Short answer: Good deliverability starts before you write a single email. Use a dedicated sending domain or subdomain, set up SPF, DKIM and DMARC, warm up new mailboxes gradually, send only to verified contacts, keep daily volume per mailbox modest, write plain and relevant emails, and make opting out easy. Mailbox providers such as Google and Yahoo have tightened requirements for senders in recent years, so authentication and low complaint rates matter more than ever. Monitor bounces, replies and spam complaints, and fix problems quickly.
Why deliverability matters
If your emails land in spam, nothing else matters: copy, offer and targeting are wasted. Poor deliverability also hurts your main domain, which can affect sales, support and billing emails. For US and Canadian outbound teams, protecting sender reputation is a core part of the job.
Step 1: Choose your sending domains
Many teams send cold outreach from a separate domain or subdomain rather than their primary company domain. This helps isolate risk. If you do this:
- Use a domain that clearly relates to your brand
- Set up a simple website or redirect so the domain looks legitimate
- Keep the sender name and signature consistent with your company
Step 2: Authenticate with SPF, DKIM and DMARC
- SPF lists which servers can send email for your domain
- DKIM adds a cryptographic signature that proves the message was not altered
- DMARC tells receivers what to do if SPF or DKIM fail, and provides reports
Set these up in your DNS following your email provider's documentation. Start DMARC with a monitoring policy, review reports, then tighten over time. Google and Yahoo have published sender requirements that include authentication, easy unsubscribe for bulk senders and low spam complaint rates. Review their current guidelines directly.
Step 3: Warm up new mailboxes
New domains and mailboxes have no reputation. Start with low daily volume and increase gradually over several weeks. Early sends should go to contacts likely to engage. Avoid sudden spikes, which can look like spam behavior.
Step 4: Send only to verified contacts
Bounces damage reputation. Before each campaign:
- Verify emails with a verification tool
- Remove role-based addresses unless they are appropriate for your offer
- Pilot-send a small batch and check bounce rates
- Remove hard bounces immediately
Lists built from multiple sources should be deduplicated and checked for record age.
Step 5: Keep volume sensible
Spread sending across several mailboxes rather than pushing one mailbox hard. Keep per-mailbox daily volume modest and consistent. Your email provider and sending tool may have their own limits, so check them.
Step 6: Write emails that look like real emails
- Keep the first email short and personal
- Avoid heavy images, attachments and many links
- Avoid tracking links in early emails if they hurt deliverability for you
- Do not use misleading subject lines
- Personalize based on real context about the person or company
Step 7: Make opting out easy
Include a clear way to opt out and honor it quickly across every tool. CAN-SPAM requires a working opt-out mechanism and a physical postal address for commercial email. For Canadian recipients, CASL generally requires consent and clear identification. Low complaint rates protect your reputation.
Step 8: Monitor and respond
Track:
| Metric | What it tells you |
|---|---|
| Bounce rate | List quality |
| Reply rate | Relevance and inbox placement |
| Spam complaints | Targeting and messaging problems |
| Open rates (with caution) | Directional only, as privacy features affect tracking |
Use tools such as Google Postmaster Tools to monitor domain reputation if you send enough volume to Gmail users. If metrics drop, pause, investigate and fix list quality or messaging before resuming.
Common mistakes
- Sending cold email from your main company domain at high volume
- Skipping SPF, DKIM or DMARC
- Sending large volumes from new mailboxes on day one
- Using unverified or old lists
- Ignoring spam complaints and opt-outs
Compliance (high level)
Follow CAN-SPAM for US commercial email: accurate headers, honest subject lines, a physical address and a working opt-out. If you email Canadian prospects, follow CASL. Applicable state privacy laws may also apply. Deliverability and compliance go together: respectful, relevant email is both.
Where PeakAI fits
PeakAI is a contact finder with a Chrome extension that finds phone numbers, work emails and personal emails from professional profiles, drawing on global sources, with bulk export and integrations. Accurate contact data supports deliverability by reducing bounces. Use PeakAI or another tested finder to locate contacts, then run your own verification and pilot sends before scaling. Phone numbers can also help you reach prospects without relying on email alone. Check thepeakai.com for current features, coverage and pricing.
FAQ
Should I send cold email from my main domain?
Many teams use a separate domain or subdomain to protect their primary domain's reputation. Whatever you choose, authenticate it properly.
How long should I warm up a new mailbox?
Typically several weeks of gradually increasing volume. Follow guidance from your email provider and sending tool.
Do I need DMARC for cold outreach?
It is strongly recommended, and major mailbox providers expect authentication from senders. Start with monitoring, then tighten.
Why are my cold emails going to spam?
Common causes include missing authentication, high bounce rates, sudden volume spikes, spammy content and spam complaints.
Are open rates reliable for measuring deliverability?
Not fully, since privacy features can distort them. Use bounces, replies and complaints alongside opens.