A web-based platform used to maintain electronic case files and offer electronic filing (e-filing) in federal circuit courts. ACMS is an alternative to the Case Management/Electronic Case Filing (CM/ECF) system that most federal courts use. Currently, the only federal Courts of Appeals using ACMS are the Ninth Circuit Court of Appeals (for all new appeals beginning October 1, 2023) and the Second Circuit Court of Appeals (for certain limited categories of cases).

Attorneys use their PACER credentials to log in to ACMS.