Deliverability best practices

Deliverability — whether your emails land in the inbox or the spam folder — comes down to four things: a verified domain, a warmed-up sending reputation, a clean list, and content that doesn't trip spam filters. This article covers each one. If you haven't verified your sender domain yet, start with Verifying your sender domain — nothing else on this page matters until that's done.

Warm up a new sending domain

Mailbox providers are suspicious of domains that go from zero to thousands of emails overnight — that's what spammers look like. If your domain (or subdomain) hasn't sent marketing email before, ramp up your volume gradually so providers can build a positive history for it.

A conservative warm-up schedule looks like this:

1. Week 1: Send to your most engaged contacts only — recent customers and recent subscribers. Keep sends in the low hundreds per day.
2. Week 2: Roughly double your daily volume if engagement holds (opens are healthy, complaints and bounces are low).
3. Weeks 3–4: Keep doubling until you reach your normal volume.
4. If problems appear — a spike in bounces, complaints, or emails landing in spam — drop back to the previous week's volume and hold there until metrics recover.

The exact numbers matter less than the shape: start with your best audience, grow steadily, and watch your broadcast reports after every send.

Keep your list clean

Spam complaints and bounces are the two signals that damage a sender reputation fastest. List hygiene keeps both low:

• Only email people who opted in. Never import purchased or scraped lists — they are full of dead addresses and spam traps, and one bad send can undo months of reputation.
• Make unsubscribing easy. Every email must include the *|UNSUBSCRIBE_URL|* merge tag. Someone who can't find the unsubscribe link clicks "mark as spam" instead — which hurts you far more than an unsubscribe does. See the merge tags reference.
• Segment out inactive contacts. Contacts who haven't opened or clicked in a long time drag down your engagement metrics. Move them to a re-engagement segment, send a "still want to hear from us?" campaign, and stop emailing the ones who don't respond. See Lists and segments.
• Don't re-import your way around suppression. See the section on suppressed contacts below.

Why suppressed contacts stay suppressed

When a contact unsubscribes, hard-bounces, or marks your email as spam, Reach suppresses them: they stay in your audience, but Reach will not send email to them again. This is deliberate, and it protects you:

• Unsubscribed contacts: emailing someone who opted out is a legal problem (CAN-SPAM, GDPR) and a fast route to spam complaints.
• Hard bounces: the address doesn't exist. Repeatedly sending to dead addresses is a classic spammer signal, and mailbox providers penalize it.
• Spam complaints: this person told their mailbox provider your email is spam. Emailing them again guarantees another complaint.

Deleting and re-importing a suppressed contact does not lift the suppression — Reach keeps them suppressed on purpose, so an import mistake can't wipe out your compliance record. If a contact genuinely wants back in, they need to opt in again themselves. For the full picture of subscription states, see Subscription status, consent & unsubscribes.

Avoid spam filters: content

Modern spam filtering is mostly about reputation and engagement, but content still matters at the margins:

• Write a subject line that matches the email. Misleading subjects drive complaints. Avoid all-caps, excessive punctuation (!!!), and heavy "FREE / ACT NOW" phrasing.
• Balance images and text. An email that is one giant image with no real text is a classic spam pattern. Keep a healthy amount of live text.
• Link to domains you control. Avoid link shorteners (bit.ly and similar) — spammers use them to hide destinations, and filters know it.
• Include your physical mailing address. It's legally required in most jurisdictions. Use the {{ company_address }} merge tag in your footer — it pulls from your Brand Kit, so updating it once updates every email. See Brand Kit and Reach.
• Send a plain, honest email. If in doubt, write like a person, not a billboard.

Avoid spam filters: infrastructure

• Verify your domain with SPF and DKIM — see Verifying your sender domain.
• Send from a consistent from-address. Changing your from-address frequently resets the recognition you've built with recipients and their providers.
• Use a real reply-to address and read the replies. A no-reply address suppresses engagement signals and frustrates recipients. Replies are a strong positive signal.
• Keep a steady sending cadence. Long silence followed by a sudden blast looks like a compromised account. Regular, predictable volume builds reputation.

Watch your metrics

After each send, check your broadcast reports. As rough guides: keep hard bounces under about 2% and spam complaints under about 0.1% per send. If either climbs, pause, tighten your segmentation to engaged contacts, and review where the affected addresses came from before sending again.