httpay.xyz — 307 Pay-Per-Call APIs via x402 on Base | No API Keys

● healthy ai

307 pay-per-call APIs (287 native + Universal Gateway proxying 37 services) powered by x402 and USDC on Base. Token intelligence, DeFi yields, MEV risk, AI tools, web scraping. No API keys, no subscriptions — pay $0.001–$0.05 per call.

Paid verification

How it works

No sponsored paid call yet.

Pay this endpoint once from your own wallet (Base USDC, up to $1.00) and we call it and record what came back. Your wallet pays the listed recipient directly; Agent Tools never holds funds. Sponsored checks prove delivery; they do not count as demand.

Quality grade

How grading works

A 83.3 / 100

Availability 20.0 / 20

Endpoint responded (HTTP 402)

Payability 15.0 / 15

✓ Answers a real HTTP 402 challenge
✓ Publishes a /.well-known/x402 descriptor
✓ Payment address on record
✓ Settlement network declared
✓ Price declared

Demand 25.1 / 35

125 distinct payers, 5023 USDC transfers in the last 30 days; discounted because most transfers come from few payers

Performance 10.0 / 10

Last probe answered in 142 ms (full marks at 200 ms or less)

Readiness 13.2 / 15

Agent readiness 88/100

Owner verified 0.0 / 5

Nobody has claimed this listing yet

Endpoint last checked 18 h ago. On-chain activity last read 3 d ago. Availability and on-chain demand are both re-probed daily; the grade updates automatically on the next pass. This grade sets search order and leaderboards; the readiness score below is shown for reference only.

x402 readiness

B · 88/100

Readiness is how fully this listing follows its protocol and how it behaved in our probes over 30 days. It is shown for reference and does not move it in search. Search order and leaderboards use the separate quality grade (here A, 83.3/100), which weighs availability, payability and on-chain demand. How the two differ

Valid payment requirements	10/10	Payment requirements carry a payee, a mainnet network and a price.
Live 402 challenge	25/25	Paid endpoint answers with an HTTP 402 challenge (142 ms).
x402 version	5/10	Speaks x402 v1; v2 is current.
Signed descriptor	n/a	No x402 standard defines a signed descriptor.
Uptime (30 days)	15/15	32/32 probes succeeded over 30 days (100%).
Resource declaration	10/10	Declares 180 paid resource(s).
Verified identity	5/10	Publisher descriptor (/.well-known/x402 or OpenAPI) on record; claim this listing to verify domain control.
Freshness + modern flags	5/5	seen in a source within 7 days; declares x402.
Security declaration	n/a	Payment is the access control for an x402 resource.

Applicable criteria total 85 points, scaled to 100.

Responsiveness: Responsive (142 ms; bands ≤2.5 s, ≤5 s, ≤8 s, slower; penalty only).

Payment evidence: x402_challenge — We sent a request and got a live HTTP 402 challenge. Also: x402_manifest, catalog_listing. Qualifies the payment claim; adds no points.

Measured 2026-11-11.

Nine criteria, the same as the A2A readiness score, read from our daily probe of the paid endpoint, its payment requirements and 30-day probe history. Signed descriptor and security declaration are n/a for x402 (payment is the access control), as is an x402 version we have not observed; the remaining points are scaled to 100. Grades: A>=90, B>=75, C>=60, D>=40, F<40. It also feeds 15 points of the x402 quality grade.

Compared with peers

Against 10,082 reachable x402 APIs in our daily snapshot (2026-11-12 06:46 UTC). Display only; it does not change search order.

Readiness: Higher than 85% of peers; This listing 88 · peer median 78
Latency: Faster than 71% of peers; This listing 142 ms · peer median 205 ms

Where it loses the most points, and how to win them back

x402 version −5 — Support the current protocol revision.
Now: Speaks x402 v1; v2 is current.
Verified identity −5 — Claim the listing and prove control of its domain.
Now: Publisher descriptor (/.well-known/x402 or OpenAPI) on record; claim this listing to verify domain control.

How many agent tools actually work · All statistics

Paid endpoints

180 resource(s) advertised by this origin. Each price below is that resource's own x402 price; the headline price is the range across them.

https://httpay.xyz/api/agent-directory $0.0100 / call

Query all ERC-8004 registered agents on Base. Filter by capability, paginate with limit/offset. Returns structured agent list with on-chain data and parsed metadata.

https://httpay.xyz/api/agent-directory-curated $0.0300 / call

Curated static AI agent directory — discover x402-enabled agents and services by capability. See /api/agent-directory for the live on-chain ERC-8004 registry version.

https://httpay.xyz/api/agent-jobs/open $0.0050 / call

List open jobs from the live AgentJobs contract on Base. Params: minPayment (USDC), maxPayment (USDC), sort=newest|payment, limit. Returns live on-chain data.

https://httpay.xyz/api/alpha-report $0.0500 / call

Daily alpha/opportunity report

https://httpay.xyz/api/approval-risk-auditor $0.0050 / call

Approval Risk Auditor — checks a wallet's outstanding ERC20 token approvals for risk. Unlimited approvals to unknown contracts are flagged High risk. Params: ?address=0x...&chain=base. Demo: ?demo=true.

https://httpay.xyz/api/audit-bingo $0.0050 / call

Generate an audit bingo card of common vulnerabilities

https://httpay.xyz/api/base64-decode $0.0010 / call

Decode a base64-encoded string back to text. POST JSON body: {encoded}. Supports standard and URL-safe base64. Uses Node.js built-in Buffer. Zero external dependencies.

https://httpay.xyz/api/base64-encode $0.0010 / call

Base64-encode any text or binary data. POST JSON body: {text}. Returns base64 string and URL-safe variant. Uses Node.js built-in Buffer. Zero external dependencies.

https://httpay.xyz/api/blockchain-mad-libs $0.0020 / call

Crypto-themed mad libs story

https://httpay.xyz/api/bottom-signal $0.0030 / call

Check if we've hit the bottom

https://httpay.xyz/api/bridge-intel $0.0200 / call

Compare bridge routes & costs for Base: Across, Stargate, official Base Bridge. Returns routes sorted by cost. Params: ?from=ethereum&to=base&token=USDC&amount=1000

https://httpay.xyz/api/bridge-rates $0.0100 / call

Compare bridge rates, fees, and speeds across major Base bridges (LI.FI, Stargate, Across, Hop, etc.)

https://httpay.xyz/api/bridge-route-pinger $0.0050 / call

Find the best cross-chain bridge routes for any token transfer. Powered by Li.Fi. Returns top routes sorted by cost (cheapest first). Params: ?fromChain=8453&toChain=1&token=USDC&amount=100. Demo: ?demo=true.

https://httpay.xyz/api/coin-flip $0.0010 / call

Flip a blockchain-verified* coin (*not actually verified)

https://httpay.xyz/api/color-convert $0.0010 / call

Convert a hex color code to RGB and HSL values. Pass ?hex=FF5733 (with or without #). Returns r, g, b, h, s, l values and CSS strings. Uses Node.js built-in math. Zero external dependencies.

https://httpay.xyz/api/contract-audit-scanner $0.0500 / call

Automated smart contract security scanner — checks for reentrancy, oracle staleness, unchecked returns, proxy risks, and more. Returns risk score and actionable findings.

https://httpay.xyz/api/cron-parse $0.0020 / call

Parse a cron expression into a human-readable schedule description. Pass ?expr=<cron-expression> (URL-encoded). Also returns next 5 scheduled run times. Uses the 'cronstrue' npm package.

https://httpay.xyz/api/crypto-achievement $0.0010 / call

Unlock a random crypto achievement

https://httpay.xyz/api/crypto-baby-name $0.0010 / call

Name your baby after crypto (please don't actually)

https://httpay.xyz/api/crypto-band-name $0.0010 / call

Generate a crypto-themed band name

How to call

cURL · x402-fetch / x402-axios will auto-handle 402

curl -sS -i -X GET https://httpay.xyz/api/agent-directory  # expect HTTP 402 Payment Required (about $0.001/call)

/.well-known/x402.json

https://httpay.xyz/.well-known/x402

Listed in

Directories this entry was found in.

awesome-x402 since 2026-05-21 x402scan since 2026-05-22