?url=https://example.com.
• VerifyPulse — Email deliverability tools for agents: daily SPF, DKIM, DMARC, MX and MTA-STS monitoring with webhook alerts, sending-domain audits, domain age and expiry (RDAP), TLS certificate checks and email-authentication analysis. Single checks free; lists of up to 20 for $0.02 USDC on Base via x402 v2, with the receipt in PAYMENT-RESPONSE. Remote MCP at /mcp.
• Pharos Atlas — Network of 200 specialist sources with stored representations in English (en), Spanish (es), Simplified Chinese (zh), French (fr), German (de), Brazilian Portuguese (pt), Arabic (ar), Hindi (hi), Japanese (ja) and Korean (ko), with navigation across 50 U.S. states to canonical city, neighborhood and landmark records using source-issued slugs and nonempty paginated collections; coverage varies by source and route, and 132 sources have no guide or answer collections; HTML locale selection uses /{locale}/..., while JSON accepts language only where documented and preserves raw geography and provenance; the separate 197 fixed English editorial JSON snapshots have review questions, workflow, subjects and provenance, with this parameter-free offset-printing GET priced at 0.01 native USDC (10000 atomic units) on Base (eip155:8453) via x402 v2; publisher Pharos Atlas / Summerall Capital, rights search=yes, ai-input=yes, ai-train=no, with network inventory and OpenAPI contracts.
• Roundhouse Facilitator — Public x402 facilitator for exact USDC payments on Base mainnet (eip155:8453) via EIP-3009, accepting x402 v1 and v2. Open /verify and /settle with no API key, and the facilitator pays settlement gas. Docs · Test 402 resource.
• agent-exec — Streamable HTTP MCP server with 49 tools: every paid route (sandboxed python3/node execution, durable storage, atomic key claims, signed URL attestations, watches, disposable email, rented DNS, address/URL risk checks, x402 pay-delivery) buyable from $0.001 USDC on Base or Solana, plus 29 free tools (quotes, directory, owner-signed reads, offline x402 verification). (OpenAPI) (Manifest)
• agent-exec — Address and URL risk checks from public risk feeds: verdict, score and reasons, $0.02 USDC flat on Base or Solana, charged only on success. POST /check/address and POST /check/url. (OpenAPI)

Last week (Oct 19—25)

• SAVER Verifier — Source-backed factual claim verification with linked evidence for autonomous AI agents, 0.20 USDC per call on Base via x402 v2; the original /verify remains supported. Example: POST /v2/verify {"claim":"The Earth orbits the Sun."}. (OpenAPI) (Discovery) (GitHub)
• PaperPilot CSV Preflight — Returns structural checks for up to 32 KB of caller-supplied CSV text via POST at 0.005 native Circle USDC per x402 v2 call on Base mainnet.
• VM3 x402 Public Quote Preflight — Performs offline structural checks of caller-supplied unsigned x402 v2 payment quotes for $0.01 Circle USDC per GET on Base, with a free synthetic sample and public source.
• OmniProvider — Pay-per-call LLM chat and cited-brief API for agents: x402 on Base (fixed price, $0.006 to $0.008 USDC) and MPP on Tempo, with a multi-model catalog at /v1/models. Payment settles after the response is produced.
• Argos Bot CTS Bridge API — Provides Arc/Base token mappings, wrapped supply and ownerless Circle CTS bridge verification for 0.005 USDC per lookup through x402 on Base or Arc Gateway.
• Predge — Polymarket data for agents over x402: whale trades of $10,000 or more (15-minute delay), wallet leaderboards, smart-money consensus and ed25519-signed outcome and UMA settlement-risk records, $0.005 to $0.03 USDC per call on Base, Solana, Algorand, Arc or Monad. Example: GET /v1/whales/latest?limit=10. (Docs) (OpenAPI) (MCP)
• Genesis Verify — Independent on-chain payment verification: re-derives a token Transfer from a second Base node and returns HOLDS / FALLS / UNCHECKED per asserted field, with a coverage count (asserted vs compared) and the archive fields it could not read named rather than assumed clean; tx-not-found, pending and node-unreachable come back as dated verdicts, not errors. $0.10 USDC on Base via x402 (POST /verify), plus a $0.01 x402 preflight that checks a 402 is well-formed and names one payTo on Base before you pay (POST /preflight). Example: POST /verify {"chain":"base","tx":"0x…","token":"0x833589…","expect":{"to":"0x…","amount":"1000000"}}. (skill/MCP) (directory)
• x402 Bounty Radar — Provides a $0.01 USDC Base x402 endpoint advertised for ranked developer-bounty discovery with scam filtering and competition scores.
• Checkpoint402 MCP — Remote streamable-http MCP server with five paid data tools plus a free list_services: explain_transaction (any Base or Ethereum tx in plain English), find_defi_yields (risk-tiered pools via DefiLlama), new_token_safety_feed (new tokens with a safety score), sec_8k_company_events (SEC 8-K filings, impact-tagged) and ofac_sanctions_screen (name or wallet against the OFAC SDN list). $0.03–$0.10 USDC per call on Base via x402; errors are never charged. Listed in the official MCP Registry as com.checkpoint402/checkpoint402. Example tool call: explain_transaction {"hash":"0xcbb626797fd53a67c9342c1541bc5e56a447b77a3efe490b5d7b2876be3b7205"}. (Site) (OpenAPI) (Registry)
• GrokBot Base token check — Returns a 0-100 pre-trade risk score for a Base ERC-20 from on-chain reads, $0.01 USDC on Base via x402. (Discovery | OpenAPI)
• Fresh402 — On-demand public-web freshness checks, extraction, deterministic Smart Diff and JSON OpenAPI Contract Diff over REST and remote MCP, with free baseline registration and x402 USDC on Base mainnet ($0.005-$0.020 per paid call); documentation and discovery.
• ROGUE-NET Cited Research — Returns a short research answer for one query, with its sources listed, over a plain GET; $0.10 USDC on Base mainnet (x402 v2, PayAI facilitator) and no account or API key. Example: GET /research/hello. (OpenAPI) (llms.txt)
• MoneySwitch — Self-hosted x402 payer with per-agent spending keys, budget and host limits, revocation, and human approval for payments above a configured threshold.
• Wicked Sanity — Hallucination / claim-check API for agents mid-loop. POST a claim plus context (grounded mode, real HHEM-2.1-Open entailment inference) or let it check live web evidence (open mode, Tavily retrieval scored by the same model) and get supported / unsupported / contradicted / insufficient_evidence with a consistency score and the evidence used, never a guessed verdict. Open mode checks consistency with the web, not objective truth. x402 pay-per-call on Base mainnet via the Coinbase CDP facilitator: $0.003 per request plus $0.001 per grounded claim ($0.015 per open-mode claim), or free with an API key. (llms.txt | OpenAPI | Discovery | MCP)
• agent-exec — Accountless pay-per-use code execution for software agents: POST source code and receive stdout, stderr and exit code from an isolated, network-less sandbox, from $0.0010 per run over x402 on Base or Solana. (OpenAPI) (llms.txt)
• cryptofeed402 — Hyperliquid perp funding (hourly, 8h, annualized), open interest and funding-extreme rank for any listed perp, plus extreme-funding scans, per-asset news sentiment, perp and spot prices, a twice-daily market brief and an agent-readiness audit. Its manifest lists 7 routes, from $0.002 USDC per call on Base, with free sample responses at /samples and an Ed25519-signed receipt on every paid response. Example: GET /perps/BTC. (OpenAPI)
• WebExtract — Web page to clean Markdown or fixed-schema JSON (product price, tables, article metadata), $0.002–$0.005 USDC per call via x402 v2 on Base, Polygon, Arbitrum, Optimism, Avalanche, World Chain and Monad. Example: GET /v1/markdown?url=https://example.com. (Docs) (OpenAPI) (llms.txt)
• Wren x402 Doctor — Free POST /lint checks an x402 v2 402 against the spec and CDP Bazaar listing rules; GET /check?payTo=0x… reports a seller's live Bazaar listings, 30-day calls, payers and estimated delisting dates for 0.10 USDC on Base.
• wren-guard Pro — TypeScript/viem guard for agent wallets (capped, simulated sends; approval, permit and EIP-7702 decoding; injection screen) with an 89-scenario drain corpus and a GitHub Action. GET /sample returns 5 scenarios for 0.01 USDC on Base; GET /buy/19 (or 49, 99) returns a 7-day download link to the kit. MIT core: wren-guard.
• Wren Pre-sign Check — Returns block, review or allow for a transaction or EIP-712 message before an agent signs, flagging unlimited approvals, permits, EIP-7702 delegations and injected instructions; 0.01 USDC on Base per call. POST /check {"tx":{"to":"0x…","data":"0x…"}}; free examples at /demo/<name>.
• Agent Evidence API — MCP server and HTTP API for cited web evidence: initialize and tools/list are free, and each $0.01 USDC x402 call on Base returns source-grounded passages that support, contradict or fail to settle a claim, with source URL, retrieval time and content hash for every excerpt, and no charge when no source is retrieved. (MCP) (GitHub)
• Weather MCP — Hosted MCP server for US National Weather Service data: initialize and tools/list are free, and each tools/call costs $0.01 USDC on Base over x402 for active alerts by two-letter state code or a five-period forecast by latitude and longitude. (GitHub)
• KushBitx AgentProof Quick Check — Checks that Base reports chain ID 8453 and that the official USDC contract has code, returning PASS or FAIL, for $0.001 USDC per call on Base. Example: GET /api/agentproof-quick-check.
• Aomi Task API (staging) — Prepares and simulates an Arc Mainnet transaction intent. A body-bound x402 v2 POST charges 0.01 USDC through Circle Gateway on Arc Mainnet for the preparation attempt; successful nonzero-outflow results require a separate quoted purchase to retrieve the unsigned bundle. Example: POST /v1/task/build {"intent":"Simulate a no-op on Arc Mainnet. Do not sign or broadcast any transaction.","chainId":5042,"sender":"0x000000000000000000000000000000000000dEaD"}. (OpenAPI) (Discovery)
• China Hot Search API — Real-time hot-search lists from 9 Chinese platforms (Weibo, Baidu, Douyin, Zhihu, Toutiao, Bilibili Popular, Bilibili Hot Search, Tencent News, The Paper) in one JSON schema, with $0.01 endpoints for a compact cross-platform top list, a keyword-trending check and Simplified/Traditional + pinyin conversion, plus single board $0.002, all boards $0.005 and cross-platform digest $0.15, USDC on Base via x402 v2. Example: GET /v1/check?q=AI. (OpenAPI) (Sample) (GitHub)
• EDGAR Data API — SEC EDGAR data for agents: company profiles by ticker, recent filings, full XBRL company facts, single-concept time series, cross-company concept frames, and full-text filing search. $0.001–$0.005 USDC per call on Base mainnet via x402 v2 (PayAI facilitator). Example: GET /v1/ticker/AAPL; search: GET /v1/search?q=artificial+intelligence. (OpenAPI)
• Taste Wall Printables Mini — Instant download of three printable wall-art PNGs after x402 payment of 16 USDC on Base mainnet. Example: POST /a/caddy/services/80284581-1470-4a9e-bd87-df29e584b7d6/execute {}. (Storefront)
• VerifFR — French company, EU VAT and address verification: INSEE SIRENE company search and SIRET profiles, VIES VAT validation with a French checksum fallback, and Base Adresse Nationale address normalization. $0.005–$0.01 USDC per GET on Base via x402 v2 and PayAI. Example: GET /api/v1/company?q=TotalEnergies. (OpenAPI) (llms.txt) (Demo)
• SkyeSkiff — Condition-gated rooms for AI agents: each agent signs a wallet challenge and is checked against the room's on-chain conditions and, if the room asks, who it acts for (an ERC-7710 delegation from an accepted principal or an ERC-8004 agent ID) before it joins, gets a signed result, and is removed at a later re-check if it no longer qualifies; $0.50 to open a room, $0.15 per join or re-check, USDC on Base, Polygon, Arbitrum or Solana.
• TapeOut CPU0 Report — Returns pinned-block X Layer TapeOut factory, market fee and genesis processor state as JSON for 0.005 native Circle USDC on Base through x402 v2.
• Open Solid — Agent wallet holding USDC on Base and Solana that pays x402 APIs from the agent's balance within a per-payment limit set by its human owner, alongside a US bank account, prepaid cards and payouts through Laso Finance. (Docs)
• Lumi Trades Vendor Trust — Free 0-100 trust scores for XRPL-payable x402 sellers, built from unpaid 402-quote probes every 30 minutes and daily paid test-buys verified on the XRP Ledger, plus a per-vendor observation report for $0.02 USDC on Base, $0.02 RLUSD/USDC or 0.015 XRP on the XRP Ledger. Free list: GET /v1/trust/vendors; paid report: GET /v1/trust/vendors/{id}/report. (API) (Manifest) (OpenAPI)
• Agent Wallet Index — Index of agent wallets and payment rails, including x402 wallets, with source-linked facts and a REST API and MCP endpoint.
• City Table Clean — Cleans a Socrata or CKAN city open-data CSV by URL (trims whitespace, normalizes headers, ISO dates, plain numbers, de-duplicates rows) and returns the cleaned CSV with a per-cell change log; $0.02 USDC per call on Base mainnet. Example: POST /v1/clean {"url":"https://data.cityofchicago.org/resource/ijzp-q8t2.csv?$limit=100"}. (OpenAPI)
• Weather MCP — Hosted MCP server for US National Weather Service data: initialize and tools/list are free, and each tools/call costs $0.01 USDC on Base over x402 for active alerts by two-letter state code or a five-period forecast by latitude and longitude. (GitHub)
• Agent Evidence API — MCP server and HTTP API for cited web evidence: initialize and tools/list are free, and each $0.01 USDC x402 call on Base returns source-grounded passages that support, contradict or fail to settle a claim, with source URL, retrieval time and content hash for every excerpt, and no charge when no source is retrieved. (MCP) (GitHub)
• Aomi Task API — Production Arc Mainnet service that prepares and simulates an unsigned transaction intent. A body-bound x402 v2 POST charges 0.01 USDC through Circle Gateway for preparation; status polling is free, and nonzero-outflow results require a separate quoted retrieval purchase at 3% of simulated gross outgoing USDC. Aomi does not sign or execute the transaction. Example: POST /v1/task/build {"intent":"Simulate a no-op on Arc Mainnet. Do not sign or broadcast any transaction.","chainId":5042,"sender":"0x000000000000000000000000000000000000dEaD"}. (OpenAPI) (Discovery)

---

---

Quick Start

New to x402? Three steps to your first payment.

1. Pick a facilitator

Use case	Facilitator
Most chains, full SDK support	Coinbase CDP
Edge deployment, global latency	Cloudflare x402
Enterprise billing + disputes	Stripe Machine Payments

2. Install the SDK

# TypeScript
npm install @x402/express @x402/core @x402/evm

# Python
pip install x402

# Rust
cargo add x402-axum x402-reqwest   # x402-rs — see SDKs & Libraries shelf

Checked 2026-09-20. A crate literally named x402 exists on crates.io but is a placeholder with no working code — use x402-rs's crates (x402-axum for servers, x402-reqwest for clients) instead.

3. Add payment middleware

import { paymentMiddleware, x402ResourceServer } from "@x402/express";
import { HTTPFacilitatorClient } from "@x402/core/server";
import { ExactEvmScheme } from "@x402/evm/exact/server";

const facilitator = new HTTPFacilitatorClient({ url: "https://x402.org/facilitator" });
const server = new x402ResourceServer(facilitator)
  .register("eip155:84532", new ExactEvmScheme()); // Base Sepolia testnet

app.use(paymentMiddleware({
  "GET /api/data": {
    accepts: [{ scheme: "exact", price: "$0.01", network: "eip155:84532", payTo: "0xYourAddress" }],
    description: "Paid data endpoint",
  },
}, server));

That's it. The middleware returns 402 with payment details, verifies the client's payment header, and lets the request through.

Full quickstart → · Testnet setup →

---

How x402 Works

1. Client  →  GET /api/data                              (initial request)
2. Server  ←  402 Payment Required                       (payment details in header)
               payment-required: <base64 challenge>       (v2; v1 used X-Payment-Required
                                                           and put the detail in the body)
3. Client  →  EIP-3009 gasless USDC authorization        (client signs only)
4. Client  →  GET /api/data  +  PAYMENT-SIGNATURE         (retry with payment)
5. Facilitator  →  verify + settle on-chain              (~2 seconds)
6. Server  ←  200 OK  +  PAYMENT-RESPONSE                (resource returned)

No gas for the sender. No subscription. No API key. Payment IS authentication.

Protocol spec → · EIP-3009 →

---

Need More?

This README is the front door. The full curated directory — every shelf, every entry — is in directory/.

---

Contributing

gold-402 is curated. Every entry earns its place.

See CONTRIBUTING.md for the curation standard, badge system, acceptance criteria, and submission process.

Quick rules:

• Entry must use the x402 protocol (HTTP 402 + PAYMENT-SIGNATURE), not just USDC or general crypto payments.
• Live URL or public GitHub repo. Link must work.
• Last activity within 12 months (for libraries and resources without a live endpoint).
• One entry per pull request. Format: [Name](url) — Description starting uppercase, ending with period.
• Descriptions are factual. No marketing language.

---

Curated by 24K Labs
_{If this saved you time, star the repo.}

24klabs.ai • x402.org • Protocol Spec • Coinbase Docs • Discord • Live Dashboard