The short answer
For cold email to reach the inbox, send from separate domains and inboxes, set up SPF, DKIM and DMARC correctly, warm up new inboxes gradually, keep volumes modest, use clean and verified lists, include an easy way to opt out, and write short relevant messages. Skipping these steps is the fastest way to land in spam.
Key takeaways
- Protect your main domain by sending from separate ones.
- SPF, DKIM and DMARC are expected by major inbox providers.
- Warm up new inboxes and increase volume slowly.
- Verified lists and relevant messages keep complaints low.
- Always include a physical address and a way to opt out.
Why use separate sending domains?
Cold outreach carries some risk of spam complaints. Using separate domains, similar to your brand, protects your main business email so day-to-day messages are unaffected if a sending domain gets flagged.
What are SPF, DKIM and DMARC?
They are DNS records that prove your emails are really from you. SPF lists which servers may send for your domain, DKIM signs messages, and DMARC tells providers what to do when checks fail. Major providers now expect all three, especially from bulk senders.
How should you warm up an inbox?
Start with a small number of emails per day and increase gradually over several weeks, mixing in normal conversations. Sending large volumes from a brand new domain looks suspicious and often ends in the spam folder.
How do you keep complaints low?
- Verify email addresses before sending.
- Target a defined, relevant audience.
- Keep messages short and honest.
- Include your name, company and a physical address.
- Honor opt-outs quickly.
- Stop following up after a clear no.
What should you monitor?
Watch bounce rates, spam complaints and replies. If bounces or complaints rise, pause and fix your list or message before continuing. Consistent monitoring protects your reputation over time.
Frequently asked questions
Is cold email legal?
In the US, B2B cold email is generally allowed under CAN-SPAM if you identify yourself, include a physical address, avoid deception and honor opt-outs. Other regions have stricter rules. This is general information, not legal advice.
How many emails should I send per day?
Start small on a new inbox and increase gradually. Quality and relevance matter more than volume.
Why do my cold emails go to spam?
Common causes are missing authentication, a new or unwarmed domain, poor lists, spammy wording or too much volume too fast.