New mailboxes have no history
Inbox providers judge a sender by its track record. A brand new mailbox has none, so the first big send is the one that gets filtered.
Email warm-up
Email warm-up that runs for 21 days while you build.
A new mailbox that sends hard on day one looks like a spammer. FirstSales warms every mailbox you connect, slowly, for 21 days in three phases, so inbox providers learn to trust it before your real campaigns go out. You turn it on once. It does the waiting for you.
$1 for 3 days · Cancel anytime · No contract
- 01
21-day warm-up in three phases
- 02
Runs in the background from day one
- 03
Unlimited mailboxes, each one warmed
- 04
Included on every plan, from $29/mo
The problem
A cold inbox is a filtered inbox.
Gmail and Outlook do not know you yet. Until they do, they treat every email from a new mailbox with suspicion, and they are quick to send it to spam.
Going fast looks like spam
Real people do not go from zero to hundreds of emails in a day. When a mailbox does, providers notice, and the damage can follow the domain for weeks.
Warming by hand never gets done
Sending a few emails a day to friends and asking them to reply is slow, boring and easy to forget. Most people skip it, then wonder where the replies went.
The 21-day track
Three phases, then it keeps going.
Warm-up is not a switch you flip on the day you send. It is a slow climb that starts the moment you connect, and it never really stops. Here is what happens in each phase, and what is left for you to do.
01Days 1–7
Small and steady
Low daily volume
- FirstSales
- Sends a few AI-written conversations a day with the warm-up network. They get opened, answered and pulled out of spam.
- You
- Connect the mailbox, fix any red SPF, DKIM or DMARC check, and start building your first campaign.
02Days 8–14
Growing
Volume rises
- FirstSales
- Auto-adjust raises the daily limit each night, based on how yesterday's sending went.
- You
- Write or review your sequence, add your lead list and read the drafts. Nothing has to wait.
03Days 15–21
Full speed
Full sending volume
- FirstSales
- Brings the mailbox up to full volume on a domain that inbox providers have learned to trust.
- You
- Check the Warmup score and the Daily Breakdown, then point real campaigns at the mailbox.
04Day 22 onward
Keep it running
Warm-up stays on
- FirstSales
- Keeps warm-up traffic flowing next to your real sends, so quiet days never let your reputation slip.
- You
- Send your campaigns. Add more mailboxes when you need more volume.
How it works
Three steps, and only the first one is yours.
Warm-up is a single switch on each mailbox. After that it runs on its own, every day, for as long as you send.
- 01
Connect your mailbox
Add Gmail, Outlook or any SMTP inbox. SPF, DKIM and DMARC are checked as you connect, with the exact record to add if one is missing.
- 02
Turn warm-up on
Open the Warm Up tab and switch it on. Small AI-written conversations start the same day and grow over 21 days.
- 03
Build while it ramps
Make your campaign, add leads and read drafts. When the Warmup score looks healthy, send for real. Warm-up keeps running next to you.
What you get
Trust you earn slowly, without doing the slow part.
Everything a careful sender would do by hand, done for every mailbox, every day. Included on every plan.
Start building on day one
Warm-up runs in the background from the minute you switch it on. You build campaigns and read drafts while the mailbox earns trust.
No volume to guess
Auto-adjust sets each day's sending limit overnight, from how yesterday's sending went. You never pick a number and hope.
Real conversations, not noise
Warm-up messages are AI-written, then opened, answered and rescued from spam. Those are the signals providers use to trust a sender.
Progress you can see
The Warmup score, Days Active and a Daily Breakdown show what happened each day. No guessing whether it works.
Every mailbox, warmed
Unlimited mailboxes on every plan, and each one warms on its own schedule. Add ten and all ten ramp at once.
It never switches off
Warm-up keeps running after you go live, so a slow week of sending never lets the trust you built fade away.
Four parts of warm-upyou never have to manage
The ramp, the conversations, the daily limit and the checks. Each one runs for every mailbox you connect.
- The ramp
21 days from a new mailbox to full volume
Warm-up starts small and grows as inbox providers learn to trust the mailbox. Three phases, one after the other, without you touching a setting.
- Days 1–7: small and steady. Low daily volume to earn first trust with inbox providers.
- Days 8–14: growing. Volume rises as your sender score improves.
- Days 15–21: full speed. Full sending volume on a domain inbox providers trust.
- The conversations
Messages that act like real email
Warm-up sends short AI-written conversations between your mailbox and the warm-up network. They get the treatment real, wanted email gets.
- Opened and read. Each message is opened, like email someone was waiting for.
- Answered. Replies show your mailbox takes part in real conversations.
- Pulled out of spam. Messages that land in spam are moved back to the inbox.
- The daily limit
Auto-adjust sets the pace every night
You do not set warm-up volume by hand. Each night, Auto-adjust reads how yesterday went and sets today's limit, climbing only as fast as the mailbox can take.
- Based on yesterday. Each day's limit comes from the sending health of the day before.
- A ceiling if you want one. Set a send ceiling for a hard cap, or leave it blank for none.
- No knobs to tune. The defaults do the work, so there is nothing to get wrong.
- The checks
Warm-up plus the safety net around it
Warm-up builds trust. The checks around it protect that trust once you send real campaigns, so one bad list does not undo three weeks of work.
- Authentication checked. SPF, DKIM and DMARC, with the exact record to add.
- Contacts checked before each send. Bad addresses are left out before they can bounce.
- Health watched every hour. A health grade per inbox, from its bounce rate and warm-up score.
- Sending rotates. If one mailbox has trouble, your others carry the campaign.
What warm-up actually does
One conversation, five signals inbox providers trust.
Every warm-up message is a short conversation between your mailbox and the warm-up network. Each step sends a signal that a real person would send. You never write or manage any of it.
- 01 · Sent
Your mailbox sends a short, AI-written message, at a pace Auto-adjust sets for the day.
- 02 · Delivered
The message reaches a real mailbox in the warm-up network.
- 03 · Opened
It gets opened and read, the way a person reads email they wanted.
- 04 · Replied
It gets a reply, so your mailbox shows real two-way conversations.
- 05 · Rescued
If it landed in spam, it is pulled back out to the inbox. That tells the provider it made a mistake.
Each of these lands in the Daily Breakdown on the Warm Up tab, one row per day, so you can see the loop working.
Plain guide
Email warm-up, explained without jargon.
What warm-up is, why it works, and the mistakes that undo it. General truths, no magic numbers.
- 01
What email warm-up is
Warm-up is the slow start every new mailbox needs. Instead of sending a full campaign on day one, the mailbox sends a little email each day, gets real engagement on it, and sends a little more as trust builds. Inbox providers watch that history. A mailbox with a steady, healthy record gets the benefit of the doubt. A mailbox with no record, or a sudden spike, gets filtered.
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Why a new domain starts at zero
Buying a new domain for cold email is common and sensible: it keeps your main domain safe. But a new domain is a stranger to Gmail and Outlook. It has sent nothing, been replied to by nobody and been marked as safe by no one. Warm-up gives it that missing history before you ask it to carry real campaigns.
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Why slow beats fast
Providers look at how your sending changes over time. A smooth climb looks like a real person whose business is growing. A jump from nothing to a full campaign looks like someone who bought a domain to blast a list. That is why FirstSales warm-up runs for 21 days in three phases, and why Auto-adjust only raises the limit when yesterday went well.
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Why engagement matters more than volume
Sending email is easy. Getting it opened, answered and moved out of spam is what proves it was wanted. Warm-up conversations do all three, so your mailbox builds the kind of record that real, welcome email builds. Volume alone, without engagement, teaches providers nothing good about you.
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Why authentication comes first
SPF, DKIM and DMARC are the records that prove an email really came from your domain. If one of them fails, warm-up has a ceiling it cannot climb past, however long it runs. Fix the records first. FirstSales checks them when you connect a mailbox and shows the exact record to add.
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Why you never switch warm-up off
Trust is not a box you tick once. On quiet weeks, when you send little real email, warm-up keeps a steady stream of good signals flowing. Turning it off and on again does not speed anything up. It pauses the progress you made. Leave it running next to your campaigns for as long as the mailbox sends.
- 07
What warm-up cannot fix
Warm-up builds trust. It cannot make a bought list clean, a generic email welcome or a burned domain new. If you send to dead addresses or to people who never asked to hear from anyone like you, providers will notice whatever your warm-up score says. That is why warm-up in FirstSales sits next to contact checks, health grades and short, personal emails.
Read the Warm Up tab
Every status, in plain words.
The Warm Up tab tells you where each mailbox stands. Most of the time the answer is to wait. When it is not, the tab tells you why.
What it meansWhat to do
- Ramping up — Day N
What it means: Warm-up is climbing, day by day. This is normal for a new mailbox.
What to do: Nothing. Keep building your campaign and let it run.
- Placement pending
What it means: The mailbox is waiting for placement data before it can be scored.
What to do: Nothing. It clears on its own as data comes in.
- Healthy
What it means: The mailbox is warm and sending well.
What to do: Point campaigns at it. Leave warm-up on.
- Maintenance mode
What it means: The ramp is done. The score levels off by design.
What to do: Nothing. This is the finished state, not a stall.
- Paused or Blocked
What it means: Warm-up is not moving. A banner names the reason.
What to do: Read the reason. Usually: reconnect the mailbox or fix a DNS record.
- Verify this connector
What it means: The mailbox is not verified yet, so warm-up cannot start.
What to do: Finish connecting the mailbox. The warm-up switch unlocks after that.
Before you send
A warm-up checklist for every new mailbox
Run through this the day you connect a new mailbox, and again before its first real campaign.
- The mailbox is on the domain you will really send from
- SPF, DKIM and DMARC all pass for that domain
- The mailbox is connected and verified
- Warm-up is switched on in the Warm Up tab
- Auto-adjust is on, with a send ceiling only if you need one
- You leave warm-up running for the full 21 days
- You check the Daily Breakdown every few days
- Any Paused or Blocked reason is fixed the day it shows
- Your first campaign starts at a modest pace
- Warm-up stays on after the campaign goes live
“User Interface, Ease of Use, Able to hit the inbox in the first attempt.”
Sadashiv B.Founder, small business · G2Before and after
Warming a mailbox, by hand and with FirstSales
Same goal, very different weeks.
By hand
The way most people try it once.
- You email friends and colleaguesAnd ask them to reply, every day, for weeks.
- You guess the daily volumeToo low wastes time. Too high gets you filtered.
- Spam goes uncheckedNobody pulls your messages back out of spam.
- You forget a few daysLife happens, and the ramp stalls.
- You stop once you go liveThen trust fades on quiet weeks.
- One mailbox at a timeWarming five by hand is five times the chore.
With FirstSales
One switch per mailbox.
- The warm-up network repliesAI-written conversations, opened and answered.
- Auto-adjust sets the paceEach night, from how yesterday went.
- Spam is rescuedMessages that land in spam are moved back.
- It runs every day21 days in three phases, no reminders needed.
- It keeps going after launchWarm-up runs next to your real campaigns.
- Every mailbox at onceUnlimited mailboxes, each one warmed.
Why teams switch
Email warm-up: FirstSales vs a typical tool
Many teams pay for warm-up in one tool and send from another. FirstSales does both in one place.
| What you get | Typical tool | FirstSales |
|---|---|---|
| 21-day warm-up | Varies | Included, three phases |
| Daily volume | Varies | Set nightly by Auto-adjust |
| Rescue from spam | Varies | Included |
| Day-by-day breakdown | Varies | On the Warm Up tab |
| Runs after launch | Varies | Next to real campaigns |
| Mailboxes | Varies | Unlimited, each one warmed |
| Health grade per inbox | Varies | Checked every hour |
| Price | Varies | $29/mo, warm-up included |
| Start your $1 trial | ||
What people say
From people who use it
Real words from real users. No paid reviews.
“If you are looking to fix your sales pipeline, you should definitely try [it]. My open rate has increased drastically. The UI and UX are easy to understand, even for a beginner like me.”
Pooja Dhole
@ThisIsPoojaD
“One of the best email outreach tools I have ever seen in my 9 years of business experience. It has solved the problem of email outreach for my cold emails.”
Santhosh K.
Founder and CEO, small business
“I have always struggled in cold outreach. However, Firstsales has provided an excellent tool for cold outreach.”
Kaushal S.
Founder, small business
Questions,answered plainly.
Can’t find yours? Write to us.
01What is email warm-up?
It is a slow start for a new mailbox. The mailbox sends a little email each day, gets it opened and answered, and sends more as inbox providers learn to trust it. FirstSales does this for 21 days in three phases.
02How long does warm-up take in FirstSales?
21 days to full volume, in three phases: small and steady, growing, then full speed. You can build campaigns and read drafts from day one while it runs.
03Do I have to set the daily volume?
No. Auto-adjust sets each day's limit overnight from how yesterday's sending went. If you want a hard cap, you can set a send ceiling. Otherwise leave it blank.
04Should I keep warm-up on after my campaigns start?
Yes. Warm-up runs next to your real campaigns and keeps good signals flowing on quiet days. Turning it off and on again pauses your progress instead of speeding it up.
05Can I warm up more than one mailbox?
Yes. Every plan includes unlimited mailboxes, and each one warms on its own schedule. Switch warm-up on for each mailbox you connect.
06My warm-up will not start. Why?
Usually the mailbox is not verified yet. The Warm Up tab says so. Finish connecting it and the switch unlocks. If it says Paused or Blocked, read the reason: reconnecting the mailbox or fixing a DNS record clears most of them.
07Can warm-up promise my emails reach the inbox?
No, and nobody honestly can. Warm-up builds trust. Clean lists, working SPF, DKIM and DMARC, and short personal emails keep it. FirstSales helps with all of them and shows you the numbers.
08Does warm-up cost extra?
No. Warm-up is included on every plan, from $29/mo, with unlimited mailboxes. Try it for $1 for 3 days and cancel any time from your dashboard.
Outreach that keeps going after you log off.Leads, emails, follow-ups and replies, handled.
Connect unlimited mailboxes and let AI agents find leads, write each email and follow up. Or send your own templates in manual mode. From $29/mo.
$1 for 3 days · Cancel anytime · No contract