How to Improve Email Deliverability for Cold Outreach
If your emails are landing in spam, no script or personalization will save your campaign. Deliverability is the infrastructure beneath every outreach program. This guide covers every layer — from DNS setup to sending behavior — so your emails reach the inbox consistently.
Before you start
- A dedicated sending domain separate from your main company domain
- Access to your domain registrar's DNS settings
- An email sending platform (Instantly, Lemlist, or similar)
Step-by-step guide
Set Up a Dedicated Sending Domain
Never send cold outreach from your primary company domain. Purchase a dedicated sending domain (e.g., tryoutvid.io or get-outvid.com) and configure it exclusively for outbound campaigns. This protects your main domain's reputation from the inevitable spam complaints and unsubscribes that come with cold email.
Register 2-3 sending domains so you can rotate between them and reduce volume per domain. Each domain should forward to your main website so prospects who check the domain see a legitimate business.
Configure SPF, DKIM, and DMARC Records
These three DNS records are non-negotiable for modern inbox placement. SPF declares which servers are allowed to send on behalf of your domain. DKIM adds a cryptographic signature to each email. DMARC tells receiving servers what to do with messages that fail either check. All three must be configured before you warm up or send.
Use a free tool like MXToolbox or mail-tester.com to verify your DNS records are correctly configured. A single misconfigured record can silently tank your deliverability for weeks.
Warm Up Your Sending Domain
A brand-new domain with no sending history looks suspicious to email providers. Use an automated warm-up tool (Instantly Warmup, Lemwarm, or Mailreach) to gradually build a positive sending reputation. Start with 5-10 emails per day and increase by 10-20% each week over 4-6 weeks before sending cold campaigns.
Do not skip the warm-up period even if you're impatient to launch. Sending high volume from a cold domain is one of the fastest ways to get permanently blacklisted.
Respect Sending Volume Limits
Even after warm-up, keep daily sending volume per inbox under 50-80 emails for aggressive campaigns, or 30-50 for more conservative ones. Email providers flag sudden volume spikes as suspicious behavior. Distribute your sends throughout the day using your sending platform's time-delay feature rather than blasting everything at once.
Clean Your Prospect List Before Sending
Sending to invalid email addresses generates hard bounces, which damage your sender reputation quickly. Run every prospect list through an email validation service (NeverBounce, ZeroBounce, or Millionverifier) before importing it into your sending platform. Aim for a bounce rate below 2%.
Re-validate lists that are more than 90 days old. Email addresses churn at roughly 20-30% per year, so a list from last quarter may have a meaningful number of invalid addresses.
Write Plain-Text-Friendly Email Copy
Spam filters penalize emails that look like mass marketing — heavy HTML, multiple links, images, and tracking pixels all increase spam scores. Cold outreach performs best as simple, conversational plain text. Limit yourself to one link (your video or booking link), no unsubscribe images, and no decorative HTML formatting.
Monitor Deliverability Metrics and React Quickly
Track your open rate (a proxy for inbox placement), bounce rate, and spam complaint rate weekly. If open rates drop below 30% or bounce rates rise above 3%, pause sending immediately and investigate. Most deliverability problems are solvable early but become permanent reputation damage if ignored.
Set up Google Postmaster Tools and Microsoft SNDS for your sending domains. These free tools give you direct visibility into how Google and Microsoft rate your sender reputation.
Common mistakes to avoid
Sending cold outreach from your primary company domain
Fix: Immediately set up a dedicated sending domain. Your main domain's reputation affects your entire company's email deliverability, including transactional emails and customer communications — protect it at all costs.
Skipping or rushing the domain warm-up period
Fix: Commit to a full 4-6 week warm-up before sending cold campaigns from a new domain. Use an automated warm-up tool and do not manually send mass emails during this period.
Including multiple links, images, or heavy HTML in cold emails
Fix: Strip your cold email template down to plain text with a single link. Save rich formatting and HTML for nurture campaigns sent to opted-in subscribers who already know you.
What are the key takeaways from this guide?
- Deliverability is infrastructure — invest in domain setup, DNS records, and warm-up before you write a single line of copy, because none of your messaging matters if emails don't reach the inbox.
- Protecting your primary domain by using dedicated sending domains is the single most important deliverability decision you will make.
- Monitor bounce rate and open rate weekly; deliverability problems that are caught early are almost always fixable, while problems that are ignored can result in permanent blacklisting.
Frequently asked questions
How long does it take to warm up a new sending domain?
A thorough warm-up takes 4-6 weeks using an automated tool. Rushed warm-ups over 1-2 weeks are better than nothing but still leave your domain more vulnerable to reputation damage from spam complaints or bounces. The investment in a proper warm-up pays dividends for the life of the domain.
Does including a video link in my email hurt deliverability?
A single link in an otherwise plain-text email is fine. The key is to use a clean, branded short URL rather than a raw video hosting link with tracking parameters. Outvid provides clean thumbnail links specifically designed for email embedding without triggering spam filters.
What bounce rate is acceptable for cold email?
Keep hard bounces below 2% and aim for under 1% if possible. Most sending platforms will automatically pause your account if you exceed 5% — at that threshold, significant reputation damage has already occurred.
Should I use a custom tracking domain for click tracking?
Yes, if your sending platform supports it. A custom tracking domain (e.g., track.yoursendingdomain.com) prevents your clicks from being processed through a shared tracking domain that may be on spam blacklists due to other users' behavior.
How do I recover a domain that's been blacklisted?
First, identify which blacklist(s) the domain appears on using MXToolbox. Most blacklists have a delisting request process. Then address the root cause — remove bad addresses, reduce volume, and improve your warm-up score. Recovery typically takes 2-4 weeks but depends on the blacklist provider.
Related resources
Pair Great Deliverability With AI-Personalized Video
Once your sending infrastructure is solid, Outvid helps you fill every email with a personalized AI video that gets prospects to reply.