Every agent-payable API.

Get full detail (yes/no prices, volume, status, result) for a single Kalshi market by ticker

Returns a Markdown launch kit and seven-day checklist for an x402 service.

Heuristic calls-vs-unique-payers pattern score for the top x402 resources in the CDP Bazaar and PayAI catalogs: per resource price_usdc, unique_payers, calls, wash_risk (low/medium/high) and a reason. No input. A heuristic signal for due diligence before spending, not a finding about any seller. Cached 15 minutes.

Top 3 x402 resources by heuristic calls-vs-unique-payers pattern score from the CDP Bazaar and PayAI catalogs, with host, resource, unique_payers, calls and wash_risk (a heuristic score, not a finding about any seller). No input. Full scored list: /v1/listing-quality ($0.01).

Call before trusting or paying a third-party x402 seller: snapshot one listing from a fixed public directory (payapi, cdp, payai, bazaar) by its id/payTo, or pass ?since= to get told whether it changed since you last saw it. Reads public directories only - never a caller-supplied URL - and returns already-public fields (JSON).

Call before trusting or paying a third-party x402 seller: snapshot one listing from a fixed public directory (payapi, cdp, payai, bazaar) by its id/payTo, or pass ?since= to get told whether it changed since you last saw it. Reads public directories only - never a caller-supplied URL - and returns already-public fields (JSON).

Filter a JSON/NDJSON event log by field/operator/time range; returns matching events. Use when an agent needs to pull matching rows (thresholds, equality, substring, threshold crossings, time windows) out of a log or metrics event list. Body: {events:[...]|"<ndjson>", filter:{field,op,value?,direction?,timeField?,from?,to?,limit?}}. Ops: gt,gte,lt,lte,eq,ne,contains,crosses_threshold. Free demo at POST /demo; docs at /openapi.json.

Base mainnet transaction finality check: given a tx hash, classifies it as not_found, pending, unsafe (sequencer-confirmed only), safe (L1-attested), or finalized (L1-finalized) -- read directly from the node's own safe/finalized block tags, not a modeled reorg probability. Input: tx hash. Output: JSON.

Which x402 sellers actually earn? The top Bazaar sellers on Base ranked by measured revenue or paying wallets: 24-hour and 7-day revenue, payments, unique payers, repeat and returning payer share, top payer share, price range, categories and a likely-wash flag (one wallet doing the volume). Measured from USDC transfers of $5 or less into each seller's payTo on Base, one UTC day at a time, with the day it covers.

The x402 economy in one call: measured daily spend across the top Bazaar sellers on Base, split into organic, likely wash and known samplers/graders, with 7-day totals, the top categories by spend and the top buyer wallets (addresses, labeled when known). Measured from USDC transfers of $5 or less into each seller's payTo on Base, one UTC day at a time, with the day it covers.

One x402 seller's measured revenue and buyers, by host (blockrun.ai) or payTo address: the latest day's revenue, payments, unique and repeat payers, top payer share and wash flags, its 7-day totals, and up to 90 days of daily history. Measured from USDC transfers of $5 or less into each seller's payTo on Base, one UTC day at a time, with the day it covers.

Safelisted read-only JSON-RPC proxy across major EVM chains (base, ethereum, polygon, arbitrum, optimism) — eth_call, eth_getBalance, eth_getTransactionReceipt, eth_getBlockByNumber, and more

Safelisted read-only JSON-RPC proxy across major EVM chains (base, ethereum, polygon, arbitrum, optimism) — eth_call, eth_getBalance, eth_getTransactionReceipt, eth_getBlockByNumber, and more

Use when an agent is about to pay an unknown x402 endpoint and needs a cheap safety gate. Input: url (https x402 resource), method, optional max_price_usd. Output: JSON verdict ALLOW/WARN/DENY with reasons: live quote now, price vs similar routes and your budget, payTo on the OFAC list, price change vs our last measurement, our 7-day uptime/p95, ERC-8004 registration. Never pays; cached 60 s. Example: ?url=https://1gateway.dev/v1/fx/rates&max_price_usd=0.01

Use when an agent or seller must confirm a payment before delivering: checks a Base, Base Sepolia or Solana transaction for a USDC transfer to pay_to of at least amount. Input: tx (hash or signature), pay_to, network (default eip155:8453), optional amount in USDC. Output: JSON paid true/false, verdict, received, payers, block, time, confirmations. Bad formats refused before payment. Example: ?tx=0x…&pay_to=0x…&amount=0.01

The smallest real x402 paid call: costs $0.001 in USDC and returns ok with the server time and payment network. Useful for checking that an x402 client can sign and settle a payment end to end.

The smallest real x402 paid call: costs $0.001 in USDC and returns ok with the server time and payment network. Useful for checking that an x402 client can sign and settle a payment end to end.

Get full detail (prices, volume, liquidity, resolution) for a single Polymarket market by slug

Should an agent pay this x402 endpoint? One read-only call (never pays): validates the 402 + accepts[] (will it settle), labels liveness LIVE|ZOMBIE|DEAD, flags a >=$1000 price-trap honeypot (=> AVOID), scans resource + MCP tools for LLM01/LLM08 injection, screens payTo vs OFAC/scam, checks price (live vs advertised: MATCH|OVERCHARGE|UNDERCHARGE) and Attack-III cache-leakage posture. Returns PAY|CAUTION|AVOID + fix hints. Not a settlement guarantee.

Check an x402 seller before you pay it. Probes the endpoint now, checks that its payment can actually succeed (token EIP-712 domain, payTo), and adds its 30-day uptime from our monitor of paid Bazaar listings, how many distinct buyers paid it, and how its price compares with similar listings, with cheaper well-used alternatives. Returns a verdict (ok, caution, avoid) with the reasons.

Payability preflight: audits an x402 seller's 402 challenge

x402 Price Benchmark what this market actually transact. Hosted API via Speedbot; provider price plus 8% fee. version=external_api_7170e963c4c6254c01805cab2760bdc3 checksum=7170e963c4c6254c01805cab2760bdc35cd68cc75732aec9f7ba1813adaa7409 listing=3c7c58e6983e6f825539d72d4dabbf6ff1c166ad2163d37f1ac4a0c2db32467c

Premium content. Independently monitored by x402-list.com: 100% uptime since Oct 27, 2026, 14/14 x402 compliance checks (as of Oct 31, 2026). Evidence: https://x402-list.com/services/agentx402pay

x402 paywall template for any HTTP API (download). Download the x402 Proxy Template v1.0.0 (zip, MIT): a Cloudflare Worker that puts an x402 paywall (USDC on Base, x402 v2 + v1) in front of any HTTP API from one config file, with Bazaar discovery metadata, OpenAPI, remote + stdio MCP, OpenAPI importer, mock API, smoke test, 11 tests, quickstart and deploy guide.

Live BTC/ETH/SOL prices + the Crypto Fear & Greed Index in one call. Sourced from CoinGecko and alternative.me public data, combined for convenience.

Call before routing or accepting an x402 payment: multi-rail health (facilitators, settlement, market) across x402 rails (JSON).

Call before routing or accepting an x402 payment: multi-rail health (facilitators, settlement, market) across x402 rails (JSON).

On-page SEO audit for any live URL. Returns a 0-100 SEO score plus the raw signals behind it: title tag and meta description with their lengths, canonical URL, robots directives, the full H1-H3 heading map, image alt-text coverage, Open Graph and Twitter card completeness, and whether schema.org structured data is present. Fetches the live page on every call, so results reflect the page as it is now. Use it to audit a landing page, diagnose weak search rankings, or inspect a competitor.

Audit your x402 endpoint before buyers hit it. Checks that it answers 402 on the right method, that the payment options can actually be signed (EIP-712 domain of the token matches extra.name and extra.version), that the resource URL is the https URL buyers call, and that /openapi.json and /.well-known/x402 match. Includes the CDP validate verdict, whether the CDP Bazaar lists the endpoint, its payers in 30 days, and its search rank and competitors' prices for up to 3 queries.

Parameter-free: the Blockchain IQ x402 Conformance Index in one call. The top 1,000 x402 sellers ranked by an A to F grade from our own daily unpaid probe of their listed endpoints: valid HTTP 402, x402 v2, payment terms, schema, 7-day uptime, price range, 30-day payers and calls, with method and sources. Dated each day; never sold when the probe is over 48 hours old. Use to screen endpoints for protocol conformance before an agent pays. JSON, no API key. $0.02 per call. Blockchain IQ.

Use when you sell an API over x402 and want it to pass Bazaar/CDP listing checks. Input: url (https x402 resource), method GET or POST. Output: JSON score 0-100, grade, per-check pass/warn/fail with fix hints (x402 v2 quote, accepts fields, USDC asset, payTo format and OFAC list, description quality, Bazaar schemas, header size, CORS, latency, openapi/llms.txt, ERC-8004) plus our measured uptime. Never pays. Example: ?url=https://1gateway.dev/v1/time/convert

Find the best x402 API for a task. Describe what you need (for example "remove the background from a photo") and get the matching sellers from the CDP Bazaar ranked by relevance, how many distinct buyers paid them in 30 days, their uptime measured by our monitor every 6 hours, and price. Each result has its price, payers, uptime, median latency and how to call it (method and example input).

x402 Service Index the full directory record for live p. Hosted API via Speedbot; provider price plus 8% fee. version=external_api_f1e23f468705020f057cf4cad5af4804 checksum=f1e23f468705020f057cf4cad5af48040228d0cb1eb2f30ac24b1f3e52a8cca5 listing=8bc51cbe53c13640db7ce41d8e544bada0cffc0ef1f61e0ec39ad6d4bdc3b094

x402 Settlement Review: Replay and Double Charge — Reviews pasted seller-side x402 code that accepts the PAYMENT-SIGNATURE header, talks to the facilitator and delivers the goods (the cash register), for the silent failures that double-charge a buyer, hand the goods to a stranger or bill the seller. It flags an expiry check that runs before the nonce lookup, a repeat path that delivers without proof the chain observer lacks, a repeat window taken from the buyer's validBefore instead of the sell…

Real LLM-backed text generation (Gemini), billed by output length (max $0.05/request)

Pay-per-use AI audio transcription API. Transcribe short MP3 and WAV audio files using Whisper Large V3 Turbo. No account or API key required. Pay with USDC on Base. 0.02 USDC per request. Maximum 120 seconds and 2 MB; MP3 and uncompressed PCM WAV only. Returns JSON: text, detected language, duration and timestamped segments. Charged only when a transcript is returned.

Trend insights for a topic, based on real Wikipedia page-view volume and momentum. Premium tier adds relatedTrends: other Wikipedia article titles matching the same search terms (title-similarity, not a curated semantic-relevance ranking). Not literal search/social trend data — see the response's `source` field.

Trend insights for a topic, with a premium tier for the full breakdown

Is this x402 endpoint trustworthy? Body {url}. Returns its latest x402 Trust Index grade (A/B/C) and run date, plus evidence from a real paid test call: 402 status, price seen, payTo, settlement tx hash, on-chain check, HTTP status after paying, latency, schema check, and delivery result. If the endpoint is not in the index you get status not_indexed. Raw data link included. Free grade-only: GET /trust/lookup?url=

Convert a value between units of length, mass, volume, temperature, speed, area, energy, power, pressure, data size, time and more (mathjs units), such as mi to km, degF to degC, GB to MiB, kWh to J.

Run a regular expression on a text: every match with its position and capture groups (named too), and the text with a replacement applied. RE2 syntax, which runs in linear time (no lookaround or backreferences).

Add or subtract an ISO 8601 duration (P1M, P2W, PT36H) to a date, months clamped to the month's end; or count the days, weeks, calendar months, years, seconds and business days (Monday to Friday, less a country's public holidays) between two dates. Also the weekday, ISO week and day of year.

Validate a JSON value against a JSON Schema (draft-07 and 2019-09 keywords, formats such as email, uri, date-time) and list every error with its path. Patterns run on RE2, so a schema cannot stall the check.

Check whether a phone number is valid and possible, find its country and type (mobile, fixed line, toll free and others), and format it as E.164, international and national (libphonenumber metadata).

Holidays of a country (and optionally a state or region) in a year, with date, name and type (public, bank, school, optional, observance), from the date-holidays data for about 200 countries.

Compare two texts by lines, words or characters: what was added and removed, and a unified diff for lines.

Generate random IDs from a cryptographic source: UUID v4, UUID v7 (time ordered), ULID or nanoid, up to 100 at a time.

The current time, or a given time, in one or more IANA time zones, with UTC offset, abbreviation, whether daylight saving time is in effect, and the weekday. Give a local time with from_tz to convert it, handling DST correctly.

Evaluate an arithmetic expression with 64 significant digits (no floating point surprises): operators, parentheses, powers, roots, logs, trigonometry, percentages, constants, units (5 inch to cm) and simple statistics.

Count the tokens of a text for OpenAI models (o200k_base for GPT-4o and later, cl100k_base for GPT-4), with characters, words and lines, to size prompts and estimate cost.