Search US case law / court opinions (CourtListener) API

Full-text search across millions of US court opinions via CourtListener (Free Law Project), normalized with citations, court, filing date, BM25 relevance, and a derived distinct-court spread + most-cited hit. Answers 'What opinions discuss qualified immunity?', 'Which case on this issue is most cited?'.

Price$0.01per request

MethodPOST

Route/v1/gov/courtlistener-opinion-search

StatusLive

MIME typeapplication/json

Rate limit60/minute

Cache3600s public

govlegalcourtscase-lawopinionscourtlistenersearchus

API URLhttps://x402.hexl.dev/v1/gov/courtlistener-opinion-search

Integration docs

Example request

{
  "query": "qualified immunity",
  "limit": 3
}

Example response

{
  "query": "qualified immunity",
  "totalMatches": 99086,
  "returned": 3,
  "distinctCourts": 2,
  "mostCitedCase": {
    "caseName": "Kim v. Randal Lowry & Assocs.",
    "citeCount": 5,
    "url": "https://www.courtlistener.com/opinion/4847328/kim-v-randal-lowry-assocs/"
  },
  "opinions": [
    {
      "caseName": "Statutes Severability – Lead Poisoning Prevention – \"Qualified Offer\" Provisions of Reduction of Lead Risk in Housing Act are Not Severable from the Immunity Provisions Invalidated in Jackson v. Dackman",
      "court": "Maryland Attorney General Reports",
      "courtId": "mdag",
      "citation": null,
      "dateFiled": "2017-12-06",
      "docketNumber": "102 OAG 16",
      "judge": null,
      "citeCount": 0,
      "clusterId": 4448997,
      "relevanceScore": 64.01,
      "url": "https://www.courtlistener.com/opinion/4448997/statutes-severability-lead-poisoning-prevention-qualified-offer/"
    },
    {
      "caseName": "Kim v. Randal Lowry & Assocs.",
      "court": "Ohio Court of Appeals",
      "courtId": "ohioctapp",
      "citation": [
        "166 N.E.3d 146",
        "2021 Ohio 51"
      ],
      "dateFiled": "2021-01-13",
      "docketNumber": "29680",
      "judge": "Schafer",
      "citeCount": 5,
      "clusterId": 4847328,
      "relevanceScore": 51,
      "url": "https://www.courtlistener.com/opinion/4847328/kim-v-randal-lowry-assocs/"
    }
  ],
  "disclaimer": "Informational data product aggregated from public government / open-legal APIs. NOT legal advice. Verify against the official primary source before relying on it."
}

Input schema

{
  "type": "object",
  "required": [
    "query"
  ],
  "properties": {
    "query": {
      "type": "string",
      "description": "Legal search phrase"
    },
    "court": {
      "type": "string",
      "description": "Optional court id filter, e.g. 'scotus','ca9'"
    },
    "limit": {
      "type": "integer",
      "minimum": 1,
      "maximum": 25,
      "default": 10
    }
  }
}

Output schema

{
  "type": "object",
  "additionalProperties": true
}