How to check deliverability before sending a Lemlist campaign

Lemlist is one of the cleanest sequencer UIs on the market. The dashboard shows opens, replies, bounces, a Lemwarm health score, and neat per-step conversion funnels. What it does not show — and this is the trap — is where any of those messages actually landed. Primary tab, Promotions, Spam, or a Microsoft Junk folder: to Lemlist they all count as "sent".

What Lemlist actually does well

Lemlist's strengths are real and worth stating plainly. Lemwarm is one of the older warm-up networks, so it has more aged mailboxes in its rotation than most competitors. Multi-sender campaigns let you rotate through several connected inboxes cleanly. Sequences with conditional branching on open/reply are genuinely useful. Liquid syntax personalisation via {{firstName}} and image-based variables helps a campaign feel less templated.

None of that is in dispute. The problem is that none of it answers the one question a sender needs answered before pressing Launch: will the next 300 messages land in the inbox?

What Lemlist does not tell you

The Deliverability panel under Settings → Email provider surfaces a Lemwarm score, a recent-bounce count, and whether SPF/DKIM are detected. That is the sum of placement signal Lemlist gives you. There is no per-provider breakdown — Gmail vs Outlook vs Yahoo folder routing is invisible. There is no content analyser, no SpamAssassin score, no DNSBL check for your tracking domain. The reply rate you see is a lagging indicator: by the time it has tanked, you have already sent 500 emails to Spam.

The 5-minute pre-send routine

Run these five checks before every new sequence. The first three are one-off per sending domain; the last two are per campaign.

1. Verify authentication on the sending domain. In Settings → Email provider → Deliverability Lemlist shows a green/red auth status. If it is red, fix SPF/DKIM/DMARC before anything else. A missing DMARC record alone can push 30–50% of Gmail volume into Spam.
2. Check sending inbox age. Inboxes under 4 weeks old should not be on a cold sequence, Lemwarm or not. Lemlist will happily let you connect a 3-day-old Workspace mailbox and start sending — the tool does not gate this.
3. Run an external placement test. Send one representative message of your sequence through an inbox placement tool against a Gmail/Outlook/Yahoo seed set. That is the only report that tells you the folder a real ISP just routed the email into.
4. Review Lemwarm health. Anything under 80% means the mailbox is not ready for cold volume. Keep warming, or rotate to another connected inbox.
5. Trial send to 5 recipients. Use colleagues on Gmail, Outlook and a European provider. If the message lands in Spam on any of them, the sequence is not ready.

Reading Lemlist's deliverability panel

The panel reports four numbers that are easy to misread:

• Lemwarm score — percentage of warm-up emails that reached inbox in the network. Useful as a directional signal, but Lemwarm recipients are other Lemwarm users, not real prospects. A 95% score does not translate directly to Gmail Primary.
• Bounce rate — anything above 2% is a problem. Above 5% and Gmail will start throttling regardless of everything else.
• Reply rate — the most reliable placement proxy Lemlist has. If reply rate drops below 2% on a previously-working sequence, you are almost certainly being filtered.
• Spam complaint rate — target is under 0.1%. Gmail's 2024 sender rules put the threshold at 0.3%; above that your reputation collapses fast.

Configuring a custom tracking domain

Lemlist defaults to a shared tracking domain (previously lemlist.com, now trk.lemlist.com variants). That shared domain is shared with every other Lemlist customer, including the ones sending low-quality cold mail. If they pick up a DNSBL listing, every link in your message carries that stain.

Under Settings → Custom domain Lemlist lets you point a CNAME — for example track.yourdomain.com — at their tracking endpoint. Use it. Two conditions: the tracking subdomain should be at least 30 days old, and it must never be shared across unrelated brands or campaigns.

Signs a Lemlist campaign will fail

Five patterns that reliably predict a Spam-bound sequence, in rough order of severity:

• Lemwarm score under 70% on the sending mailbox. Postpone and warm for another two weeks.
• Sending domain is the same as your corporate mail domain and has never been warmed for cold outreach. Move to a dedicatedget.yourbrand.com subdomain or a fresh domain.
• No DMARC record, or DMARC stuck on p=none for months. Move to p=quarantine once aggregate reports look clean.
• Gmail shows "This message seems suspicious" or similar banners on your trial sends. That is Gmail telling you the reputation score is below its threshold.
• Bounce rate above 3% on the first 100 sends. List is unverified. Stop, validate the list, restart.

When to pause Lemlist sends mid-campaign

Pause immediately if bounce rate crosses 5% across the last 200 sends, if Gmail shows a filtering banner, or if reply rate drops to under half of the first-day rate. Lemlist's auto-pause triggers only on bounces, which is too late — placement collapse often precedes the bounce spike by several days.

Complementary tools

Three tools that close Lemlist's reporting gaps without overlapping its core functionality:

• Inbox placement tester — per-provider folder routing, run before every campaign and whenever a sequence change goes live.
• dmarcian or Postmark DMARC — aggregate DMARC report viewer. Shows which senders are failing alignment from your domain.
• MXToolbox — DNS health, blacklist status, MX record sanity. Thirty seconds per domain, catches issues Lemlist never surfaces.

Frequently asked questions