# 2s RFC Lookup

> 2s RFC Lookup is a paid API for AI agents from 2s.io, paid per call via x402, $0.0012/call, status unknown (last checked 2026-09-16).

Look up metadata for any IETF RFC document by number, returning title, status, authors, dates, and obsolescence relationships

## Facts

- Endpoint: GET https://2s.io/api/dev/rfc
- Price: $0.0012/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-16
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/2s-rfc-lookup-691c737e
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_Yci1RgXAxwacDY-d8R_NP

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability 2s-rfc-lookup-691c737e
```

Example prompt: Can you look up RFC 2616 for me — I want to know its title, who wrote it, when it was published, its current status, and whether it's been obsoleted by anything?

## When to prefer this

Use this endpoint when you need structured metadata about a specific RFC document — especially status, authorship, and obsolescence chain — without scraping the IETF website. Ideal for agents verifying whether a protocol standard is current or determining which RFCs supersede a given one.

## Known failure modes

- RFC number not found — returns empty or null rfc object
- Invalid RFC number format — query parameter must be a string like '2616' or 'RFC2616'
- Payment failure via x402 — 402 response if USDC payment not provided
- Network timeout for bundled dataset lookup

## How this service works

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 Use this to resolve whether a spec is current or superseded before relying on it.

## Output

Returns a JSON object with the RFC's number, title, publication date, status (e.g. DRAFT STANDARD, HISTORIC), IETF stream, list of authors, DOI, canonical URL, and arrays of RFC numbers it obsoletes, is obsoleted by, updates, and is updated by.

## Example request

```json
{
 "input": {
  "type": "http",
  "method": "GET",
  "queryParams": {
   "number": "2616"
  }
 }
}
```

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method",
    "queryParams"
   ],
   "properties": {
    "type": {
     "const": "http"
    },
    "method": {
     "const": "GET"
    },
    "queryParams": {
     "required": [
      "number"
     ],
     "properties": {
      "number": {
       "type": "string",
       "description": "RFC number, e.g. RFC2616, 2616."
      }
     }
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/2s-rfc-lookup-691c737e/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from 2s.io](https://www.zero.xyz/host/2s.io/llms.txt)