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Deliverability & warmup

Deliverability is whether your email actually lands in the inbox instead of spam. The biggest lever for a new sending domain is warming — ramping your daily volume up gradually so mailbox providers learn to trust you. This guide explains how RadarSend warms a domain and how to keep your reputation healthy.

What warming is and why it matters#

A brand-new sending domain has no reputation, so mailbox providers (Gmail, Outlook, Yahoo, and the rest) treat a sudden burst of email from it as suspicious — and route it to spam or reject it outright. Warming avoids that by capping how many emails the domain sends per day and raising that cap in steps as a clean track record builds.

In RadarSend a new domain starts around 200 emails/day and reaches full speed (50,000/day) over about eight weeks. You compose and schedule broadcasts as normal — RadarSend just paces how much actually goes out each day. A broadcast larger than today’s cap automatically spreads over several days, sending a little more each day as the cap grows.

Start warming#

Warming lives on each sending domain’s Details page. Go to Settings → Sending → Email domains → your domain → Details. There’s a How warming works explainer there if you want the full walkthrough.

Warming is set per domain × sending service: each sending service connected to a domain gets its own independent track, so if you send the same domain through two sending services, each warms separately. On the Details page, the header strip shows a Service tracks count, and each track appears as its own row with its own controls.

A track that isn’t warming shows Not warming and a Start warming button. Click it to begin. There’s no plan to pick: every domain climbs the same eight tiers, from 200/day up to 50,000/day (200 → 500 → 1,000 → 2,500 → 5,000 → 10,000 → 25,000 → 50,000), over about eight weeks of steady sending. At the end it switches to full speed on its own.

Once it’s running, each track shows where it is:

  • Tier 3 of 8 (for example) while it climbs, with an estimate of how long until full speed.
  • Warmed once today’s cap already covers your largest recent audience.
  • Not advancing if it has spent more than a full tier’s time at one tier without moving up. It needs more sending volume to climb.
  • Paused while you’ve paused it.

Use Pause to hold a track. You’ll be asked for a reason, and paused days don’t count, so Resume warming picks up exactly where you left off. Stop warming early… ends warming and sends at full volume. If the track hasn’t passed both checks below yet, you’ll be asked to confirm Exit warming early? first. Do that only if the domain already has a good reputation, for example because it was warmed somewhere else.

How a track moves up: the tier is earned. Each night RadarSend checks every warming track and moves it up one tier when both are true: it has spent at least 7 days at the current tier, and it has sent enough there, roughly one full day at that tier’s cap. The domain only warms if you send: a track left idle holds its tier until it sends again. If your list is small, the track stops climbing once the current cap already covers your largest recent audience, and holds there rather than ramping toward volume you’ll never send. If your list grows past that cap, warming picks back up and climbs to fit it.

Track your reputation#

The domain Details page is your reputation dashboard. At the top, a metric strip shows First seen, Identities linked, Service tracks, and the Gmail spam rate once Google Postmaster Tools is connected.

Three areas track deliverability health:

  • Reputation signals — rolling 14-day averages captured daily, charted over the last 30 days: Hard bounce (notification threshold 1.0%), Complaint (0.05%), Click rate (no threshold), and Unsubscribe rate (0.5%). If bounces or complaints run hot, you get a notification and a Watch flag — but that’s a heads-up only; it doesn’t freeze your warming ramp.
  • Gmail signals (Google Postmaster Tools) — what Google reports for mail it received from this domain: the Gmail spam rate over 14 days, charted against Google’s 0.1% recommended and 0.3% limit lines; SPF, DKIM, and DMARC pass rates; and Gmail delivery errors by reason (for example, rejected for low domain or IP reputation, or listed on a blocklist). Each figure is dated by the day Google reported it. Google no longer publishes a domain or IP reputation grade, so RadarSend doesn’t show one.
  • Gmail sender requirements — Google’s checklist for bulk senders (SPF and DKIM, DMARC alignment, TLS, spam rate, one-click unsubscribe, and the rest), with Google’s verdict for each.

Connect Google Postmaster Tools: go to Settings→Google Postmaster (or click Set up on the Connect Google Postmaster step in the domain’s setup checklist) and authorize your Google account. One Google account covers the whole workspace, and every domain verified in that account’s Postmaster Tools is picked up automatically — add and verify your sending domains at postmaster.google.com first. RadarSend checks for new figures every few hours; Google usually reports a day or two behind. The connection is read-only — RadarSend never acts on this data automatically, and you can Disconnect at any time.

Deliverability best practices#

  • Send only to people who opted in. Permission is the foundation of deliverability — never buy or scrape lists. High complaint rates from unwanted mail sink your reputation fast.
  • Keep your list clean. Remove addresses that hard-bounce or never engage. Poor list hygiene drives up bounces, which mailbox providers penalize.
  • Authenticate your domain. Set up SPF, DKIM, and DMARC so inboxes know your mail is legitimate — see Authenticate your sending domain.
  • Honor unsubscribes and subscription preferences. Make opting out easy and instant — see Email types & subscriptions.
  • Watch your bounces. Keep an eye on the hard-bounce signal and let suppression do its job — see Bounces & suppression.

Common issues#

  • “No reputation data yet.” Signals populate only after your first sends through the domain. Send a broadcast and check back the next day.
  • “My warming track isn’t moving up.” Advancement needs both time and volume at the current tier — a track that isn’t sending enough holds its tier. If your list already fits the current cap, the track shows Warmed and won’t climb further. That’s healthy.
  • Gmail data is stale or unavailable. If RadarSend can’t reach Google Postmaster Tools, you’ll see a banner — go to Settings→Google Postmaster and click Reconnect to refresh your Google credentials.
  • The checklist says “Add this domain in Google Postmaster Tools.” Your Google account is connected, but this domain isn’t in its Postmaster Tools, or isn’t verified there yet. Add and verify it at postmaster.google.com and RadarSend picks it up automatically.
  • “Connected. Google hasn’t reported Gmail data for this domain yet.” Google only reports once a domain sends enough mail to Gmail users, and it runs a day or two behind. Days without a report show as gaps, not zeros.
  • I want to send full volume immediately. You can stop warming early, but sending at full volume on a cold domain can hit receiver reputation thresholds quickly. It’s not recommended without prior reputation.

Good to know#

  • Warming is per domain × sending service. The same domain sent through two sending services warms independently on two tracks.
  • You still schedule normally. Warming only paces delivery; broadcasts larger than today’s cap spread across days automatically.
  • Reputation signals are advisory, not gates. A Watch flag warns you when bounces or complaints are elevated, but warming keeps advancing on time and volume — you decide how to respond.
  • Pausing is free. Paused days don’t count against your progress; resume right where you left off.
  • Warming finishes on its own. Once a domain has genuinely earned the top tier, the cap comes off and it sends at full speed from then on. You can also stop early at any time with Stop warming early….
  • Use a subdomain for marketing (e.g. news.acme.com) so bulk-sending reputation stays separate from your primary domain’s transactional mail.