Offsite conversions are actions that happen on an advertiser’s website or app after a user clicks or views a Meta ad, as opposed to on-platform actions like lead form submissions or Meta Shop purchases. They include standard events like purchases, sign-ups, and app installs tracked via the Meta Pixel or Conversions API. Optimizing for offsite conversions requires sufficient event volume, Meta recommends at least 50 conversion events per ad set per week for the algorithm to exit the learning phase. Advertisers with low conversion volume are advised to optimize for a higher-funnel event like Add to Cart first, then shift to Purchase once data volume increases.