Skip to content
NewSee how

How to Set Up Email Warm-up in FirstSales

Turn on AI warm-up for a new mailbox so your cold-email domain builds sender reputation before you send real campaigns.

Tutorials
Email Warm-up
min read
8 min
steps
7 · Beginner

  1. Connect the mailbox you'll warm up

    Warm-up runs on a real mailbox, so connect it first. Open Connectors from the left nav and click Add Connector. Google Workspace and Microsoft 365 connect with one OAuth click; any other provider connects over SMTP/IMAP with your host, port, and app password.

    Use the domain you actually plan to send cold email from. Warming a throwaway address builds reputation you'll never use.

    Connect the mailbox you'll warm up

  2. Confirm SPF, DKIM, and DMARC are passing

    Authentication is what tells inbox providers your mail is really from you. Open the connector and check the Email Authentication panel on the Details tab (FirstSales scores your domain and marks SPF, DKIM, and DMARC with a red ✗ if they're failing. Anything red caps your warm-up before it starts.

    • SPF) one v=spf1 record that includes your sending provider.
    • DKIM (the signing key your provider gives you, published as a TXT record.
    • DMARC) start at p=none so you collect reports without blocking mail.

    Click Set Up DNS Records for the exact records to add at your DNS host, then re-run the check until the score reaches 100%.

    Confirm SPF, DKIM, and DMARC are passing

  3. Turn on AI warm-up

    Open the connector's Warm Up tab and switch Email Warmup on. FirstSales begins sending small volumes of AI-generated conversation between our warm-up network and your inbox. Those messages get opened, replied to, and Spam Rescued (pulled back out of the spam folder) (the exact signals providers use to trust a new sender.

    This runs quietly in the background. You don't write or manage any of it) the Warmup score, Days Active, and a 7-day breakdown track it for you.

  4. Let auto-adjust manage the ramp

    You don't set warm-up volume by hand. On the Details tab under Sending Configuration, leave Auto-adjust on: it sets each day's sending limit nightly based on yesterday's sending health, climbing as your reputation builds.

    Set a Send ceiling only if you want a hard cap; leave it blank for none. The Daily Target on the Warm Up tab shows today's warm-up volume so you can see the ramp working.

  5. Give the domain time to build reputation

    Reputation is earned over days, not minutes. Let warm-up run for at least 2 weeks before you point real campaigns at the mailbox; 3–4 weeks is safer for a domain with no history.

    Keep warm-up running after you go live too. It keeps a baseline of positive engagement flowing even on days you send fewer real emails.

  6. Watch the warm-up metrics

    Track progress on the connector, not a guess. Two places tell you how it's trending:

    • Warmup score (Warm Up tab): moves from Placement pending to a placement rating as data comes in.
    • Sending health (Details tab): scored nightly from yesterday's metrics. Keep it climbing toward Healthy.

    The Daily Breakdown table shows Sent, Delivered, Replied, Bounced, and Spam Rescued per day. If health stalls or bounces climb, it's almost always authentication or ramping too fast: revisit steps 2 and 4 before sending real volume.

  7. Launch your first campaign on the warmed mailbox

    Once the Warmup score is healthy and you've cleared the 2-week minimum, the connector is ready. When you build a campaign, select this connector as a sender. FirstSales runs your free list cleaning first so no bounce hits your freshly-built reputation, then blends real sends with continued warm-up traffic.

    Start real campaigns at modest daily volume and let them ramp alongside warm-up rather than replacing it overnight.

Pro tips

  • Warm the domain you'll actually send from

    Reputation is tied to the sending domain. Warming a throwaway address builds trust you'll never spend: connect the real mailbox from day one.

  • Get authentication to 100% before you ramp

    A red SPF, DKIM, or DMARC caps warm-up before it starts. Fixing the DNS records is the single biggest lever on how fast reputation climbs.

  • Never switch warm-up off after launch

    Keep it running alongside live campaigns. It keeps a baseline of opens and replies flowing on days you send little real mail, so reputation never sags.

  • Let auto-adjust set the pace

    Don't hand-tune daily volume. Auto-adjust reads yesterday's sending health each night and ramps only as fast as your inbox placement allows.

Frequently asked questions

How long should I warm up before sending real campaigns?

At least 2 weeks for a mailbox on a domain with some history, and 3–4 weeks for a brand-new domain with none. Watch the Warmup score and Sending health rather than the calendar: launch when they're trending Healthy, not just when time is up.

Do I have to write the warm-up emails myself?

No. FirstSales generates the conversation with AI and our warm-up network opens, replies, and Spam Rescues them automatically. You turn the toggle on once and it runs quietly in the background: there's nothing to write or manage.

Can I warm up more than one mailbox at a time?

Yes. Each connector warms independently, so connect as many mailboxes as your plan allows and toggle warm-up on for each. Reputation is built per-domain, so warming several inboxes on the same domain compounds nicely.

Will warm-up fix a domain that's already flagged as spam?

It helps rebuild trust, but it isn't magic. If a domain is already burned, fix SPF, DKIM, and DMARC first, ramp slowly, and give it several weeks. A severely damaged domain is sometimes best retired in favour of a fresh sending domain.

What happens if SPF, DKIM, or DMARC show a red ✗?

Anything red caps your warm-up before it can build momentum. Open the connector's Details tab, click Set Up DNS Records, add the records at your DNS host, then re-run the check until the score reaches 100% before you rely on the mailbox.

How much daily volume does warm-up send?

You don't set it by hand. Auto-adjust calculates each day's limit nightly from yesterday's sending health, climbing as reputation builds. Set a Send ceiling only if you want a hard cap; leave it blank for none.

Should I keep warm-up running after I go live?

Yes: leave it on. It keeps a steady stream of positive engagement flowing even on low-send days, which protects the reputation you spent weeks building. Real campaigns and warm-up traffic are designed to run side by side.

How do I know warm-up is actually working?

Three signals on the connector: the Warmup score moves from Placement pending to a placement rating, Sending health trends toward Healthy, and the Daily Breakdown table shows Sent, Delivered, Replied, Bounced, and Spam Rescued per day. Stalling health or rising bounces almost always trace back to authentication or ramping too fast.

Email Warm-up

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.

Start your $1 trial See pricing

$1 for 3 days · Cancel anytime · No contract

Install with AI

Your coding agent sets up the FirstSales CLI and skills for you.

Prompt for Claude Code

I'm setting up FirstSales (https://firstsales.io), an AI outbound sales platform: campaigns, contacts, a reply inbox, deliverability and lead signals. Help me get my workspace sending real, good emails end to end, from Claude Code.

Read these first so you know how FirstSales works:
- Developer docs and API: https://developer.firstsales.io
- CLI: https://www.npmjs.com/package/@firstsales.io/cli
- Skills for coding agents: https://github.com/firstsalesio/firstsales-skills (read README.md and GUIDE.md)

Setup
1. Install the CLI: npm install -g @firstsales.io/cli
2. Install the FirstSales skills:
   claude plugin marketplace add firstsalesio/firstsales-skills
   claude plugin install firstsales@firstsales
3. Ask me if I already have a FirstSales account. If not, send me to https://app.firstsales.io to sign up.
4. Ask me to create an API key under Settings → API → API Keys, with only the scopes we need.
   Never ask me to paste the key into this chat. Tell me to run this in my own terminal, so the key stays hidden:
   read -rs FS_KEY && firstsales auth login --api-key "$FS_KEY"; unset FS_KEY
5. Run `firstsales whoami` and tell me which workspace and organisation we are connected to.

Then ask me about my business: what I sell, who I sell to (roles, company size, countries), my best customers, and what I use today for outbound (tools, lists, mailboxes). Walk me through:
1. Teaching FirstSales my business: website, offer, proof points and case studies in the knowledge base, so the AI writes like someone who knows the product.
2. Connecting my sending mailboxes and checking my sending domain: SPF, DKIM, DMARC and warm-up. If anything is unhealthy, tell me the exact DNS record to add.
3. Bringing in contacts: import my CSV or CRM export into a clean list, remove duplicates and bad emails, and block domains I must never email (customers, competitors, my own).
4. Building my first campaign: the right list, senders, steps and timing. Write the sequence with me, show me the drafts, and do not launch until I say yes.
5. Setting up Signals if it fits: find people engaging with LinkedIn posts about topics my buyers care about, and turn them into leads.
6. Inviting my team and giving each person the right access.

Once campaigns run, show me how to work the reply inbox from here: which replies need an answer, draft responses in my voice, and move good conversations into deals. If I use Cal.com, connect it so follow-ups can offer my booking link (not the first email).

Throughout, as you learn about my business, proactively suggest and help create:
- Reply templates for the questions and objections my prospects are likely to raise, based on my product, site and codebase if you can see them.
- Campaign ideas and segments worth testing, with the reason for each.

Safety rules:
- Show every change as a dry run (--dry-run) first and wait for my yes. Never send emails, launch campaigns or delete anything without my yes.
- Tell me before anything that spends credits, and how many.

Be opinionated. If the docs give a sensible default, just use it. Don't make me choose between five options.
Developer docs ↗npm: @firstsales.io/cli ↗GitHub: firstsales-skills ↗