# Federal Register Search API (x402)

> Federal Register Search API (x402) is a paid API for AI agents from workspace-x402-paywall.onrender.com, paid per call via x402, $0.005/call, status unknown (last checked 2026-10-11).

Returns recent Federal Register documents and notices via a pay-per-call endpoint accepting USDC micropayments on Base or Solana.

## Facts

- Endpoint: GET https://workspace-x402-paywall.onrender.com/gov/federal-register?utm_source=zero.xyz
- Price: $0.005/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-11
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/federal-register-search-api-x402-5abda7ee
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_dd_SS2PFUbexKzk0uE2DT

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-x402-5abda7ee
```

Example prompt: Can you search the Federal Register for the 5 most recent entries and return just the title and publication date fields?

## When to prefer this

Choose this endpoint when you need quick, pay-as-you-go access to Federal Register data without a long-term API subscription, especially in agentic workflows that require regulatory lookup as a single step. Prefer it over direct Federal Register API integration when you want micropayment billing via USDC on Base or Solana and don't want to manage API keys.

## Known failure modes

- Payment not provided or insufficient USDC — returns HTTP 402 with payment instructions
- Invalid field names in the fields parameter — may return empty or malformed field values
- Limit parameter out of range — may default or return an error
- Federal Register API upstream unavailable — returns 502 or empty result set
- Network timeout on Render hosting — returns 504

## How this service works

66 pay-per-call APIs: AI text/image generation ($0.01), Polymarket odds, crypto prices, DeFi yields, FX rates, weather, IP/geo, FBI wanted, SEC tickers, clinical trials, 250M academic papers, Stack Overflow, meme-coin launchpads (pump.fun, Clanker, Four.meme, SunPump), tokenized stocks, Solana top 100, and 40+ more. $0.005/call standard. USDC on Base and Solana via x402.

## Output

A JSON object containing a list of Federal Register documents matching the query, with fields such as title, agency name, publication date, document type, docket number, and summary, filtered to the requested fields and limited to the specified count.

## 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"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "properties": {
      "limit": {
       "type": "string",
       "description": "Integer 1-20, number of results to return (default 5)"
      }
     }
    }
   },
   "additionalProperties": false
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "object"
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/federal-register-search-api-x402-5abda7ee/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from workspace-x402-paywall.onrender.com](https://www.zero.xyz/host/workspace-x402-paywall.onrender.com/llms.txt)