Sending cold email from a new domain? Without 2 weeks of warm-up, your emails land in spam. Here's the exact ramp schedule SDR teams use.
Quick answer
To warm up a cold email domain for outbound: (1) buy a secondary domain similar to your primary (e.g. get-scrupp.com for scrupp.com), (2) set up SPF, DKIM, and DMARC DNS records, (3) create 3-5 mailboxes on the domain (sdr1@, sdr2@, etc.), (4) run an email warm-up tool (Instantly, Mailwarm, Warmbox) for 14 days at 20-50 emails/day, (5) after day 14, ramp cold sends to 50/day, then 100/day by day 21. Total warm-up period: 2-3 weeks. Never cold-email from your primary domain — if you get flagged, your main domain reputation suffers permanently.
Step by step
6 steps — about 10-15 minutes end-to-end.
Never cold-email from your primary domain (scrupp.com). Buy a similar secondary domain (get-scrupp.com, try-scrupp.com, scrupp.io). Cost: $10-15/year. Register via Google Domains, Namecheap, or Cloudflare. This protects your main domain's sender reputation.
DNS records that prove you're authorized to send email from this domain. SPF: tells mail servers which IPs can send for your domain. DKIM: cryptographic signature proving the email wasn't tampered with. DMARC: policy telling receivers what to do with unauthenticated emails. All three are required — missing any one drops deliverability by 10-30%.
Create individual mailboxes (sdr1@get-scrupp.com, sarah@get-scrupp.com). Don't use generic addresses (info@, sales@). Each mailbox should have a real-looking signature with name, title, company, and phone. Google Workspace ($6/user/month) or Zoho Mail ($1/user/month) are the most common providers.
Use a warm-up tool (Instantly, Mailwarm, Warmbox) that automatically sends and receives emails between your new mailboxes and a network of warm-up accounts. This builds sending reputation with Gmail and Outlook. Start at 20 emails/day, ramp to 50/day by day 7. Keep warm-up running continuously even after you start cold sends.
After 14 days of warm-up, start sending real cold emails. Day 14-21: 50 sends/day per mailbox. Day 21-28: ramp to 100/day. Day 28+: max 150/day per mailbox. 3 mailboxes × 100 sends = 300 cold emails per day sustainably.
Track: open rate (should be 30-50%), bounce rate (under 3%), spam complaint rate (under 0.1%). If open rate drops below 20%, pause sends for 48 hours and investigate. Use Mail-Tester.com to check your spam score before launching.
Pro tips
Never skip warm-up. Sending 100 cold emails from a brand-new domain on day 1 = instant spam folder. The domain has zero reputation, and ISPs assume it's a spammer. 14 days of warm-up is the minimum.
Keep warm-up running forever. Even after you start cold sends, keep the warm-up tool active. It maintains positive engagement signals (opens, replies) that counterbalance cold email metrics.
3 mailboxes is the sweet spot. One mailbox at 100/day is risky. Three mailboxes at 100/day each gives you 300 sends/day with lower per-mailbox risk. Adding more (5-10) is fine for scale.
Plain text emails deliver better than HTML. No images, no tracking pixels, no HTML formatting. Gmail favors plain-text person-to-person emails over marketing-style HTML. Your cold email should look like a human wrote it in Gmail, not Mailchimp.
Verified email lists protect your domain. The #1 threat to sender reputation is bounces. Use email verification to confirm every address before sending. Target under 3% bounce rate.
FAQ
14 days minimum for basic warm-up. 21-28 days for optimal reputation building. Some SDR teams warm up for 30 days before any cold sends — it's slower to start but results in better long-term deliverability.
SPF (Sender Policy Framework): DNS TXT record listing authorized sending IPs. DKIM (DomainKeys Identified Mail): cryptographic signature added to each email header. DMARC (Domain-based Message Authentication): policy record telling receivers to reject/quarantine unauthenticated mail. All three work together to prove your emails are legitimate.
If your cold emails get flagged as spam (even once), it damages the domain's sender reputation. This affects ALL email from that domain — including customer emails, transactional emails, and marketing emails. Using a secondary domain isolates the risk.
Per mailbox: 100-150/day is the safe ceiling for sustained cold emailing. Per domain (all mailboxes combined): 300-500/day. Above this, you need multiple secondary domains to spread the volume. Never send 1,000+ emails/day from a single domain.
Instantly ($37/month, includes warm-up + sequencer), Mailwarm ($69/month, warm-up only), Warmbox ($15/month, warm-up only). Instantly is the best value if you also need a cold email sequencer. All three connect to Google Workspace and Outlook.
Under 3% is ideal. 3-5% is tolerable. Above 5% damages your domain reputation and triggers spam filters. The solution: verify every email before loading into your sequence.
You can warm up Gmail/Google Workspace mailboxes (most common for cold email). You cannot effectively warm up @gmail.com personal addresses for cold outreach — Google monitors and restricts bulk sending from personal accounts.
If your domain lands on a blacklist (Spamhaus, Barracuda), remove it by: (1) stopping all cold sends, (2) running warm-up only for 7-14 days, (3) submitting a delisting request to the blacklist provider. Prevention is easier — verify emails, pace sends, and monitor daily.
Free Chrome extension. Pay-as-you-go: 1 credit per scraped lead, 1 credit per verified email or phone. No credit card to start.