# Federal Register Search API (x402)

> Federal Register Search API (x402) is a paid API for AI agents from x402-data-api-x6da.onrender.com, paid per call via x402, $0.02/call, status unknown (last checked 2026-10-30).

Search and retrieve federal government documents from the Federal Register, including rules, proposed rules, notices, and presidential documents, filtered by agency, keyword, and date range.

## Facts

- Endpoint: GET https://x402-data-api-x6da.onrender.com/v1/gov/federal-register?utm_source=zero.xyz
- Price: $0.02/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-30
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/federal-register-search-api-x402-28d0b260
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_9_XDyaOMQJhIwndf6Tiba

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 federal-register-search-api-x402-28d0b260
```

Example prompt: Search the Federal Register for proposed rules from the environmental-protection-agency about clean air standards published between January 1 2024 and June 30 2024, and return up to 10 results.

## When to prefer this

Use this endpoint when you need to search official U.S. federal regulatory documents from the Federal Register by keyword, agency, document type, or date range. It is ideal for compliance monitoring, regulatory research, and policy tracking workflows where authoritative government source data is required. Prefer this over web search when you need structured, filterable access to federal rulemaking and notices.

## Known failure modes

- No results returned if query terms do not match any documents in the date range
- Invalid agency slug returns an error or empty result set
- Unsupported document type enum value returns a validation error
- Date format errors if date_from or date_to are not properly formatted
- Payment failure if USDC balance is insufficient for x402 micropayment

## How this service works

Jobs from company ATS boards, SEC EDGAR full-text search, domain RDAP/DNS, NHTSA VIN decode + recalls, the CMS NPI Registry and MET Norway weather forecasts. Pay per call in USDC on Solana via x402. Official public sources only.

## Output

Returns a list of matching Federal Register documents including metadata such as document type (RULE, PRORULE, NOTICE, PRESDOCU), publishing agency, title, date, abstract, and links to the full text on federalregister.gov.

## 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"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET",
      "HEAD",
      "DELETE"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "properties": {
      "q": {
       "type": "string"
      },
      "type": {
       "enum": [
        "RULE",
        "PRORULE",
        "NOTICE",
        "PRESDOCU"
       ],
       "type": "string"
      },
      "agency": {
       "type": "string",
       "description": "agency slug, e.g. environmental-protection-agency"
      },
      "date_to": {
       "type": "string"
      },
      "date_from": {
       "type": "string"
      },
      "max_results": {
       "type": "integer"
      }
     }
    }
   },
   "additionalProperties": false
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/federal-register-search-api-x402-28d0b260/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from x402-data-api-x6da.onrender.com](https://www.zero.xyz/host/x402-data-api-x6da.onrender.com/llms.txt)