APIs your agent can pay for by the request.
No API keys, no signups, no subscriptions. Every route here is metered in USDC — call it, get an HTTP 402 with the price, sign a payment, and the data comes back. Built on the open x402 protocol.
Gold Source Indexing Agent
Send a document as text, a public URL, or a file upload (plain text, HTML or PDF). You get back a section tree that points to the exact source text instead of rewriting it: every section and block has a [start, end) span, its section path and a SHA-256 fingerprint, plus a coverage check that shows whether any text was left out.
- Text, HTML or PDF
- URL or file upload
- Exact [start, end) spans
- SHA-256 per node
- Coverage check
- Stateless
curl -X POST https://agentx402pay.com/api/gold-index \
-H "Content-Type: application/json" \
-d '{"text":"SERVICES AGREEMENT\n\nARTICLE 1 - SERVICES\nProvider will deliver the Services described in Exhibit A.\n\nARTICLE 2 - FEES\nClient pays $2,500 per month, due within 30 days of invoice.\nLate amounts accrue interest as set out in Section 2.3.","filename":"services-agreement.txt"}'{
"goldMeta": {
"hash": "2ab4a039efcc241763219a21f101fb51ffaec73696f0e3fd99f1c3ed01122f01",
"offsetUnit": "utf16-code-unit",
"nodeCount": 5,
"coverage": {
"indexedNonWhitespaceChars": 193,
"totalNonWhitespaceChars": 193,
"complete": true
}
},
"tree": {
"children": [
{
"type": "SECTION",
"title": "ARTICLE 1 - SERVICES",
"sectionPath": [
"ARTICLE 1 - SERVICES"
],
"goldPointer": {
"start": 20,
"end": 40,
"fullTextHash": "6a75606bef13f06ed6132c6c61a547351eb8d83cad12eaa20a2cce95608f1616"
}
},
"…"
]
}
}Pay from whatever chain you already hold USDC on
19 of the 21 routes on this page take payment on all four networks and work the same way on each: sign, retry, get the response. As of August 2026 that includes Ethereum's two largest L2s alongside Base, plus Solana for the non-EVM path. The other 2, /api/generate and /api/ping, take Base only. One address per chain family, same USDC price everywhere.
Coinbase's L2 — the original network every route here shipped on.
High-volume, low-fee settlement — added August 2026.
Optimistic-rollup throughput — added August 2026.
Sub-second finality — the non-EVM option, wired since launch.
x402 doesn't just run on this server
This is real, live activity across the whole x402 ecosystem — every seller, every facilitator — not just traffic to AgentX402Pay. The same open protocol every route on this page speaks.
Live · x402 protocol, every seller
Real ecosystem-wide activity — not just this server. Data via agentic.market.
Three requests, no dashboard
x402 turns HTTP 402 Payment Required from a dead status code into a working payment flow. There's nothing to configure before your first call. Scroll to watch each step highlight the matching part of the exchange.
Call the endpoint
No payment attached, so the server replies 402 with the exact price and payment instructions.
Sign a payment
Your wallet (or agent's x402 client) signs a USDC payment for that exact amount — no on-chain transaction yet.
Retry and get paid data
Resend the request with the signed payment attached. The payment is verified, the route runs, and the response comes back.
Payment flow
Follows the step you're reading.
Everything this server sells
Every route below prices in USDC, settles only after a successful response (a request that fails is not charged), and declares Bazaar-compatible discovery metadata. All take GET requests except /api/gold-index, which takes the document in a POST body.
Flagship examples
6Each demonstrates a different x402 payment pattern — fixed price, usage-based, dynamic pricing, and payment channels.
A whole paid page, not a JSON API — same per-route x402 gating as every other endpoint.
No query params required.
https://agentx402pay.com/protected
Live current weather for any city, sourced from Open-Meteo.
- city= Austin
https://agentx402pay.com/api/weather?city=Austin
Buyer authorizes a max in one signature; you charge only for the output actually generated. Base only.
- prompt= explain x402 in one paragraph
https://agentx402pay.com/api/generate?prompt=explain%20x402%20in%20one%20paragraph
Topic attention from Wikipedia page views: 7-day average, week-over-week change and peak day. Premium adds the daily series, spikes and related topics.
- tier= premium
- topic= ai agents
https://agentx402pay.com/api/insights?tier=premium&topic=ai%20agents
Cheap repeatable calls accumulate in one payment channel, settled on a schedule instead of per-call. Base only.
No query params required.
https://agentx402pay.com/api/ping
Indexes a document without rewriting it: exact [start, end) text spans, section paths and SHA-256 fingerprints, plus a coverage check.
POST JSON {"text": "..."} or {"url": "..."}, a text/plain body, or a multipart "file" (text, HTML or PDF)
No query params required.
https://agentx402pay.com/api/gold-index
Data endpoints
11Prediction markets, DeFi, crypto market data, and web search — the categories driving the most real usage across the x402 ecosystem today.
Search/list Polymarket prediction markets by volume
- q= election
- limit= 10
https://agentx402pay.com/api/polymarket-markets?q=election&limit=10
Single Polymarket market detail by slug
- slug= will-btc-hit-100k(required)
https://agentx402pay.com/api/polymarket-market?slug=will-btc-hit-100k
Search/list open Kalshi prediction markets
- q= fed
- limit= 10
https://agentx402pay.com/api/kalshi-markets?q=fed&limit=10
Single Kalshi market detail by ticker
- ticker= FED-24DEC(required)
https://agentx402pay.com/api/kalshi-market?ticker=FED-24DEC
DeFi protocol TVL, by chain + market cap
- protocol= aave(required)
https://agentx402pay.com/api/defi-tvl?protocol=aave
Rank blockchains by total DeFi TVL
- limit= 15
https://agentx402pay.com/api/defi-chains?limit=15
Price + 24h change for one or more coins
- ids= bitcoin,ethereum(required)
- vs= usd
https://agentx402pay.com/api/crypto-price?ids=bitcoin%2Cethereum&vs=usd
Rich market data: rank, volume, ATH, and more
- ids= bitcoin,ethereum(required)
- vs= usd
https://agentx402pay.com/api/crypto-market?ids=bitcoin%2Cethereum&vs=usd
Top trending cryptocurrencies right now
No query params required.
https://agentx402pay.com/api/crypto-trending
Real ranked web search (Exa): title, URL, published date, relevance score
- q= Base blockchain(required)
- numResults= 5
https://agentx402pay.com/api/web-search?q=Base%20blockchain&numResults=5
Same question priced differently on Polymarket and Kalshi, checked for matching outcome, numbers, dates and wording, with live quotes and hedge edge. No match, no charge.
- q= election
- limit= 10
- minDivergencePct= 10
https://agentx402pay.com/api/prediction-arb?q=election&limit=10&minDivergencePct=10
On-chain data
4Multi-chain reads across Base, Ethereum, Polygon, Arbitrum, Optimism — balances, gas prices, ENS, and a safelisted read-only RPC proxy, all built on free public nodes.
Safelisted read-only JSON-RPC proxy across five chains
eth_call, eth_getBalance, eth_blockNumber, and more
- method= eth_blockNumber(required)
- chain= base
- params= []
https://agentx402pay.com/api/rpc?method=eth_blockNumber&chain=base¶ms=%5B%5D
Native + optional ERC-20 token balance for any address
- address= 0xd8dA...6045(required)
- chain= base
- token= 0x8335...0913
https://agentx402pay.com/api/wallet-balance?address=0xd8dA...6045&chain=base&token=0x8335...0913
Current gas price + EIP-1559 fee estimate
- chain= base
https://agentx402pay.com/api/gas-price?chain=base
ENS name ⇄ address resolution
- name= vitalik.eth
https://agentx402pay.com/api/ens-resolve?name=vitalik.eth