OutMass

What OutMass is

OutMass is a Chrome and Edge extension that adds mail merge and mass email tools to Outlook on the web. It supports Microsoft 365 and Outlook.com accounts, and sends messages through the user’s own mailbox using Microsoft Graph. Contacts can be imported from CSV and personalized with merge tags such as {{FirstName}} and {{Company}}. Campaign tools include open and click tracking, reports, scheduled sending, templates, and A/B testing. A campaign can send one automatic follow-up to recipients who have not replied or opened the email; reply detection runs every six hours. An optional OneDrive connection creates view links for selected files, which remain in the user’s OneDrive. The extension interface is available in 13 languages. The free plan allows 250 emails per month; Starter is $9 a month for 2,500 emails, and Pro is $19 a month for 10,000. Microsoft sending limits also apply. OutMass says it does not read inbox messages or store received emails or Microsoft passwords.