Browse the statutory hierarchy

Walk the statutory tree one level at a time, in statutory order. Each call returns the immediate children of wherever you are. Following every node down, and every nextCursor across, reaches every section the corpus holds for that scope, so a code can be enumerated without searching.

Cost: 1 credit. A request whose filters do not fit the corpus is rejected before anything is charged. So is a filter naming a container that does not exist, a browse that returns no rows, and a failure on our side: the credit is taken only once a level with rows is ready to return, so exploring the hierarchy never costs you anything for a level that turns out to be empty.

Pass the deepest level you already know; the response returns the level below it:

• corpusType=USC -> the titles
• corpusType=USC&titleNumber=42 -> the chapters in Title 42
• corpusType=USC&titleNumber=18 -> the parts of Title 18 (a title whose chapters sit in parts, subtitles or divisions lists those first)
• corpusType=USC&titleNumber=18&part=I -> the chapters in Part I of Title 18
• corpusType=USC&titleNumber=8&chapter=12 -> the subchapters of Chapter 12 (a chapter with no subchapters lists its sections)
• corpusType=USC&titleNumber=8&chapter=12&subchapter=II -> the parts of Subchapter II (Parts I to IX)
• corpusType=USC&titleNumber=8&chapter=12&subchapter=II&part=I -> the sections in Part I (leaf)
• corpusType=CFR&titleNumber=17 -> the chapters of Title 17 (a title with subtitles, such as 29, lists them first; a title whose parts sit in no chapter lists its parts)
• corpusType=CFR&titleNumber=29&subtitle=B -> the chapters of Subtitle B of Title 29 (Subtitle A lists its parts directly)
• corpusType=CFR&titleNumber=29&chapter=XIV -> the parts of Chapter XIV of Title 29
• corpusType=CFR&titleNumber=17&part=240 -> the subparts and subject groups of Part 240 (a part with neither lists its sections)
• corpusType=CFR&titleNumber=17&part=240&subpart=A -> the subject groups of Subpart A
• corpusType=CFR&titleNumber=17&part=240&subpart=A&subjectGroup=Rules of General Application -> the sections in that subject group (leaf)
• corpusType=CFR&titleNumber=17&part=240&subjectGroup=ECFRf2ef38fa463cdfa -> the same sections (leaf), by the group's eCFR id (a subject-group node's subjectGroupId)
• corpusType=STATE&state=tx -> the state's codes
• corpusType=STATE&state=tx&code=tx_pe -> the titles of the Texas Penal Code
• corpusType=STATE&state=tx&code=tx_pe&title=5 -> the chapters in Title 5 of the Texas Penal Code
• corpusType=STATE&state=tx&code=tx_gv&title=5&subtitle=B -> the chapters in Subtitle B of Title 5 of the Texas Government Code
• corpusType=STATE&state=ca&code=ca_pen -> the parts of the California Penal Code
• corpusType=STATE&state=ca&code=ca_edc&title=1&division=1&part=11&chapter=2 -> the articles of the Education Code's Chapter 2 in Part 11 (one of its many chapters numbered 2)
• corpusType=STATE&state=ny&code=ny_jud&article=2 -> the sections in a New York article (leaf)
• corpusType=STATE&state=il&code=il_225 -> the acts in 225 ILCS, a code that is a single chapter
• corpusType=STATE&state=de&code=de_6&article=2 -> the parts of UCC Article 2 in Delaware Title 6, which sits outside any chapter
• corpusType=STATE&state=de&code=de_6&article=2&part=2 -> the sections in Part 2 of UCC Article 2 (leaf)
• corpusType=REGULATION&state=ny&code=ny_10&chapter=I -> the parts in Chapter I of 10 NYCRR
• corpusType=STATE_RULES&state=tx -> the state's court rule sets (Rules of Civil Procedure, each county's local rules, ...)
• corpusType=STATE_RULES&state=tx&code=HARRIS -> the rule sets inside Harris County's local rules, as kind: chapter
• corpusType=STATE_RULES&state=wi&code=SCR61 -> the rules of Wisconsin SCR Chapter 61, which records no level inside it (leaf)
• corpusType=CONSTITUTION -> the articles and amendments of the US Constitution
• corpusType=CONSTITUTION&article=Article III -> the sections of Article III (leaf)
• corpusType=STATE_CONSTITUTION&state=nm -> the articles of the New Mexico Constitution
• corpusType=FEDERAL_RULES -> the rule sets (FRCP, FRE, FRCrP, ...)
• corpusType=FEDERAL_RULES&code=frcp -> the Federal Rules of Civil Procedure (leaf)

Interior nodes carry a sectionCount and isLeaf: false; drill into one by passing its identifier back as the filter its kind names (title -> titleNumber on the U.S. Code and CFR and title inside a state code, chapter, subchapter, part, subpart, subtitle, division, subdivision, subjectGroup, code, article, act, and on state regulations umbrella, agency, program), keeping the filters you already passed. One listing can mix kinds: a state code lists its chapters, then the containers and loose sections outside them, a U.S. Code chapter lists any section outside a subchapter beside its subchapters, and a subchapter any section outside a part beside its parts. Read kind on each node rather than assuming it from level. Leaf nodes are sections and carry an actId for /us/statutes/section/{actId}.

A U.S. Code level does not sit at one fixed depth: Title 18's parts are above its chapters, while the parts of 8 U.S.C. ch. 12 are inside its subchapters. Pass each level a listing returned, in any order; a number that fits more than one place (part=I in a chapter whose subchapters each have a Part I) is refused with the containers to add. A CFR subject group has no stable number, so its identifier is its heading, matched case-insensitively.

A state level is listed only where the corpus records it, so which levels a code has is read from its own sections, never assumed: a code whose sections record a title, subtitle or division above their chapters (Texas titles and subtitles, California's divisions, parts and titles, Maryland's titles and subtitles) lists that level first, and each listing below it names the next level those sections record. Some codes record no level below the code (Colorado titles list their articles; Louisiana's Civil Code lists its sections directly), and note says so. A number that repeats inside one code (a California chapter 2 sits in dozens of parts) names one container only together with the levels above it; passed alone, it lists the sections of every container that carries it, flat, with a note. A state subtitle or division is never matched across titles: pass the title it sits in. State regulations that print the agency above their chapters (Maine umbrellas and agencies, Wyoming programs, Virginia agencies) list it as kind: agency, program or umbrella, and a chapter number repeated under two of them names one container only together with its agency.

Court rules (STATE_RULES) list a state's rule sets first, as kind: code. Inside a rule set, each container its rules' records name (a chapter, part, division, district or heading) is listed with the filter that drills into it as kind: chapter for the first level, then part, subchapter, article and act, whatever the publisher calls the level, with the publisher's heading as name. Keep code and every filter you already passed.

A listing larger than one response pages: truncated is true and nextCursor continues it. Pass the cursor back with the same filters until it comes back null. If note says a listing could not hold everything, it also says where the rest is.

Browse supports USC, CFR, STATE, REGULATION, STATE_RULES, CONSTITUTION, STATE_CONSTITUTION and FEDERAL_RULES, which is also what browsable says on each GET /us/statutes/coverage legend entry. The rest are dated series or share no tree, so use /us/statutes/search for those.

Federal rules are published twice: by the Judicial Conference at uscourts.gov (frcp, fre, ...) and as an appendix to the U.S. Code (uscapp_t28a_fre, ...). Each is its own rule set here, so neither is listed twice under one heading.