# CourtListener Federal Court Opinion Search

> CourtListener Federal Court Opinion Search is a paid API for AI agents from legal.memoryapi.org, paid per call via x402, $0.01/call, status down (last checked 2026-09-15).

Search federal court opinions and cases from the CourtListener/RECAP Archive by keyword, party, court, or date range.

## Facts

- Endpoint: GET https://legal.memoryapi.org/x402/legal/search
- Price: $0.01/call
- Payment: x402
- Status: down
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/legal-memoryapi-org-f2346f81
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_RSETcVqRiWeEHsHcJIKWb

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 legal-memoryapi-org-f2346f81
```

Example prompt: Search federal court opinions for cases about 'patent infringement' involving Apple, filed after 2020 in the Ninth Circuit — pull back the top results with case names, docket numbers, and filing dates.

## When to prefer this

Use this endpoint when you need to search across the full corpus of federal court opinions and dockets from CourtListener/RECAP — ideal for legal research, company litigation due diligence, case law retrieval by topic, or finding cases by party name. Prefer this over general web search when you need structured case metadata (docket numbers, courts, dates) rather than narrative summaries.

## Known failure modes

- No results found for overly narrow or obscure queries — returns empty result set
- Rate limiting or payment failure (x402) — returns 402 Payment Required
- Malformed query parameters — returns 400 Bad Request
- CourtListener upstream unavailable — returns 503 or timeout
- Query too broad returns truncated or paginated results with no clear cutoff signal

## How this service works

Federal court opinion search via CourtListener. Search 10M+ opinions, docket records, and case history. Pay-per-request via x402 protocol on Base mainnet.

## Output

Returns a list of matching federal court opinions and cases from the CourtListener/RECAP Archive, including case names, docket numbers, court identifiers, filing dates, judges, and relevant citation information for each result.

## Example request

```json
{
 "q": "patent infringement",
 "court": "ca9",
 "limit": 10,
 "date_after": "2020-01-01"
}
```

## Request schema (JSON Schema)

```json
{
 "properties": {
  "input": {
   "required": [
    "method"
   ],
   "properties": {
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "example": {
  "count": 10,
  "query": "Apple antitrust",
  "source": "CourtListener / RECAP Archive",
  "results": [
   {
    "url": "https://www.courtlistener.com/opinion/...",
    "court": "ca9",
    "snippet": "...antitrust...",
    "citation": "67 F.4th 946",
    "case_name": "Epic Games v. Apple Inc.",
    "date_filed": "2021-09-10",
    "docket_number": "21-16695"
   }
  ],
  "success": true,
  "total_available": 342
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/legal-memoryapi-org-f2346f81/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from legal.memoryapi.org](https://www.zero.xyz/host/legal.memoryapi.org/llms.txt)