PACER API: Federal Court Data Access Guide

Direct answer: The official PACER API ecosystem—maintained by the Administrative Office of the U.S. Courts—consists of two primary services: the PACER Authentication API (CSO Auth) and the PACER Case Locator (PCL) REST API. Automated research pipelines send a POST request with valid credentials to obtain an authentication token, which is then passed in HTTP headers to query nationwide federal court cases and party records in JSON or XML.

What It Is Used for in Research

Public Access to Court Electronic Records (PACER) provides electronic access to case and docket information from U.S. federal appellate, district, and bankruptcy courts. For scholars conducting quantitative legal analysis—such as studies published in the Journal of Empirical Legal Studies or foundational investigations into what legal studies entails—manual browser downloads are inefficient for large-scale data collection.

The PACER APIs allow researchers to programmatically ingest case filings, track litigation patterns across federal jurisdictions, extract judge assignment metadata, and assess judicial decision-making without manual scraping. Furthermore, transparent methodology in empirical legal research supports reproducibility; documenting automated docket collection pipelines aligns with standard data availability statements in published empirical literature.

Install or Access (Official Source Only)

Access to official PACER APIs is managed directly by the Administrative Office of the U.S. Courts through the PACER Service Center. There is no public PyPI package or third-party client maintained by the federal Judiciary; researchers interact directly with the REST endpoints via standard HTTP client libraries (such as Python’s requests or httpx, or curl).

To establish API access:

1. Register an Account: Create a standard PACER account via pacer.uscourts.gov. Commercial or academic accounts require a valid credit card on file for billing.
2. Register for the QA Environment: The Administrative Office maintains a dedicated non-billable Quality Assurance (QA) testing environment at qa-pacer.uscourts.gov and qa-login.uscourts.gov. Researchers should test automated scripts in the QA environment using dummy records before running live queries against production.
3. Configure Multi-Factor Authentication: If Time-Based One-Time Passcode (TOTP) MFA is enabled on the account, scripts must generate a dynamic 6-digit TOTP token using a shared secret during programmatic login.

Step-by-Step Task: Authenticating and Querying Case Records

Programmatic access requires two consecutive steps: retrieving a session token and querying the Case Locator.

Step 1: Obtain an Authentication Token (CSO Auth)

Send an HTTP POST request to the authentication endpoint:

• Production URL: https://pacer.login.uscourts.gov/services/cso-auth
• QA Testing URL: https://qa-login.uscourts.gov/services/cso-auth
• Headers: Content-Type: application/json, Accept: application/json

POST /services/cso-auth HTTP/1.1
Host: pacer.login.uscourts.gov
Content-Type: application/json
Accept: application/json

{
  "loginId": "YOUR_PACER_USERNAME",
  "password": "YOUR_PACER_PASSWORD",
  "clientCode": "RESEARCH_PROJECT_01"
}

A successful request returns HTTP 200 containing a security token (such as a PacerSession value) and the billing status of the account.

Step 2: Query the PACER Case Locator (PCL) API

With the authentication token in hand, submit a search query to the PCL REST endpoint. Queries can filter by court type, jurisdiction, case number, filing date range, or party name.

GET /pcl-api/rest/cases/find?caseTitle=Acme&courtId=candce HTTP/1.1
Host: pacer.login.uscourts.gov
X-Pacer-Session: YOUR_SESSION_TOKEN
Accept: application/json

The Administrative Office requests that researchers executing bulk data queries schedule automated batch requests between 6:00 p.m. and 6:00 a.m. Central Time to minimize system degradation for active litigants.

Output and How to Read It

The PCL API returns structured JSON or XML conforming to the official federal court schema definitions (including pcl-api-cases.xsd and pcl-api-parties.xsd).

A standard case search response contains:

• caseId: The internal court identifier for the docket.
• caseNumber: The official docket number (e.g., 3:24-cv-01234).
• courtId: The court code (e.g., candce for U.S. District Court for the Northern District of California).
• dateFiled: The formal case opening date.
• caseTitle: Short caption identifying the adverse parties.
• caseStatus: Open, closed, or pending appeal.

Researchers should note that the PCL API provides nationwide index and case-level metadata; retrieving docket sheets or underlying filed PDF documents requires separate requests to the individual court’s CM/ECF system.

Troubleshooting Common Errors

• HTTP 401 Unauthorized: Credentials invalid, password expired, or missing TOTP token if MFA is enabled. Re-authenticate via /services/cso-auth.
• HTTP 403 Forbidden: Account suspended, credit card billing limit reached, or IP temporarily throttled due to excessive request volume outside scheduled batch hours.
• HTTP 500 / 503 Maintenance: PACER undergoes regular weekend system maintenance windows (typically Sundays); check official notices on pacer.uscourts.gov.
• Session Expiration: Authentication tokens expire after a defined period of inactivity. Scripts must monitor HTTP response headers and re-authenticate when a 401 response code is returned.

Free Alternatives (Table)

Because official PACER searches incur per-page fees ($0.10 per page, up to a $3.00 cap per document), researchers often utilize open-access repositories and secondary aggregators for preliminary corpus building.

Platform / Repository	Coverage	API Access	Cost Model
CourtListener (Free Law Project)	Millions of federal dockets and opinions via RECAP archive	Public REST API with webhook alerts	Free / Open source
Caselaw Access Project (CAP)	Historical official state and federal case law (Harvard Law School)	Bulk downloads and public API endpoints	Free public domain
Google Scholar Legal	Federal and state appellate court opinions	No public REST API (web interface only)	Free search
Justia	Federal district court dockets and opinions	Commercial syndication feeds	Free web access

Frequently Asked Questions

Does the PACER API charge fees for searching?

Yes. Programmatic searches conducted via the production PCL API are billed under the standard Judicial Conference fee schedule ($0.10 per search or page, up to $3.00 per document). Fees are waived for users who accrue less than $30 in a quarterly billing cycle. The QA testing environment is free of charge.

Can I download document PDFs directly through the PCL API?

No. The PCL API searches the national case index and returns docket metadata. Downloading actual filed document PDFs requires connecting to the specific court’s CM/ECF system or utilizing open archives such as the Free Law Project RECAP repository.

What are the permitted scraping hours for large bulk data pulls?

The Administrative Office requests that large automated data pulls be conducted between 6:00 p.m. and 6:00 a.m. Central Time to avoid impacting court staff and active litigants during standard court business hours.

How do empirical researchers share data collected via PACER?

Because federal court records are public domain government works, empirical researchers frequently archive cleaned tabular datasets in persistent repositories or preprint archives—such as discussed when comparing arXiv versus SSRN—and reference them in publication under standardized law review authorship norms.

Sources

• Administrative Office of the U.S. Courts. “PACER Developer Resources.” Available at: https://pacer.uscourts.gov/file-case/developer-resources (Accessed 2026-11-07).
• Administrative Office of the U.S. Courts. “PACER Case Locator (PCL) API User Guide.” Available at: https://pacer.uscourts.gov/help/pacer/pacer-case-locator-pcl-api-user-guide (Accessed 2026-11-07).
• Administrative Office of the U.S. Courts. “PACER Authentication API User Guide.” Available at: https://pacer.uscourts.gov/help/pacer/pacer-authentication-api-user-guide (Accessed 2026-11-07).