Look up an IETF RFC by number. Pass number as RFC2616, 2616, or the integer 2616. Returns the RFC title, authors, publication date, status (e.g. INTERNET STANDARD, PROPOSED STANDARD, DRAFT STANDARD, INFORMATIONAL, EXPERIMENTAL, HISTORIC, BEST CURRENT PRACTICE), stream (IETF/IAB/IRTF/Independent/Legacy), DOI, canonical rfc-editor.org URL, and the full standards relationship chain: which RFCs this one obsoletes / is obsoleted by, and which it updates / is updated by. Authoritative data from the IETF/RFC Editor index. Use this to resolve whether a spec is current or superseded before relying on it.
/api/dev/rfcPAYMENT-SIGNATURE.The rfc API is a pay-per-call dev endpoint built for AI agents and autonomous software. Look up an IETF RFC by number.
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 rfc data source for an agent tool-use loop, an MCP host, or a backend that needs dev data on demand without onboarding to yet another vendor portal.
| Name | Type | Description |
|---|---|---|
numberrequired | string | RFC number, e.g. RFC2616 or 2616. min 1 chars · max 12 chars |
# 1. Probe with no auth → 402 envelope with PaymentRequirements curl -sS 'https://2s.io/api/dev/rfc?number=example' # 2. Sign + retry with PAYMENT-SIGNATURE: curl -sS 'https://2s.io/api/dev/rfc?number=example' \ -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/dev/rfc?number=example'
import { TwoS } from '@2sio/sdk'
const client = new TwoS({
privateKey: process.env.EVM_PRIVATE_KEY as `0x${string}`,
})
const result = await client.dev.rfc({
"number": "example"
})
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.dev.rfc(number="example")
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": "dev.rfc",
"arguments": {
"number": "example"
}
}
}| Field | Type | Description |
|---|---|---|
query | object | |
returned | number | |
rfc | object | |
source | object |
{
"query": {
"number": 1
},
"returned": 1,
"rfc": {
"number": 1,
"title": "example",
"authors": [
"example"
],
"date": "example",
"status": "example",
"stream": "example",
"obsoletes": [
1
],
"obsoletedBy": [
1
],
"updates": [
1
],
"updatedBy": [
1
],
"doi": "example",
"url": "example"
},
"source": {
"provider": "example",
"url": "example",
"license": "example"
}
}