Hasher-Matcher-Actioner

Hasher-Matcher-Actioner (HMA) is Meta's open source reference service for the whole hash pipeline. It hashes incoming media with PDQ, vPDQ or PhotoDNA, matches against hash banks you load (NCMEC, GIFCT, StopNCII or your own), and fires an action (webhook, label, queue entry) when it hits. It's a Python service with an admin UI and a REST API, and it's built to be dropped in front of an upload flow.

Version 2 is a lighter rewrite that runs in a single container. It's the fastest route to a working hash match if you don't want to build one.