CourtListener is a legal database operated by the Free Law Project, a nonprofit group described on the "About" page as striving to "provide free access to primary legal materials." The case law content External of CourtListener is similar to other free online databases, including:
U.S. Supreme Court Opinions – 1791 to the present
U.S. Federal Appellate Court Opinions – 1920s to the present for most circuits
U.S. Federal District Court and Bankruptcy Court Opinions – coverage dependent on district
U.S. State Supreme and Appellate Court Opinions – coverage dependent on state
To perform a search in CourtListener, simply enter your keywords or citation information into the search box on the homepage. If you would prefer a more focused search, simply click the "Advanced Search External" link underneath the search box, or select the "Opinions" menu at the top left-hand side of the page and click "Advanced Search" from the drop-down menu. The results page allows for several limiting options, including jurisdiction, the precedential status of the source, filing date, judge, case name, citation, docket number, and more.
CourtListener opinion pages offer several helpful features. First, opinions include pagination information, which can assist researchers in finding the opinions in print resources. Additionally, CourtListener includes an "Authorities" list for each opinion, providing links to the opinions cited within the opinion of interest. The most helpful aspect of opinions found in CourtListener, though, is likely the "Cited By" feature, which provides links to other opinions available on CourtListener that cite to the opinion you are currently viewing, arranged by number of times those opinions are cited. Much like the Google Scholar "How Cited" feature, Cited By is very helpful for getting a feel for how an opinion has been treated by other courts, but it is not considered as authoritative as subscription options available.
CourtListener also provides case information beyond just opinion text. Researchers might be interested in the oral arguments External collection provided by CourtListener, which currently focuses on the U.S. Supreme Court and Federal Appellate Courts. For those interested in records and briefs filed in federal courts, CourtListener's RECAP Archive External houses selected documents from the PACER database, which contains "case and docket information online from federal appellate, district, and bankruptcy courts."