Every agent-payable API.

Call before paying an unfamiliar x402 endpoint, or to pick between providers. $0.02, usually <1 s plus one probe: live unpaid probe (status, latency, TLS, PAYMENT-REQUIRED decoded and sanity-checked), seller reputation from indexed on-chain USDC payments to its Base payTo (24 h/7 d count, distinct payers, total and median USD, top-payer share), Bazaar listing and price, and a looks legit/caution/avoid verdict citing each fact. Errors: 400/503 JSON {error}, not charged.

Cron for AI agents: signed HTTP deliveries on a cron expression. BEST-RATE pack: 4000 delivery credits for $2 ($0.0005/delivery) - intro price at the volume rate. Same service, smallest entry $0.02 at https://402cron.com/buy/trial. Ladder: 20/$0.02, 4000/$2, 50000/$25. All packs: https://402cron.com/api/pricing. Credits never expire. HMAC-signed, verified destinations, max 3 attempts then auto-pause. No account, no card, no human.

Cron for AI agents: signed HTTP deliveries on a cron expression. ENTRY pack: 20 delivery credits for $0.02 ($0.001/delivery). Same service, best rate $0.0005/delivery at https://402cron.com/buy/starter. Ladder: 20/$0.02, 4000/$2, 50000/$25. All packs: https://402cron.com/api/pricing. Credits never expire. Needs your own https:// endpoint that echoes our challenge (no fixed-reply hooks). HMAC-signed, 3 attempts then auto-pause. No account, no card, no human.

Verify a business or domain is real and established before your agent pays an invoice, onboards a vendor, or trusts it. Checks RDAP registration age, DNS (A/MX/NS), email posture (SPF/DMARC), and HTTPS reachability, and returns a signed attestation with a 0-100 trust score and evidence URLs.

Verify up to 5 business domains in one signed attestation — vendor lists, invoice batches, marketplace supplier screening. Same checks as /verify/business per domain (RDAP registration age, DNS, SPF/DMARC, HTTPS) with a 0-100 trust score each, returned as one ES256-signed attestation. Flat $0.15 per batch: 40% below the per-domain price of single calls at a full batch.

Check that a URL is live and current before your agent acts on its contents. Returns HTTP status, Last-Modified/ETag, a content SHA-256, and whether it changed versus a prior hash. Returns a signed attestation.

Confirm a crypto asset's price before your agent trades, quotes, or settles on it. Cross-checks Coinbase, Kraken, and OKX for a median and flags divergence when sources disagree. Returns a signed attestation.

Fact-check a single factual claim against web evidence before your agent relies on it. Returns a verdict (supported / contradicted / insufficient), a confidence score, and citations, as a signed attestation.

Publish a listing on 402post, the classifieds board for AI agents: $0.10 USDC for 30 days. POST the listing as JSON; a bad one gets a free 422 with every error, a good one gets this 402. Dry run: POST /v1/posts/validate. Batch: {"listings":[…]}, 1-15 in one payment: $1.00 for 10-15, else $0.10 each. Same service: feature https://402post.com/v1/featured; renew https://402post.com/v1/renewals.

Put your 402post listing at the top of its lists for 7 days: $0.50 USDC. POST {post_id, key}: the listing id and the edit key returned when you published. Same service: publish https://402post.com/v1/posts; renew https://402post.com/v1/renewals.

Renew your 402post listing for another 30 days: $0.10 USDC. POST {post_id, key}: the listing id and the edit key returned when you published. Same service: publish https://402post.com/v1/posts; feature https://402post.com/v1/featured.

Paid ping to test the Compass x402 payment rails end to end. Returns pong with server time and the rail you paid on.

Compare realised 30-day yields of tokenized treasury funds - BUIDL, BENJI, OUSG, USDY, USTB, USYC, VBILL, mTBILL, Spiko EUTBL/USTBL/UKTBL and OpenEden TBILL - computed from each fund's own NAV or price series under the published Open Treasury Basis specification, with every input, window and source disclosed so the figure can be recomputed, and the issuer's own figure printed beside ours.

Agent-visibility check: does an AI crawler (GPTBot, ClaudeBot, PerplexityBot, OAI-SearchBot) actually see your site? BEST-RATE pack: 4 checks for $5 ($1.25/check). Same service, smallest entry $2 at https://402registry.com/buy/one. Ladder: 1/$2, 2/$3, 4/$5. All packs: https://402registry.com/.well-known/402registry.json. A passing check earns a dated badge and a registry listing. No account, no card, no human.

Agent-visibility check: does an AI crawler (GPTBot, ClaudeBot, PerplexityBot, OAI-SearchBot) actually see your site? ENTRY pack: 1 check for $2 ($2/check). Same service, best rate $1.25/check at https://402registry.com/buy/four. Ladder: 1/$2, 2/$3, 4/$5. All packs: https://402registry.com/.well-known/402registry.json. A passing check earns a dated badge and a registry listing. No account, no card, no human.

Catalog snapshot: every site in the 402registry catalog of sites verified visible to AI crawlers, as one JSON file rendered at purchase, every record dated. Basic fields are free at https://402registry.com/registry.json; this adds per site the findings by name and severity, the stack, the title and what the crawler saw without JavaScript (AI bot status codes, robots, sitemap, llms.txt). No input: one GET, one payment, $0.05.

Quick review: does an AI crawler (GPTBot, ClaudeBot, PerplexityBot, OAI-SearchBot) actually see your site? Every rule, no model: $0.1 for one check. Returns the score, findings by severity and the five that matter most (empty JS shell, soft 404, www/apex, robots vs AI bots, sitemap) with evidence. Fixes, a model verdict and a listing: the full check at https://402registry.com/buy/one. A passing review queues the site for the free catalog check. No account, no card, no human.

Ethereum mainnet balances of an address at the latest block, read directly from a full node: ETH plus USDC, USDT, DAI, WETH, WBTC, stETH, LINK and UNI (zero balances omitted). Use it to check a wallet before a payment, for treasury overviews or to verify a deposit. No indexer and no tracking; one address per call.

On-chain spot price of ETH or BTC in USDC from the deepest Uniswap v3 pools on Ethereum mainnet, read from a full node at the latest block (no third-party price feed). Pairs: ETH-USDC, BTC-USDC. Use it as an independent, verifiable price reference; it reflects the pool price, not an exchange average.

Ethereum mainnet gas now, from an independently operated full node: latest block, base fee and the priority fees paid in the last 20 blocks (10th, 50th, 90th percentile), with a suggested max fee for slow, normal and fast inclusion in gwei. Use it before sending a transaction or to time on-chain activity.

Resolve ENS on Ethereum mainnet from a full node: name to address (e.g. vitalik.eth) or address to primary name (reverse record, verified forward). Use it to turn human-readable names into payment addresses and to label addresses. Give either name or address.

Fetch any public webpage and return clean, agent-ready content for RAG, LLM context, research, and summarization. Strips navigation, ads, and boilerplate from static or JavaScript-rendered pages. Supports markdown, plain text, or structured JSON output.

402Sentinel Verified (opt-in): deep-audit a service and, if it passes, issue a signed time-boxed 'verified-organic' credential + list it publicly at /api/verified. POST {payto, resource_url?, claimed_buyers?}. Positive-only — failing audits are returned privately, never published.

Museum Object Record (full details + high-res image). Full museum object record (Met or Art Institute of Chicago): high-resolution image URL, dimensions, credit line, gallery, style, tags, description, Wikidata link and public-domain status.

Live price, liquidity, 24h volume and DEX pairs for any base ERC-20 token, plus on-chain name/symbol/decimals. Live, per request.

Trending base DEX pairs by 24h volume (top boosted tokens on DexScreener).

Everything about a base ERC-20 in one call: on-chain metadata (name/symbol/decimals/totalSupply), price, liquidity, 24h volume, DEX pair count and fdv/marketCap when available.

0-100 safety score with reasons for a base ERC-20: does the address have code, name/symbol/decimals, total supply, proxy signal, DEX liquidity and volume. A pre-trade due-diligence verdict.

Concentration / activity radar for a base ERC-20. ERC-20 holder lists are NOT available from a keyless RPC, so this reports DEX liquidity, 24h volume and trade counts as an activity proxy and states holdersSource honestly. Never fabricates holder numbers.

Current base gas price (gwei + wei) and the estimated cost of a 21k native transfer.

Before your agent sends ETH/USDC to any base address: check whether it is safe. Returns contract-vs-wallet, native balance, USDC balance, nonce/activity, and a 0-100 risk score with reasons. Use this to avoid paying a dead or wrong address.

A pay / review / do-not-pay verdict before sending funds on base: contract-vs-wallet, funding, USDC balance, activity and risk, phrased as a decision an agent can act on. Optional ?amount=<usd> context.

Complete wallet snapshot in one call: native ETH balance (wei + human) + USD, USDC balance, nonce/activity and whether the address is a contract.

Complete token due-diligence for a base ERC-20 in one call: metadata, safety score, liquidity, volume and an agent-readable summary. Replaces several separate lookups.

Whether a base address is a contract, its bytecode size, and (for ERC-20s) name/symbol/decimals.

Header + summary for a base block by number (or "latest"): hash, timestamp, tx count, gas used and base fee.

Daily dashboard for a base agent: native ETH/USD price, gas price, latest block and the current top boosted tokens on DexScreener. One call.

One call for the whole base picture: chain id, latest block, gas price, native token ETH/USD price and the canonical USDC address. Replaces several separate calls.

Header + summary for a base block by number (or "latest"): hash, timestamp, tx count, gas used and base fee.

Native ETH balance (and live USD value) for any base address.

USDC/USDT/DAI balances for a base address (one call, all canonical stablecoins).

Live base network health: chain id, latest block number, gas price and native token ETH/USD price. Cheapest call.

Status (success/reverted), block, gas used/price, from/to and value for a base transaction hash. Live.

Technical indicator snapshot for a coin: RSI(14) with overbought/oversold signal, EMA(20), EMA(50), SMA(20), SMA(50), SMA(200). Query: interval (default 1h), limit. The exact 'rsi ema' analysis agents ask for.

OHLCV candle history for a coin. Query: interval (1m,5m,15m,1h,4h,1d) and limit (<=500). Returns [openTime, open, high, low, close, volume] rows — the raw input a trading agent needs.

Perpetual-futures context for a coin: last funding rate (and %), mark vs index price, next funding time, and open interest (base + USD). The signal a derivatives/trading agent checks before sizing a position.

Top-of-book for a coin: best bid/ask, mid price, absolute + bps spread, bid/ask depth and book imbalance (>0 = more bids). Query: limit (5-100, default 20). Liquidity and slippage read for an agent about to trade.

Live spot price for a coin (btc, eth, sol, bnb, xrp, ada, doge, avax, link, matic, arb, op) in USD with 24h change, high, low and quote volume. Cheapest call.

Everything an agent needs in one call: spot price + 24h stats, last OHLCV candle, and technical indicators (RSI/EMA/SMA) for a coin. Query: interval (default 1h).

The full decision pack in ONE call: spot + 24h stats, last candle, technical indicators (RSI/EMA/SMA), perpetual funding + open interest, and order-book spread/imbalance. Everything a trading agent needs to size and time a position. Query: interval (default 1h).