Deliverability comes down to sending like a real person, to the right audience, and protecting your sender reputation. Maildoso is built for targeted, automated B2B cold email — campaigns to relevant corporate business addresses, for example promoting your SaaS or other business services. Here are the habits that make the biggest difference.
Content and formatting
First email: plain text, no links. Plain text (rather than rich HTML with images and buttons) reduces spam signals. Links and booking or file links are fine in follow-ups once the thread exists — on SMTP mailboxes they go through our built-in Global Custom Domain Tracking, so you don't need a third-party tracking domain.
Never use open tracking. The tracking pixel is an invisible image, which is a strong spam signal; turn open tracking off for the whole sequence in your sequencer. Click tracking on plain links is acceptable.
Keep signatures minimal. Avoid extra domains, links, phone numbers and photos — at volume they become a footprint that filters learn.
Avoid spam words — check your copy, signature and unsubscribe text for trigger words.
Include an unsubscribe line in the email body. Every email must include a functional unsubscribe link or a clear opt-out sentence in the body. Our sending relay strips List-Unsubscribe / List-Unsubscribe-Post headers on every plan, so a header-based unsubscribe never reaches the recipient — see Does Maildoso support List-Unsubscribe headers?
Rotate copy and use spintax. Identical copy sent for weeks gets "footprinted" by filters; if placement drops on a long-running campaign, small rewrites restore it more often than infrastructure changes.
Sending habits
Warm up properly and respect the volume limits. 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. Authentication (SPF, DKIM, DMARC) is configured for you on Maildoso domains, but even perfect authentication doesn't replace warmup.
Email clean, verified lists. Keep your bounce rate below 2%; high bounce rates and spam complaints damage reputation quickly.
Stay B2B-only. Don't send to personal/consumer addresses (gmail.com, outlook.com, yahoo.com and similar) — they're likely to land in spam and can lead to suspension of service under our terms. See Landing in the inbox with Outlook and Microsoft recipients and High bounce rates or spam placement when emailing Gmail recipients.
Watch your scores and Insights. Track each mailbox's Google Score and Microsoft Score in the dashboard, and use the Insights page (warmup pool quality, cold sending hygiene, warmup and cold volume per mailbox) to spot problems early — see Understanding your mailbox reputation scores and Understanding your Warmup & Deliverability Insights.
Rest mailboxes with high spam placement. If a mailbox shows poor placement, exclude it from campaigns until its scores recover. Sending IPs rotate automatically on our side, so a Spamhaus or other listing is addressed by proper warmup, not by IP changes.
What our terms allow — and what we can't do
Allowed: targeted, automated B2B campaigns to verified corporate business addresses that follow the guidelines above. The domain side of compliant sending is covered in What are the best practices for configuring domains?
Maildoso doesn't certify the sources of your email lists, the countries of your recipients or your complaint rates, and policy exceptions can't be approved. Make sure your lists are clean and compliant with the regulations that apply to you.
For the complete playbook, read the Maildoso deliverability guide, or book a free Deliverability audit from the top bar of your dashboard.