# Open Source Filings – US Federal Court Case Search

> Open Source Filings – US Federal Court Case Search is a paid API for AI agents from api.osf-master-server.com, paid per call via x402, $0.05/call, status down (last checked 2026-09-15).

Search 1.55 million+ US federal court opinions and SEC enforcement actions by case name, party, court, or citation, returning structured case metadata and provenance URLs.

## Facts

- Endpoint: GET https://api.osf-master-server.com/x402/legal/cases/:query
- Price: $0.05/call
- Payment: x402
- Status: down
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/open-source-filings-us-federal-court-case-search-40100be8
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_ggiFtO0eEkfGCBqH9lqCA

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 open-source-filings-us-federal-court-case-search-40100be8
```

Example prompt: Can you look up federal court cases about qualified immunity in the Ninth Circuit — I need the case names, courts, dates, and citation info?

## When to prefer this

Use this endpoint when you need to identify, verify, or retrieve metadata for US federal court cases or SEC enforcement actions by name, party, topic, or citation. Best for legal research, compliance checks, and citation lookups across SCOTUS and all 13 federal appellate circuits plus SEC proceedings. Not suitable for full opinion text retrieval, state court cases, or non-US jurisdictions.

## Known failure modes

- Query too vague returns too many or irrelevant matches
- Obscure or misspelled case names may return no results
- State court cases are not covered — only federal appellate and SCOTUS plus SEC actions
- Full opinion text is not returned, only metadata and citations
- Payment failure (402) if USDC balance is insufficient

## How this service works

Look up US federal court cases by case name, party, court, or citation across 1.55 million+ opinion records: SCOTUS all time and all 13 federal appellate circuits (CourtListener), plus SEC litigation releases and SEC administrative proceedings. Returns case name, court, date, citations and a provenance URL per match. Case metadata and citations, not opinion full text.

## Output

A list of matching case records, each containing the case name, court, decision date, legal citations, and a provenance URL linking to the source record on CourtListener or the SEC website. Does not include full opinion text.

## 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"
    },
    "pathParams": {
     "type": "object",
     "required": [
      "query"
     ],
     "properties": {
      "query": {
       "type": "string",
       "description": "Keyword(s): case name, party, topic, citation, or court. E.g. 'miranda arizona' or 'ninth circuit qualified immunity'."
      }
     }
    },
    "queryParams": {
     "type": "object",
     "properties": {}
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/open-source-filings-us-federal-court-case-search-40100be8/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.osf-master-server.com](https://www.zero.xyz/host/api.osf-master-server.com/llms.txt)