WebExtract

Web page → clean Markdown + fixed-schema JSON, for AI agents. One GET request turns any public URL into LLM-ready Markdown plus structured data (article metadata, product/price, tables). Pay per call with x402 (USDC on Base, Polygon, Arbitrum, Avalanche, OP Mainnet, World Chain or Monad), buy prepaid credits with a card (Stripe), or use it from any MCP client.

• Website: https://webextract.dev
• API base: https://api.webextract.dev
• MCP (streamable HTTP): https://api.webextract.dev/mcp
• OpenAPI: https://api.webextract.dev/openapi.json · llms.txt: https://api.webextract.dev/llms.txt
• Docs: https://webextract.dev/docs
• Try a paid x402 call in your browser wallet: https://webextract.dev/try

Endpoints

Method	Path	Returns	x402 price	Credits
GET / POST	/v1/extract?url=<page>	Markdown + structured JSON (metadata, product/price, tables)	$0.005	1
GET / POST	/v1/markdown?url=<page>	Markdown only	$0.002	0.4
GET	/v1/balance	Free calls left today, or prepaid credits left	free	–
POST	/mcp	MCP tools extract_url, page_markdown	–	same as above
GET	/.well-known/x402	x402 discovery	free	–

POST takes the same URL as a JSON body: {"url": "https://..."}.

Behaviour:

• robots.txt is respected.
• No charge on failed fetches (404, timeout, blocked, robots disallowed, invalid URL).
• A missing or invalid url returns 400 JSON (missing_url / invalid_url) before any billing. All errors are JSON.
• Structured JSON costs nothing extra. With a prepaid key, if structured fields come back empty you're charged the Markdown rate (0.4 credit). x402 payments settle at the quoted price.

Pricing

• Free: 50 calls/day per IP, no key, no signup. REST: opt in with the header X-Billing: free (or ?free=1). MCP: no header needed.
• x402 pay-per-call: $0.005 (/v1/extract) / $0.002 (/v1/markdown) in USDC on any supported network (below). No account, no gas needed.
• Prepaid packs (card, via Stripe Checkout), from $1: $1 = 200 credits · $5 = 1,000 credits · $20 = 5,000 credits · $50 = 15,000 credits. /v1/extract uses 1 credit, /v1/markdown uses 0.4 credit. Credits never expire. Buy at https://webextract.dev/#pricing; the API key is shown once on the success page.

Quick start

# Free tier (opt-in: 50 calls/day per IP)
curl -H "X-Billing: free" "https://api.webextract.dev/v1/markdown?url=https://example.com"

# Prepaid key (Stripe)
curl -H "Authorization: Bearer $WEBEXTRACT_KEY" \
  "https://api.webextract.dev/v1/extract?url=https://example.com"

Response (abridged):

{
  "url": "https://example.com",
  "final_url": "https://example.com/",
  "title": "Example Domain",
  "markdown": "This domain is for use in documentation examples ...",
  "word_count": 25
}

Prepaid responses include X-Credits-Charged and X-Credits-Remaining headers; free-tier responses (only with X-Billing: free / ?free=1) include X-Free-Remaining. Without a key, a payment or X-Billing: free, the REST endpoints answer HTTP 402 (reason: x402_required).

Pay per call with x402

Requests without a key, payment or X-Billing: free get HTTP 402 (reason: x402_required; X-Billing: x402 gives the same 402 with reason: x402_requested) with an x402 v2 PAYMENT-REQUIRED header (scheme exact). It lists one option per network; pay with whichever one your wallet holds USDC on (see Choosing a network with the SDK):

Network	CAIP-2 id	USDC (native)	EIP-712 name / version
Base (recommended)	eip155:8453	0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913	USD Coin / 2
Polygon PoS	eip155:137	0x3c499c542cEF5E3811e1192ce70d8cC03d5c3359	USD Coin / 2
Arbitrum One	eip155:42161	0xaf88d065e77c8cC2239327C5EDb3A432268e5831	USD Coin / 2
Avalanche C-Chain	eip155:43114	0xB97EF9Ef8734C71904D8002F8b6Bc66Dd9c48a6E	USD Coin / 2
OP Mainnet	eip155:10	0x0b2C639c533813f4Aa9D7837CAf62653d097Ff85	USD Coin / 2
World Chain	eip155:480	0x79A02482A880bCE3F13e09Da970dC34db4CD24d1	USDC / 2
Monad	eip155:143	0x754704Bc059F8C67012fEd69BC8A327a5aafb603	USDC / 2

Not supported: USDC on Ethereum mainnet (no x402 facilitator settles there). Solana is planned.

The JSON body of every 402 says why, in reason (also in the X-Payment-Reason header):

reason	Meaning
x402_required	No key, no payment and no free opt-in. Pay with x402, use a key, or retry with X-Billing: free
x402_requested	You sent X-Billing: x402 and no payment yet
free_limit_reached	You opted in with X-Billing: free / ?free=1 but your IP's free calls are used up (X-Free-Remaining: 0)
invalid_payment	A payment was sent but rejected; detail has a short reason code (e.g. invalid_exact_evm_insufficient_balance). Not charged
unsupported_network	The payment used a network this endpoint does not accept
settlement_failed	The payment was verified but on-chain settlement did not complete. Not charged (retryable: true); retry with a freshly signed payment

An unknown X-Billing value returns 400 invalid_billing_mode. Precedence: a Bearer key wins over a payment, and a payment wins over X-Billing: free.

See the requirements without paying anything: examples/curl/x402-inspect.sh, examples/python/inspect_402.py or examples/node/inspect-402.mjs.

Choosing a network with the SDK

Any x402 client can pay and retry automatically. Two things to know with the official SDKs (@x402/fetch / @x402/evm 2.28, Python x402 2.25):

1. OP Mainnet and World Chain USDC are not in the SDK default asset list, so the default spendControls reject those options. Add them to spendControls.allowedAssets.
2. With network: "eip155:*" the SDK picks the first option (Base) even if your USDC is elsewhere. Register only the networks where your wallet holds USDC, or pass a paymentRequirementsSelector.

// npm i @x402/fetch @x402/evm viem
import { wrapFetchWithPaymentFromConfig } from "@x402/fetch";
import { ExactEvmScheme } from "@x402/evm";
import { privateKeyToAccount } from "viem/accounts";

const account = privateKeyToAccount(process.env.EVM_PRIVATE_KEY); // low-balance hot wallet
const funded = ["eip155:10"]; // networks where this wallet holds USDC, e.g. OP Mainnet
const fetchWithPayment = wrapFetchWithPaymentFromConfig(fetch, {
  schemes: funded.map(network => ({ network, client: new ExactEvmScheme(account) })),
  spendControls: { allowedAssets: [
    { network: "eip155:10",  asset: "0x0b2C639c533813f4Aa9D7837CAf62653d097Ff85", maxAmountPerPayment: "10000" }, // OP Mainnet USDC, $0.01 cap
    { network: "eip155:480", asset: "0x79A02482A880bCE3F13e09Da970dC34db4CD24d1", maxAmountPerPayment: "10000" }, // World Chain USDC
  ] },
});

const res = await fetchWithPayment(
  "https://api.webextract.dev/v1/extract?url=" + encodeURIComponent("https://example.com"),
  { headers: { "X-Billing": "x402" } }
);
console.log(await res.json());

examples/node/x402-fetch.mjs does this automatically: it reads your USDC balance on every supported network, registers only the funded ones, prefers Base, and has a --dry-run mode that signs nothing.

In a browser, https://webextract.dev/try shows your USDC balance on every supported network, lets you pick one, switches your wallet to it and signs the payment.

Payment is only settled when the request succeeds (status < 400).

Sandbox (free test money only)

Test your x402 integration without real money: call https://api.webextract.dev/sandbox/v1/extract or /sandbox/v1/markdown, or send X-Billing: x402-testnet to the normal endpoints. The sandbox accepts only Base Sepolia (eip155:84532) test USDC 0x036CbD53842c5426634e7929541eC2318f3dCF7e, settled by the https://x402.org/facilitator testnet facilitator. Get test USDC at https://faucet.circle.com. Responses are identical; nothing real is charged. Rate limited to 20 requests/minute and 300/day per IP.

WEBEXTRACT_BILLING=x402-testnet ./examples/curl/x402-inspect.sh markdown
WEBEXTRACT_SANDBOX=1 EVM_PRIVATE_KEY=0x<testnet-only key> node examples/node/x402-fetch.mjs

Use from MCP clients

Remote server, streamable HTTP, stateless: https://api.webextract.dev/mcp

Tools:

• extract_url(url): Markdown + structured JSON
• page_markdown(url): Markdown only (cheaper)

Works without a key on the free tier (50 calls/day per IP, no X-Billing header needed for MCP). For prepaid credits add header Authorization: Bearer <key>.

Both tools declare an outputSchema and return structuredContent. MCP calls use the free tier or a Bearer key; for pay-per-call without an account use the REST endpoints with x402.

Ready-made client configs in examples/mcp/:

Client	File
Cursor	cursor.mcp.json → ~/.cursor/mcp.json (with key: cursor.mcp.with-key.json, uses ${env:WEBEXTRACT_KEY})
VS Code	vscode.mcp.json → .vscode/mcp.json
Claude Desktop	claude_desktop_config.json (stdio bridge via npx mcp-remote; with key: claude_desktop_config.with-key.json). Or add the URL under Settings → Connectors.
Cline	cline_mcp_settings.json. Set "type": "streamableHttp" or Cline falls back to SSE and no tools appear. Step-by-step: llms-install.md.
Claude Code	claude-code.sh

Cursor-style config:

{
  "mcpServers": {
    "webextract": {
      "url": "https://api.webextract.dev/mcp",
      "headers": { "Authorization": "Bearer YOUR_KEY_OPTIONAL" }
    }
  }
}

Claude Code:

claude mcp add --transport http webextract https://api.webextract.dev/mcp

Listed in the official MCP Registry as dev.webextract/extract (see server.json).

Examples

• examples/curl/quickstart.sh: free tier or prepaid key, balance, Markdown and structured extract
• examples/curl/x402-inspect.sh: show and decode the x402 402 without paying
• examples/python/inspect_402.py: decode the 402 with the official Python x402 SDK (pip install -r examples/python/requirements.txt)
• examples/node/inspect-402.mjs: decode the 402 with @x402/core (cd examples/node && npm i)
• examples/node/x402-fetch.mjs: pay per call with x402 on the network where your wallet holds USDC (sandbox and dry-run modes)
• examples/mcp/: MCP client configs

Legal

Terms · Privacy · Refunds · Contact: duckbeijing518@gmail.com

License

This repository (docs, examples, metadata) is MIT licensed; see LICENSE. The hosted API is a commercial service.