Federal case numbers encode the court, year, case type, and sequence number in a compact string. The format is consistent enough to parse programmatically, but has edge cases by court type and jurisdiction that matter when building automated systems. This reference covers the standard format, all case type codes, variations across court types, and how to use case IDs with DocketLayer.

Standard format

1:24-cv-01234
1
Division
24
Year filed
cv
Case type
01234
Sequence number

The four components are separated by colons and hyphens as shown. The division prefix is separated by a colon; the remaining three parts are separated by hyphens.

Division identifies which divisional office within the district received the case. Most districts use 1 as the default. Some large districts with multiple courthouses — like the Central District of California — assign division numbers corresponding to their courthouse locations (1 for Los Angeles, 2 for Riverside, 5 for Santa Ana, and so on).

Year is always two digits: the last two digits of the calendar year in which the case was filed. A case filed in 2024 shows as 24; one filed in 2019 shows as 19.

Case type is a two-to-four letter code. See the full list below.

Sequence number is a zero-padded integer assigned by the clerk's office. Padding is typically five digits but varies by court and volume.

Case type codes

Code Type Notes
cv Civil The most common type in district courts. Covers commercial disputes, employment, civil rights, IP, and most federal litigation.
cr Criminal Federal criminal prosecutions. Filed by the US government against defendants.
bk Bankruptcy Used in bankruptcy courts. The primary type for Chapter 7, 11, and 13 cases.
ap Adversary proceeding A lawsuit filed within a bankruptcy case. Appears in bankruptcy court alongside the main bk case.
mc Miscellaneous Used for matters that do not fit other categories — subpoena enforcement, foreign proceedings, grand jury matters.
po Petty offense Minor criminal matters such as traffic violations on federal property.
mj Magistrate judge Cases assigned directly to a magistrate judge, typically minor civil or criminal matters.

Examples by court type

District court — civil:
1:24-cv-01234
Southern District of New York, civil, filed 2024

District court — criminal:
1:23-cr-00456
Southern District of New York, criminal, filed 2023

Bankruptcy court — main case:
1:22-bk-11068
District of Delaware bankruptcy, Chapter 11, filed 2022

Bankruptcy court — adversary proceeding:
1:22-ap-50123
Adversary proceeding within bankruptcy case

Multi-division district — California Central:
2:24-cv-08765
CACD, division 2 (Riverside), civil, filed 2024

Miscellaneous:
1:24-mc-00089
Miscellaneous matter, filed 2024

Edge cases and variations

No division prefix. Some courts omit the division prefix entirely, using a format like 24-cv-01234 instead of 1:24-cv-01234. This is less common but appears in some smaller single-division districts. DocketLayer normalizes these to the standard format internally.

Variable sequence number padding. While five digits is standard, very high-volume courts may use six, and lower-volume courts may use fewer. The sequence number is always zero-padded to its court's standard width.

Bankruptcy adversary proceedings. Adversary proceeding case numbers (ap type) correspond to a parent bankruptcy case in the same court. They share the court code and year but have independent sequence numbers. When querying DocketLayer for an adversary proceeding, use the ap case ID directly — it is treated as a distinct case.

Old cases, different years. The two-digit year creates a theoretical ambiguity between cases filed in, say, 1924 and 2024. In practice this is never a problem — electronic filing began in the 2000s and all cases in PACER are from that era forward.

Using case IDs with DocketLayer

The case_id field in DocketLayer API requests accepts standard federal case numbers as described above. Always include the division prefix and use lowercase for the case type code.

# Correct formats:
case_id = "1:24-cv-01234"
case_id = "1:22-bk-11068"
case_id = "2:24-cv-08765"

# Include court_code alongside case_id:
court_code = "nysd" # Southern District of New York
court_code = "deb" # District of Delaware Bankruptcy
court_code = "cacd" # Central District of California

# The court_code tells DocketLayer which CM/ECF instance to query.
# Case numbers are not unique across courts — always provide both.

Case numbers are not globally unique. Two different courts can have a case numbered 1:24-cv-01234. The court_code parameter is required in every DocketLayer query to identify which court's case you mean.

The full list of supported court codes is always available at /coverage or via the free /v1/status endpoint.

Further reading