CourtListener API Guide

Overview

CourtListener is a free legal research platform operated by Free Law Project, a non-profit organization dedicated to making legal data freely accessible. The platform hosts one of the largest open collections of U.S. case law, containing millions of court opinions, docket entries, oral arguments, and judge profiles sourced from PACER (Public Access to Court Electronic Records), state court websites, and historical digitization efforts.

The CourtListener REST API provides programmatic access to this extensive legal database, enabling searches across court opinions, dockets, judge biographical data, and court information. The API covers federal courts (Supreme Court, Circuit Courts, District Courts, Bankruptcy Courts) and many state courts, with records spanning from the founding of the republic to the present day.

Legal scholars, law students, practicing attorneys, journalists, policy researchers, and civic technologists use the CourtListener API to conduct legal research, perform empirical legal studies, build litigation analytics tools, track judicial behavior, monitor active litigation, and analyze trends in case law. It serves as a critical resource for computational legal studies and access-to-justice initiatives.

Authentication

No authentication is required for basic API access. The CourtListener API is publicly accessible for read operations. However, creating an account and using an API token provides higher rate limits and access to additional features. Authentication is recommended for production applications.

To obtain an API token:

1. Create a free account at https://www.courtlistener.com/
2. Navigate to your profile settings
3. Generate an API token
4. Include it in the

   Authorization

   header

# Unauthenticated request
curl "https://www.courtlistener.com/api/rest/v4/opinions/?q=first+amendment"

# Authenticated request (higher rate limits)
curl -H "Authorization: Token YOUR_TOKEN" \
  "https://www.courtlistener.com/api/rest/v4/opinions/?q=first+amendment"

Core Endpoints

opinions: Search Court Opinions

Search and retrieve the full text of court opinions (judicial decisions) across all indexed courts.

• URL:

  GET https://www.courtlistener.com/api/rest/v4/opinions/

• Parameters:

scotus

ca9

010combined

020lead

date_filed

-date_filed

• Example:

curl "https://www.courtlistener.com/api/rest/v4/opinions/?q=privacy+fourth+amendment&court=scotus&ordering=-date_filed"

• Response: Returns paginated results with

  count

  ,

  next

  ,

  previous

  , and

  results

  array. Each opinion includes

  id

  ,

  absolute_url

  ,

  cluster

  (case metadata),

  author

  (judge),

  type

  ,

  date_filed

  ,

  plain_text

  or

  html

  (opinion text),

  download_url

  , and

  citations

  .

dockets: Access Case Dockets

Search and retrieve docket information including case metadata, parties, attorneys, and docket entries from PACER and other sources.

• URL:

  GET https://www.courtlistener.com/api/rest/v4/dockets/

• Parameters:

• Example:

curl "https://www.courtlistener.com/api/rest/v4/dockets/?q=antitrust&court=scotus&ordering=-date_filed"

• Response: Returns

  count

  ,

  results

  array with

  id

  ,

  case_name

  ,

  docket_number

  ,

  court

  ,

  date_filed

  ,

  date_terminated

  ,

  nature_of_suit

  ,

  assigned_to

  (judge),

  referred_to

  , and

  docket_entries

  .

courts: Court Information

Retrieve information about courts in the CourtListener database, including jurisdiction, location, and identifiers.

• URL:

  GET https://www.courtlistener.com/api/rest/v4/courts/

• Parameters:

F

S

• Example:

curl "https://www.courtlistener.com/api/rest/v4/courts/?jurisdiction=F"

• Response: Returns court objects with

  id

  ,

  full_name

  ,

  short_name

  ,

  jurisdiction

  ,

  position

  ,

  start_date

  ,

  end_date

  , and

  url

  .

people: Judge Profiles

Access biographical and professional information about judges, including their appointment history, education, and political affiliations.

• URL:

  GET https://www.courtlistener.com/api/rest/v4/people/

• Parameters:

• Example:

curl "https://www.courtlistener.com/api/rest/v4/people/?q=ginsburg"

• Response: Returns judge profiles with

  id

  ,

  name_first

  ,

  name_last

  ,

  date_of_birth

  ,

  gender

  ,

  positions

  (court appointments with dates),

  education

  ,

  political_affiliations

  , and

  aba_ratings

  .

search: Unified Search

Perform a unified full-text search across all CourtListener content types.

• URL:

  GET https://www.courtlistener.com/api/rest/v4/search/

• Parameters:

o

r

oa

• Example:

curl "https://www.courtlistener.com/api/rest/v4/search/?q=net+neutrality&type=o"

• Response: Returns unified search results with relevance scoring across content types.

Rate Limits

The CourtListener API allows up to 5,000 requests per hour for unauthenticated users. Authenticated users with API tokens receive higher limits. The API returns standard HTTP 429 responses when limits are exceeded. For bulk data access, CourtListener provides downloadable bulk data files at https://www.courtlistener.com/api/bulk-info/ which are more appropriate for large-scale research projects. The bulk data includes complete opinion texts, docket metadata, and judge biographical data.

Common Patterns

Track Recent Supreme Court Opinions

Monitor new opinions from the Supreme Court of the United States:

import requests

params = {
    "court": "scotus",
    "ordering": "-date_filed",
    "page_size": 10
}
resp = requests.get("https://www.courtlistener.com/api/rest/v4/opinions/", params=params)
data = resp.json()

for opinion in data["results"]:
    cluster = opinion.get("cluster", {})
    print(f"{opinion['date_filed']}: {cluster.get('case_name', 'Unknown')}")

Empirical Analysis of Judicial Citations

Study citation patterns across courts and time periods:

import requests

params = {
    "q": "stare decisis",
    "court": "scotus",
    "date_filed_min": "2020-01-01",
    "ordering": "-date_filed"
}
resp = requests.get("https://www.courtlistener.com/api/rest/v4/search/", params={**params, "type": "o"})
results = resp.json()

print(f"Found {results['count']} opinions mentioning 'stare decisis' since 2020")

Judge Appointment Analysis

Research judicial appointments and their characteristics:

curl "https://www.courtlistener.com/api/rest/v4/people/?court=scotus&ordering=-date_nominated"

References

• Official API documentation: https://www.courtlistener.com/api/rest-info/
• CourtListener homepage: https://www.courtlistener.com/
• Bulk data downloads: https://www.courtlistener.com/api/bulk-info/
• Free Law Project: https://free.law/
• RECAP Archive: https://www.courtlistener.com/recap/