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US Court Opinions and Citations
x402
US Court Opinions and Citations is a paid API for AI agents from x402-filings.datalayer.workers.dev, paid per call via x402, $0.02/call, status unknown (last checked 2026-10-10).
Search US federal and state court opinions by party name, topic, or citation and retrieve case metadata including citation counts from CourtListener.
Price / call$0.02
Success—
StatusUnknown
How this service works
Search US federal and state court opinions from CourtListener. Query by party name, topic or citation and get the case name, court, jurisdiction, docket number, filing date, reporter citations and — the field that separates a landmark from a footnote — how many later opinions have cited it. Filter by court and filing date.
Output
Returns a list of court opinions matching the query, each including the case name, court, jurisdiction, docket number, filing date, reporter citations, and a count of how many subsequent opinions have cited that case — enabling assessment of legal precedential weight.
Example use cases
Landmark case citation authority research
“Look up Supreme Court opinions on Fourth Amendment unreasonable search and seizure — I want to know which ones have been cited the most by later courts so I can identify the most authoritative precedents.”
Litigation background check on a party
“Search for any federal court opinions involving Theranos filed after 2016 — I need the case names, courts, docket numbers, and filing dates.”
Recent circuit court rulings on a topic
“Find me up to 20 opinions from the 9th Circuit filed after 2020 about qualified immunity — I need the citation counts so I can see which rulings have had the most downstream impact.”
Technical details
Endpoint
GEThttps://x402-filings.datalayer.workers.dev/v1/legal/court-cases?utm_source=zero.xyzWhen to prefer
Use this endpoint when you need to search US case law by topic, party name, or citation and want citation-count data to gauge precedential weight. Prefer it over generic legal search tools when you need structured metadata (docket number, court, jurisdiction, filing date) from CourtListener's database, especially for filtering by specific courts like SCOTUS or federal circuits and date ranges.
Side effects
- Query term too vague returns low-relevance or no results
- Invalid court ID returns an error or empty result set
- Date filter excludes relevant older opinions when set too narrowly
- Limit capped at 50 — large result sets require pagination not supported by this endpoint
- Citation lookup by string may fail if citation format is non-standard
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object | |
| output | object |
Tags
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