Mail Sync

A personal tool that copies one person's work email into their own personal inbox.

Mail Sync is a private Google Apps Script written for and used by a single person. It replaces Gmail's “Check mail from other accounts” feature, which Google closed to new setups in early 2026 and retires entirely in January 2027.

What it does

On a timer, it reads new messages from one Gmail mailbox and inserts a copy into a second Gmail mailbox. Both mailboxes belong to the same person. The copy keeps the original sender, recipients, date and message ID, so it reads like the original rather than a forward.

What it is not

• Not a product, not offered to anyone else, and not available to sign up for.
• Not a mailing tool: it cannot send, reply to, forward or delete anything.
• Not backed by a server. There is no backend, no database and no operator but the user.

Access it requests

Read-only access (gmail.readonly) to the source mailbox, and permission to insert messages and manage labels in the destination mailbox. Nothing more.