law.federal-register

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.

price

$0.0010 USDC per call

method

GET/api/law/federal-register

payment

x402 v2 · EIP-3009 transferWithAuthorization · USDC on Base mainnet

auth

None. Sign the payment, retry with PAYMENT-SIGNATURE.

tier

Tier 0 — no paid upstream

Parameters

Name	Type	Description
`q`required	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

Code samples

cURLbash

# 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'

TypeScript / Node — @2sio/sdktypescript

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)

Python — 2siopython

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)

MCP — Claude Desktop / AgentKit / any MCP hostjson

// 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
    }
  }
}

Discovery

/api/directory — full catalog of every endpoint
/openapi.json — OpenAPI 3.1 spec (per-op x-payment-info, x402Payment security)
/.well-known/x402 — machine-readable service descriptor for x402-aware crawlers
/.well-known/mcp/server-card.json — MCP SEP-1649 server card
/llms.txt — plain-text manifest for LLM ingestion

2s.io is x402-native. Every call is paid per-request from a USDC-funded EVM wallet on Base — no signup, no API keys, no monthly fees. Source code: github.com/2s-io/sdk.