Search the US Federal Register — proposed rules, final rules, notices, and presidential documents. Filter by free-text term, document type (RULE/PRORULE/NOTICE/PRESDOCU), agency slug (e.g., epa, fda, sec), and publication date range. Returns document_number, type, title, abstract, FR citation, agencies, publication_date, effective_on, comments_close_on, htmlUrl, pdfUrl, rawTextUrl. Public-domain US government data. Real-time — published daily, past LLM training cutoff.
/api/law/federal-registerPAYMENT-SIGNATURE.The federal register API is a pay-per-call law endpoint built for AI agents and autonomous software. Search the US Federal Register — proposed rules, final rules, notices, and presidential documents.
There is no signup and no API key. An agent (or any HTTP client) hits the endpoint, receives an x402 "402 Payment Required" challenge, signs a sub-cent USDC payment on Base or Solana, and retries — the data comes back on the paid request. That makes it a drop-in federal register data source for an agent tool-use loop, an MCP host, or a backend that needs law data on demand without onboarding to yet another vendor portal.
| Name | Type | Description |
|---|---|---|
qrequired | string | min 1 chars · max 500 chars |
type | string | one of: RULE | PRORULE | NOTICE | PRESDOCU |
agency | string | match ^[a-z0-9-]{2,60}$ |
since | string | match ^\d{4}-\d{2}-\d{2}$ |
until | string | match ^\d{4}-\d{2}-\d{2}$ |
limit | integer | min 1 · max 20 |
# 1. Probe with no auth → 402 envelope with PaymentRequirements curl -sS 'https://2s.io/api/law/federal-register?q=example&type=RULE&agency=example&since=2024-01-01&until=2024-01-01&limit=10' # 2. Sign + retry with PAYMENT-SIGNATURE: curl -sS 'https://2s.io/api/law/federal-register?q=example&type=RULE&agency=example&since=2024-01-01&until=2024-01-01&limit=10' \ -H 'PAYMENT-SIGNATURE: <base64-json-payload>' # Or use the canonical runner (handles probe → sign → retry): # EVM_PRIVATE_KEY=0x... node --env-file=.env.local \ # --experimental-strip-types scripts/x402-pay.ts \ # 'https://2s.io/api/law/federal-register?q=example&type=RULE&agency=example&since=2024-01-01&until=2024-01-01&limit=10'
import { TwoS } from '@2sio/sdk'
const client = new TwoS({
privateKey: process.env.EVM_PRIVATE_KEY as `0x${string}`,
})
const result = await client.law.federalRegister({
"q": "example",
"type": "RULE",
"agency": "example",
"since": "2024-01-01",
"until": "2024-01-01",
"limit": 10
})
console.log('endpoint:', result.endpoint)
console.log('cost:', result.costUsd, 'USDC')
console.log('tx:', result.settlement?.txHash)
console.log('data:', result.data)import os
from twosio import TwoS
client = TwoS(private_key=os.environ["EVM_PRIVATE_KEY"])
result = client.law.federal_register(q="example", type="RULE", agency="example", since="2024-01-01", until="2024-01-01", limit=10)
print("endpoint:", result.endpoint)
print("cost:", result.cost_usd, "USDC")
print("tx:", (result.settlement or {}).get("tx_hash"))
print("data:", result.data)// 1. Add @2sio/mcp to your MCP host config (Claude Desktop example below).
// EVM_PRIVATE_KEY funds x402 payments per call.
// claude_desktop_config.json
{
"mcpServers": {
"2sio": {
"command": "npx",
"args": ["-y", "@2sio/mcp"],
"env": { "EVM_PRIVATE_KEY": "0x..." }
}
}
}
// 2. Once the server is running, agents call this tool via standard MCP:
{
"jsonrpc": "2.0",
"id": 1,
"method": "tools/call",
"params": {
"name": "law.federal-register",
"arguments": {
"q": "example",
"type": "RULE",
"agency": "example",
"since": "2024-01-01",
"until": "2024-01-01",
"limit": 10
}
}
}| Field | Type | Description |
|---|---|---|
ok | boolean | one of: true |
items | array | |
total | integer | Total matching rows upstream; null when unknown. |
source | object | |
meta | object |
{
"ok": true,
"items": [
{}
],
"total": 1,
"source": {
"provider": "example",
"url": "example",
"license": "example"
},
"meta": {
"query": {
"term": "example",
"type": "example",
"agency": "example",
"since": "example",
"until": "example",
"limit": 1
}
}
}