01
New domains land in spam
A fresh domain with zero history looks like a bot to Gmail and Outlook. First campaign from an un-warmed inbox — 4× more likely to land in junk than primary.
open rates tank 60–80%
ProductEmail WarmupLive
Warm inboxes.
Land every send.
Sleep at night.
Automated email warmup that runs in the background — real conversations, gradual volume, and a sender reputation score that climbs every day. Stop burning domains. Start landing in the inbox.
14-day free trial · No credit card · 279+ teams warming daily
94
Reputation scorehello@yourdomain.com+18 this week
Warmup feed · todayLive
- EWDelivered to primary · Gmail2 minutes agoInbox
- EWReply captured · Outlook6 minutes agoReply
- EWSaved from spam · Zoho11 minutes agoRescued
Saved from spamSince warmup began
99%Median inbox placement across warmed accounts
2–4 wksTo fully warm a brand-new domain
24/7Hands-off automation — sends, replies, scoring
AES256Bank-grade encryption on every credential
Supported providers
If your inbox sends email, Sendlio warms it.
Google WorkspaceGmail · GSuite
Microsoft 365Outlook · Exchange
Zoho MailBusiness mail
iCloud MailApple accounts
Yahoo MailPersonal + business
Custom SMTPAny IMAP/SMTP host
The problem
Cold email dies before send — and most never know why.
Providers trust senders with history. They flag senders without one. Skip warmup on a fresh domain and your first campaign is dead on arrival — no second chances once you're marked as spam.
02
Manual warmup steals your week
Emailing yourself, pulling replies out of spam, ramping up by hand — 20 minutes per inbox, every day. Ten inboxes, three work hours a week gone.
~150 hrs / year per team
03
No signal, no reputation
No health score. No deliverability dashboard. Your inbox dies silently — and you find out the same way prospects do: when nobody replies.
pipeline collapse mid-quarter
What you get
Not features. Results.
Customer-facing outcomes, not internal toggles. Three things that change the day you flip warmup on.
Outcome 01 · Inbox placement
From spam folder to primary tab — on autopilot.
Sendlio sends natural emails between your inboxes and a private warmup network, then pulls any that land in spam back into the inbox. That rescue is the exact signal Gmail, Outlook, and every major provider use to mark a sender as trustworthy.
- Every spam-save logged. Count climbs daily — proof reputation improves.
- No tricks, no shortcuts. Real senders, real replies, real reputation earned.
- Works on every major provider. Gmail, Outlook, Zoho, Custom SMTP.
Inbox placement · liveLive
SpamBefore
EW
Quick intro — 2 min?From · yourdomain.com
EW
Following up on my noteFrom · yourdomain.com
PrimaryAfter
EW
Quick intro — 2 min?From · yourdomain.com
EW
Following up on my noteFrom · yourdomain.com
Saved from spamSince warmup began · +12 today
847Outcome 02 · Automated ramp
Volume that grows like a real account — never a blast.
A brand-new domain sending 200 emails on day one is an instant spam flag. Sendlio ramps slowly, day by day, from a safe baseline you choose. Grows the way a real inbox does — gradually, naturally, invisibly.
- Set it once. Starting volume, daily increase, sending hours — walk away.
- Human send spacing. Minutes apart inside business hours — never bursts, never 3am.
- Pause, resume, adjust. Real calendar days drive ramp — stopping always safe.
Ramp-up, day by dayVolume climbs from a safe baseline on day 1 to full sending by day 30 — the same pattern a real human inbox follows. No bursts. No flags.Live ramp
Outcome 03 · Health score
Know your reputation at a glance. Every inbox. Every day.
One rolling health score per account — built from reply rate, bounce rate, and spam-rescue count — tells you whether an inbox is safe for campaigns. No guessing. No finding out two weeks late. Just a single number to trust.
- Daily updates per inbox. Watch score climb in real time.
- Historical trend. Spot a degrading account weeks before it hurts pipeline.
- Built for 50+ inboxes. One screen, every account, every score.
One score. Every inbox.A rolling health score per account, a weekly trend line, and the running count of spam saves. Catch a degrading inbox weeks before it shows up in pipeline.Live dashboard
How it works
Four steps. Zero babysitting.
Connect an inbox, flip a toggle, walk away. Sendlio handles validation, ramp-up, sending, reply capture, and daily reporting on its own.
STEP 01
Connect your inbox
Plug in Gmail, Outlook, Zoho, or any SMTP/IMAP account. We test the connection live and encrypt credentials with AES-256.
30 secondsSTEP 02
Turn warmup on
One toggle. Use recommended ramp-up or set your own starting volume and daily increase.
One clickSTEP 03
Let it run
Real emails send and receive on a human schedule. Replies tracked. Spam-saves logged. You do nothing.
24/7 automaticSTEP 04
Watch score climb
Daily health score shows reputation building live. Launch campaigns when the number says you're ready.
Live dashboardWhy Sendlio
Not every warmup tool is built the same.
Most warmup tools share a queue with your campaigns, give you a vague reply counter, and hope for the best. Sendlio was built by operators who got burned — so deliverability, security, and visibility are defaults, not upsells.
| Capability | Basic warmup tools | Sendlio Warmup |
|---|---|---|
| Daily ramp-up | Fixed schedule | Configurable per inbox |
| Reply tracking | Basic counter | Real IMAP, every reply logged |
| Inbox health score | Not included | Live rolling daily score |
| Spam-rescue proof | Not measured | Every spam-save counted |
| Runs beside active campaigns | Risky — shared queue | Fully isolated pipeline |
| Credential security | Varies | AES-256 + live verification |
| Multi-inbox overview | Tab-switching chaos | One unified dashboard |
| Clean pause / resume | Leaves queued ghost sends | Instant stop, zero orphans |
Security + reliability
Infrastructure you can hand to legal, IT, and ops.
We hold inbox credentials — not lightly. Every credential encrypted. Every connection verified. Every pipeline isolated. Built to pass the same checks your enterprise customers will run on you.
Bank-grade encryptionAES-256 on every stored SMTP and IMAP credential — the standard banks use.
Live connection checkEvery inbox tested live before anything saves. Bad credentials never touch our database.
Isolated pipelineWarmup runs on its own infrastructure — zero risk of colliding with active campaigns.
Daily deliverability reportsPer-inbox time-series data — full historical chart of reputation for every account.
Customer love
What 279+ operators say about Sendlio.
"Sendlio is by far the best outreach tool I have ever used. It's reliable, smart, and saves us hours every week."
"Sendlio is by far the best outreach tool I have ever used. It's reliable, smart, and saves us hours every week."
Sofia Lindstrom
Marketing Consultant
"Since integrating Sendlio, our campaigns have become 10× more efficient. It's smooth, powerful, and doesn't require babysitting."
Luca Moretti
Growth Strategist
"Our agency manages 10+ domains. Sendlio keeps them warm and healthy without lifting a finger. Honestly, it's the best tool we didn't know we needed."
Mateo García
Founder, MailForce
"We stopped worrying about domain reputation after switching to Sendlio. It works in the background and keeps our emails out of spam."
Sam Sen
General Manager
"With Sendlio, cold emails finally reach inboxes — no fluff, no spam. Clean, reliable, and ready for serious senders."
Sarah Sen
Operations Lead
"Sendlio's automation takes care of inbox health so we can focus on outreach. Super easy to use and surprisingly powerful under the hood."
John D'Crouze
B2B Growth Advisor
"Every cold emailer should use Sendlio. It protects your domain, boosts deliverability, and gives confidence with every send."
Niko Tanaka
Sales Director
"Sendlio is by far the best outreach tool I have ever used. It's reliable, smart, and saves us hours every week."
Sofia Lindstrom
Marketing Consultant
"Since integrating Sendlio, our campaigns have become 10× more efficient. It's smooth, powerful, and doesn't require babysitting."
Luca Moretti
Growth Strategist
"Our agency manages 10+ domains. Sendlio keeps them warm and healthy without lifting a finger. Honestly, it's the best tool we didn't know we needed."
Mateo García
Founder, MailForce
"We stopped worrying about domain reputation after switching to Sendlio. It works in the background and keeps our emails out of spam."
Sam Sen
General Manager
"With Sendlio, cold emails finally reach inboxes — no fluff, no spam. Clean, reliable, and ready for serious senders."
Sarah Sen
Operations Lead
"Sendlio's automation takes care of inbox health so we can focus on outreach. Super easy to use and surprisingly powerful under the hood."
John D'Crouze
B2B Growth Advisor
"Every cold emailer should use Sendlio. It protects your domain, boosts deliverability, and gives confidence with every send."
Niko Tanaka
Sales Director
"Sendlio is by far the best outreach tool I have ever used. It's reliable, smart, and saves us hours every week."
Sofia Lindstrom
Marketing Consultant
"Since integrating Sendlio, our campaigns have become 10× more efficient. It's smooth, powerful, and doesn't require babysitting."
Luca Moretti
Growth Strategist
"Our agency manages 10+ domains. Sendlio keeps them warm and healthy without lifting a finger. Honestly, it's the best tool we didn't know we needed."
Mateo García
Founder, MailForce
"We stopped worrying about domain reputation after switching to Sendlio. It works in the background and keeps our emails out of spam."
Sam Sen
General Manager
"With Sendlio, cold emails finally reach inboxes — no fluff, no spam. Clean, reliable, and ready for serious senders."
Sarah Sen
Operations Lead
"Sendlio's automation takes care of inbox health so we can focus on outreach. Super easy to use and surprisingly powerful under the hood."
John D'Crouze
B2B Growth Advisor
"Every cold emailer should use Sendlio. It protects your domain, boosts deliverability, and gives confidence with every send."
Niko Tanaka
Sales Director
FAQ
Answers operators ask. In plain English.
No dev jargon. No marketing fog. Real questions with real answers — the same ones we give on sales calls.
What is email warmup — in plain English?
Email warmup is the process of teaching providers like Gmail and Outlook that your inbox is real, active, and trustworthy — before you use it for cold outreach. Sendlio does that by sending natural-looking emails to a private warmup network, getting replies back, and gradually increasing volume day by day. By the time you launch a campaign, your inbox already has a reputation the algorithms recognize.
Does warmup actually improve deliverability?
Yes — and Sendlio shows the proof. Every time a warmup email would have landed in spam but got rescued to inbox, we log it. That rescue is the exact signal Gmail and Outlook use to re-classify a sender as trustworthy. Watch the number climb every day on your dashboard.
How long does warmup take?
For a brand-new domain, 2 to 4 weeks before it is safe to launch a real cold campaign. For a mature inbox that just needs maintenance, the moment warmup is on, it works continuously in the background — no waiting period. Either way, health score starts improving within the first few days.
Can I run warmup while my campaigns are live?
Absolutely. That is the point. Warmup runs on its own isolated pipeline — active campaigns never collide with warmup traffic. Most teams keep warmup on permanently, even on inboxes that are already hitting the primary tab, to maintain reputation over time.
What happens if I turn warmup off?
Clean stop, zero side effects. One toggle off clears every pending job from the queue and pauses the ramp-up cleanly. No ghost emails get sent. Turn it back on later and the system resumes where it left off.
Which email providers does Sendlio warmup support?
Google Workspace (Gmail), Microsoft 365 (Outlook), Zoho Mail, iCloud, Yahoo, and any provider that supports standard SMTP and IMAP. If your inbox can send and receive email, Sendlio can warm it.
Is my email password safe?
Credentials are encrypted at rest with AES-256 — the same standard used by banks and government systems. Before anything is stored, we run a live SMTP and IMAP connection test. Bad credentials are rejected, never saved. Disconnect an inbox at any time and all credentials are purged immediately.
How many inboxes can I warm at once?
No hard limit. Each inbox runs independently with its own starting volume, ramp speed, and sending window. Agencies managing 50+ client inboxes get a single multi-account overview with per-inbox health scores.