Is MergeMail safe?

MergeMail reads Gmail compose content — body, subject, and all recipients — and sends it to mergemail.co before each email is sent.

When a user composes or previews a Gmail message, the extension collects the full email body, subject line, and all recipient addresses (To, Cc, Bcc) via the Gmail compose API. This data is POSTed to www.mergemail.co/campaigns/prepare through the extension's background script on the presend event. The user's Gmail address is also transmitted as a URL parameter when the extension loads its sidebar iframe.