State Court Rules API: 56 Jurisdictions and How to Query Them

Vaquill AI's state court rules corpus covers 56 jurisdictions (the 50 states, the District of Columbia, Puerto Rico, Guam, the Northern Mariana Islands, the US Virgin Islands and American Samoa) and over 70,000 rules, reachable with corpusType=STATE_RULES on a monthly refresh cadence. Earlier versions of this post listed Vermont and Missouri as gaps. Both were added in October 2026, so this version spends its space on how to query the corpus and on the five jurisdictions where the data needs a sentence of explanation.

Reviewed and corrected on 12 October 2026. Counts below come from the live coverage endpoint as of that day. This is general information, not legal advice.

TL;DR

• 56 jurisdictions, over 70,000 rules, corpusType=STATE_RULES. Civil procedure, criminal procedure, appellate, evidence, professional conduct, and local rules, refreshed on a monthly cadence.
• Court rules are a separate corpus from statutes on purpose. They are promulgated by courts, not legislatures, and they carry the deadlines that filing automation and docketing products actually run on.
• Vermont and Missouri were the last two additions. Missouri carries 1,536 sections cited like Mo. Sup. Ct. R. 55.03, and Vermont carries 833 rules cited like Vt. R. Civ. P. 26.
• Colorado is built from a 2023 compilation plus the amending orders. A rule that an order changed in a way the pipeline could not apply with confidence serves its 2023 text and says so in sourceNote.
• Oklahoma and South Dakota also codify procedure into the statute book. That text stays under corpusType=STATE, and the court-promulgated rule sets sit under STATE_RULES, so search both tokens for those two.
• Point in time is a reconstruction. A citation returns today's rule by default. asOf=YYYY-MM-DD on the body endpoint rebuilds an earlier text from the changes we observed, with isBounded marking answers that rest on when capture began. If your product needs the rule as it read on a past filing date, treat the result as a lead to confirm with the court.

This is one entry in our US primary law corpus series, which covers each source separately rather than as a headline count.

If you are mapping the state layers, the companion posts are State Regulations API and State Constitutions API: 53 Jurisdictions With Article and Section Structure. The federal counterpart to this corpus is covered in Federal Rules of Procedure API: FRCP, FRE, FRAP, FRCrP, FRBP and Supreme Court Rules.

What court rules are, and why they get their own corpus token

A statute is passed by a legislature. A court rule is promulgated by a court, usually the state supreme court, under authority the legislature or the constitution gave it. They are different instruments with different amendment processes, and they answer different questions.

Statutes tell you whether you have a claim. Court rules tell you how many days you have, what the caption has to say, how many copies to file, and what happens when you miss.

That is why STATE_RULES is its own corpusType rather than a subject filter on STATE. Mixing them would put a fourteen-day deadline and a four-year statute of limitations in the same result set with no way to tell a developer which is which. Every token is listed in the corpusType reference.

The rule families

The largest single rules set we hold is Pennsylvania's, which publishes a very granular rule set. The smallest are states that publish one consolidated document per family. Neither size tells you anything about quality, so don't rank jurisdictions by rule count.

A short history: from the Field Code to your state's rule book

Court rules look like dull plumbing until you ask why every state has its own. The answer is a long tug of war between uniformity and local habit, and the Federal Judicial Center tells the story well in its pages on civil procedure before and after the FRCP.

It starts with David Dudley Field of New York, who drafted a set of procedural rules meant to be simpler than traditional common-law pleading. New York enacted them in 1848. The Field Code abolished the line between law (suits for money) and equity (suits for injunctions and other non-money relief) and gave both a single set of procedures. It caught on: by 1900, half the states had adopted it with some variations. Judges were less thrilled than legislators. The Supreme Court justices, long used to common-law pleading, said so.

Federal courts made things messier. For most of the 1800s they followed the procedure of whichever state they sat in. The Conformity Act of 1872 told them to "conform, as near as may be" to the state-court procedures "existing at the time," which meant federal practice varied from one courthouse to the next. In 1906, Dean Roscoe Pound gave a speech to the American Bar Association titled "The Causes of Popular Dissatisfaction with the Administration of Justice." The FJC quotes him saying that "[o]ur system of courts is archaic and our procedure behind the times," and lamenting "the injustice of deciding cases upon points of practice, which are the mere etiquette of justice." That speech set off the reform movement that ended with the Rules Enabling Act of 1934. The Federal Rules of Civil Procedure took effect in 1938, and the states took notice: by 1959, more than half of them had adopted the federal rules in whole or in substantial part.

So many state rule books are cousins of the federal one, with familiar rule numbers and a familiar shape. States changed the deadlines, the wording and the numbering as they went, which is why a federal rule you know can't be assumed to read the same in your client's state.

Why deadline products need this corpus specifically

Here is the argument in one worked example. A California appeal deadline isn't one rule.

{
  "query": "time for filing notice of appeal after entry of judgment",
  "corpusType": "STATE_RULES",
  "state": "ca",
  "limit": 5
}

In our 12 October 2026 run the top five results were Cal. R. Ct. 8.822, 8.104, 8.406, 8.308 and 8.393, every one titled "Time to appeal". Rule 8.822 speaks of the appellate division and gives a notice-of-appeal window that runs from the earliest of two service-based 30-day periods or 90 days after entry of judgment, so it belongs to a different court than the rules a Court of Appeal litigant reads. A deadline engine that resolves "California, notice of appeal" to a single rule has already produced a wrong answer for some of its users.

Run the same query across states, the sweep the multi-state comparison recipe automates, and the shape of the problem gets clearer:

Five jurisdictions, five citation grammars, five rule-set names, and in Massachusetts and Maryland the rule-set names show that the applicable rule depends on which court you are appealing from (for Maryland, the same search also returned Md. Rule 8-202, "Obtaining Review in the Appellate Court"). This is why filing automation built on a scraped PDF per state breaks quietly, and why the ruleSet field matters as much as the citation. The citation formats reference covers the grammars the API accepts.

What a missed deadline looks like from the inside

Docketing is the dull job that keeps lawyers out of trouble, and the people who ran it say so bluntly. A commenter who described making partner at a BigLaw IP firm and being handed the firm's docketing operation put the stakes in one sentence: "If we'd blown a court deadline, we likely would have gotten zero sympathy from the court, the client, and our malpractice-insurance carrier." The fix was low-tech. Every deadline entry got a second check, and calendaring errors dropped "to essentially zero" (dctoedt, Hacker News, July 2025).

Software speeds up entering deadlines. The lawyer still answers for them. Whatever rule your product resolves a deadline from, a human still needs a way to see which rule it was and when that text was last fetched.

Five jurisdictions worth a closer read

Every one of the 56 jurisdictions carries court rules. These five are the ones where the shape of the data needs a sentence of explanation.

Colorado is the one jurisdiction whose rules are not a single consolidated fetch. The legislature's Office of Legislative Legal Services published a consolidated volume in 2023, which is the base we use. We have not confirmed whether a later free consolidated edition exists, so ask if your product depends on that. The judiciary publishes every adopted rule change as a free order that carries the amended text. The 2023 volume is the base, and every adopted order issued after it is applied forward on top. Where an order changes a rule in a way the pipeline cannot apply with confidence, that rule serves its 2023 text and says so in sourceNote, naming the order. Read that label before relying on a Colorado rule, because a stale rule looks exactly like a current one and a deadline engine would compute from it without complaint. Eleven Colorado rules, the Rules of ICWA Procedure, come back with an actStatus of suspended and are served for reference. The value appears on the result, but the search filter does not accept suspended.

Vermont and Missouri were the last two added, in October 2026: 833 and 1,536 rules, cited the way each state's judiciary cites them (Vt. R. Civ. P. 26, Mo. Sup. Ct. R. 55.03). Vermont's judiciary publishes its amendment stream and points to a consolidated text elsewhere, so check the currency line each Vermont rule carries in sourceNote.

Oklahoma and South Dakota both codify procedure into the statute book. Oklahoma's civil procedure lives in Okla. Stat. tit. 12, and South Dakota's lives in SDCL titles 15, 19, and 23A, which the state cites that way itself: the rule 12(b) analogue, the one listing the defenses you can raise by motion, is SDCL 15-6-12(b). That text is served under corpusType=STATE, and re-serving it under STATE_RULES would be duplicate coverage. Each state's court-promulgated rule sets, which are not in the statute book, are served under STATE_RULES. For Oklahoma those include the Rules for District Courts, the Rules of the Supreme Court, and the Rules of Professional Conduct.

Query the statute-book side and you get this, under corpusType=STATE (trimmed from a 12 October 2026 lookup):

{
  "actId": "STATE_SD_T15_C6_S15-6-12",
  "citation": "S.D. Codified Laws § 15-6-12",
  "corpusType": "STATE",
  "state": "sd",
  "sectionNumber": "15-6-12",
  "title": "(b).Manner of presenting defenses and objections",
  "displayPath": "SD Code / Title 15 / Chapter 6 / Section 15-6-12",
  "lastAmendedYear": 2006
}

Read the numbering. 15-6-12 is title 15, chapter 6, section 12, and chapter 6 is South Dakota's civil procedure chapter, deliberately numbered to track the federal rules. The state has told you where the rules are by how it numbered them.

Check coverage in your build, not at query time

Whatever vendor you use, assert the jurisdictions your product depends on. GET /us/statutes/coverage is free and returns the per-jurisdiction matrix with a measuredAt timestamp, so your CI can fail when a jurisdiction you rely on loses its STATE_RULES entry. The coverage endpoint reference documents the response. That is a better contract than a number on a pricing page, and the same habit protects you from the Oklahoma and South Dakota split above.

Checking freshness yourself

GET /boards is free and lists every watchable source. State court rules boards look like this (Arizona's, as returned on 12 October 2026):

{
  "corpusType": "state_rules",
  "state": "az",
  "label": "State court rules AZ",
  "cadence": "monthly",
  "lastRetrievedAt": "2026-10-11T06:00:52.963137+00:00"
}

Two fields do the work. cadence is the registered schedule, which is monthly for state court rules. lastRetrievedAt is when a retrieval actually landed.

Registration isn't the same as a run, so a documented cadence is not proof that a retrieval landed. Poll lastRetrievedAt for the jurisdictions your product depends on and alert when it falls further behind than the cadence allows, rather than trusting a documented cadence. On 12 October 2026 the list held 51 state_rules boards. We found no board yet for Vermont, Missouri, the US Virgin Islands or American Samoa.

Who this corpus is wrong for

It is a weak fit for a litigation product that must prove the rule as it read on the day of a past filing, because asOf here is a reconstruction bounded by when change capture began and the court's own record is the authority. It is also a weak fit for a buyer whose evaluation is a jurisdiction count alone, because a count says nothing about which rules in a jurisdiction are labelled as stale.

It fits deadline calculators, docketing and filing automation, litigation agents that need to cite a rule they can link back to, and any internal research surface where "which rule governs this motion" is a real question.

FAQ

What is a state court rules API?

It is an interface returning state rules of procedure, evidence, and professional conduct as structured data rather than PDFs. Vaquill AI exposes them through POST /us/statutes/search with corpusType=STATE_RULES and a state filter, plus direct retrieval by actId. Each result carries the citation, the rule set it belongs to, and the path through the rules hierarchy.

How many jurisdictions are covered?

56: the 50 states, the District of Columbia, Puerto Rico, Guam, the Northern Mariana Islands, the US Virgin Islands and American Samoa, holding over 70,000 rules as of 12 October 2026. Vermont and Missouri, which earlier versions of this post listed as gaps, were the last two added.

Where do Vermont and Missouri rules come from?

Both were added in October 2026: Vermont with 833 rules and Missouri with 1,536 sections. Each rule is cited the way the state's judiciary cites it, and each carries its source details in the response fields. Read sourceNote on a Vermont rule for its currency line, and confirm anything deadline-critical with the court.

How does Colorado work, given the state publishes rule changes as orders?

The 2023 consolidated volume is the base, and each adopted rule-change order issued since is applied forward on top of it. A rule that an order changes in a way we cannot apply with confidence serves its 2023 text and names the order in sourceNote, so a stale rule is labelled instead of passing as current.

Are Oklahoma and South Dakota rules available in the API?

Yes, under two tokens. Both states codify procedure into the statute book, Oklahoma in Okla. Stat. tit. 12 and South Dakota in SDCL titles 15, 19, and 23A, and that text is under corpusType=STATE. South Dakota's rule 12(b) analogue is SDCL 15-6-12(b), retrievable at actId STATE_SD_T15_C6_S15-6-12. Each state's court-promulgated rules are served under corpusType=STATE_RULES.

How often do state court rules refresh?

State court rules boards are registered on a monthly cadence. Because a registered cadence isn't proof a run happened, GET /boards reports lastRetrievedAt per jurisdiction, which you compare against the cadence yourself. The endpoint is free.

Can I get the version of a rule as it read on a past date?

For many dates, yes, as a rebuilt text. Send the date as asOf on the body endpoint for a rule and the pipeline works backward from the first change it recorded after that day. If capture began after your date, the answer says so through isBounded or returns unavailable. The court's own order archive remains the record to check, because no published editions of state court rules are stored here.

How do I tell which rule set a result belongs to?

Use the ruleSet field, which names the set the rule sits in, such as Rules of Civil Appellate Procedure or Maine Rules of Appellate Procedure. This matters in states where the same subject is governed by different rules depending on the court level, as with Massachusetts appellate division appeals and Maryland appeals from the District Court.

Priyansh Khodiyar

Co-Founder & CTO

Priyansh leads engineering and AI at Vaquill AI: the pipelines that pull statutes, regulations and court rules from every US jurisdiction's official publisher, and the REST API, MCP server and open dataset that serve them.