What is a hosted mailbox?
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A hosted mailbox is an inbox that lives on someone else's servers. Instead of running your own mail server in-house, you rent space from Google Workspace, Microsoft 365, Fastmail, or another provider. They handle storage, spam filtering, security, backups, and uptime.
Why this matters for email senders: hosted mailboxes are for receiving email, not sending marketing or transactional campaigns. If you're building a newsletter or sending customer emails at scale, you need an Email Service Provider (ESP), not just a hosted mailbox. Using your Google Workspace account to send bulk email breaks most ESPs' terms of service and will wreck your domain reputation fast. But That said, hosted mailboxes and sending infrastructure work together. Your domain's SPF record needs to authorize both your hosted mailbox provider (so your personal emails authenticate) and your ESP (so your campaigns authenticate). If you set up DMARC without authorizing your hosted mailbox, your team's everyday emails might fail authentication checks.
Most businesses use hosted mailboxes for internal communication (your team's @yourcompany.com addresses) and a separate ESP for customer-facing email. That separation keeps your team's inboxes functional even if a marketing campaign triggers spam complaints.
Not sure if your setup authorizes both correctly? Check your domain's SPF record with our free SPF checker.
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