Cold email deliverability guide

Deliverability failures are rarely one dramatic mistake. They are three quiet ones, compounding.

Use a lookalike domain for outbound so campaign activity can never affect your primary domain. Point the correct MX records at your receiving infrastructure and add a custom tracking domain with valid TLS that matches your brand.

In MunchReach, a domain has to pass DNS verification before any mailbox on it can go active — see Email Accounts.

SPF publishes a TXT record listing which mail servers are authorized to send on behalf of your domain.

DKIM adds a cryptographic signature to each message so receiving servers can verify it wasn't altered in transit.

DMARC tells receiving servers what to do when SPF or DKIM fail, and where to send aggregate failure reports.

Connect mailboxes only on verified domains. Each mailbox is connection-tested when it is added, and the result is recorded so you can see when a connection starts failing. Scale sending by adding mailboxes rather than pushing a single mailbox harder.

Warm up for two to four weeks before campaign traffic, then ramp gradually. This conservative four-week schedule keeps reputation intact.

MunchReach's warmup engine paces this automatically and keeps running alongside campaign traffic.

Cap a healthy warmed mailbox at 30–50 emails per day. Stay under provider limits, spread sends across the day and rotate mailboxes. Scale by adding mailboxes, never by pushing one mailbox harder.

Verify every address before import, avoid catch-all domains at scale because those recipients cannot be verified, and suppress aggressively. On import, MunchReach reports every skipped row with a reason: invalid, duplicate in the file, or already in the workspace.

Keep bounce rate under 2%. Hard bounces should be suppressed immediately and never retried — a repeated send to a dead address is one of the strongest negative signals a provider tracks. Pause and investigate the list rather than the copy when bounces spike.

Every message needs an unsubscribe link or a plain-text opt-out. Opt-outs must be honoured across the whole workspace, not just the campaign that triggered them, and suppression has to apply before the next batch is queued.

Replies are the strongest positive signal a mailbox can generate, so route them somewhere they get answered. Sequences stop automatically on reply, bounce and unsubscribe, so a prospect never receives a follow-up after answering. Every reply lands in the Unified Inbox, threaded onto the original conversation.

Keep the first email plain text with at most one link and no attachments. Multiple links, tracking pixels and image-heavy HTML all add risk. Use variables with fallbacks so a missing field never breaks a sentence, and check the unresolved variable report before launching.

Three to four touches over 10–14 days is the sweet spot — after that, response rate per additional email drops sharply. Ready-made structures live in the cold email template library.

Setup in the right order: buy a sending domain, publish DNS records, warm up the mailbox, then send small, measure and scale — increasing only while bounces stay under 2%.

Watch bounce rate, complaint rate and reply rate daily during a ramp. This is what good inbox placement looks like on a properly authenticated, warmed domain sending under 50 emails per day per mailbox with a verified list.

The analytics funnel separates a delivery problem from a copy problem: delivery falling off points at infrastructure, healthy delivery with no replies points at the message.

• SPF record exists and passes alignment
• DKIM signature verifies for the sending domain
• DMARC published and monitored
• Custom tracking domain with valid TLS
• Bounce rate under 2% and complaints under 0.1%
• Every list verified before import
• Unsubscribe link or plain-text opt-out in every message
• Warmup running continuously on every mailbox