Use text-only emails. Plain text (rather than heavy HTML) reduces spam signals and improves deliverability.

Limit images and links, especially in the first email. On SMTP mailboxes, our built-in Global Custom Domain Tracking automatically replaces links with safe alternatives, so you don't need a third-party tracking domain.

Keep signatures minimal. Avoid extra domains, links, phone numbers, and photos, which spam filters weigh against you.

Avoid spam words. Check your copy — including the signature and any unsubscribe text — for trigger words.

Include a clear unsubscribe option in the email body. Maildoso's sending relay strips List-Unsubscribe/List-Unsubscribe-Post headers on every plan, so a header-based unsubscribe won't work — always include a visible, functional unsubscribe link or opt-out instruction directly in the body text to comply with regulations and avoid spam filters. For the full reasoning (including why PTR and DKIM work the same way) see Does Maildoso support List-Unsubscribe (one-click unsubscribe) headers? in this collection.

Warm up properly and ramp gradually. Sudden volume spikes from a new domain are the fastest way to hurt reputation. See What's the daily email limit per email account? and How warmup works and how to start it.

Email clean, valid lists. High bounce rates and spam complaints damage reputation quickly.

Rotate campaigns and use spintax. Regularly refresh your copy and use plenty of spintax for variability.

Watch your scores. Track each mailbox's Google Score and Microsoft Score in the dashboard as you go — see Understanding your mailbox reputation scores. Emailing Microsoft recipients has its own tips: Landing in the inbox with Outlook and Microsoft recipients.

Pause mailboxes with high spam placement. If a mailbox shows poor placement during warmup, exclude it from campaigns until scores recover.