Cold email outreach remains one of the most effective ways to start conversations with potential customers. Yet even the strongest message will fail if it never reaches the inbox. Modern email providers like Gmail and Outlook use strict filtering systems, especially when messages are sent to people who have not engaged with your brand before. That means your technical setup has a direct impact on whether your campaigns succeed or disappear into spam.
In this article, we walk through the essential steps every company should take before launching cold email campaigns. You will learn how to protect your main domain, how to authenticate your emails, how to warm up new mailboxes, and how to test deliverability. This is the same process we follow internally and with clients to ensure strong results from day one.
Why a proper setup is essential
providers treat these messages with increased caution. Without a solid foundation, several issues can occur.
- Emails may land in spam instead of the inbox.
- Your domain reputation may get damaged, which can influence all future emails from your company.
- Your sending volume may be automatically restricted without warning.
A professional setup prevents these issues and allows you to scale outreach safely. The first step is separating your outreach activity from your main domain.
Use a separate domain or subdomain for outreach
Sending cold emails from your main domain (company.com) is risky. If you run campaigns from that domain and something goes wrong, the reputation of your core brand suffers. That can affect daily communication, including messages to clients and partners.
A safer approach is to use a separate domain or subdomain for outreach, such as:
getcompany.com
trycompany.com
hello.company.com
This setup protects your main brand while giving you room to warm up and scale outreach gradually. The outreach domain functions like a professional extension of your main communication channel. If deliverability ever dips, your primary domain stays safe.
Set up SPF, DKIM and DMARC
These three DNS records authenticate your emails and prove to providers that the messages are legitimate. Without them, your emails may be seen as untrusted.
- SPF confirms which platforms may send emails from your domain.
- DKIM adds a digital signature that verifies the message is authentic.
- DMARC tells inbox providers what to do if something fails, such as monitoring or blocking suspicious activity.
Adding these records usually takes ten to fifteen minutes. Most email platforms provide the exact values you need to copy into your DNS settings. Always recheck them when you add a new sending provider or set up a new domain.
Write outreach emails that look personal
Cold emails perform best when they look like genuine 1 to 1 communication. Heavy visuals, long pitches and attachments often trigger spam filters.
- Keep emails simple.
- Avoid HTML templates.
- Use short subject lines.
- Remove attachments and use links instead.
- Keep one clear purpose or one question per message.
This type of email is exactly what inbox providers expect from normal human communication, which improves your deliverability.
Test your deliverability regularly
- mail-tester.com – This shows how inbox providers score your email. Always send a real outreach email to the test address instead of using a tool’s internal test function. A score above 9.5 is ideal.
- Dmarcchecker.app – This checks the status of your SPF, DKIM and DMARC records. If anything is misconfigured, your messages are much more likely to be filtered.
Run these tests whenever you launch new sequences or change your sending setup.
Warm up new domains and mailboxes gradually
Brand new mailboxes should never start with high volume. Doing so signals suspicious behavior to providers and can cause immediate filtering.
- Begin with 10 to 20 emails per day.
- Increase volume slowly over two to four weeks.
- Monitor open and reply rates.
- Slow down if performance drops.
Once warmed up, most mailboxes can safely handle between 100 and 200 emails per day depending on engagement.
Build your email infrastructure with the right tools
Platforms like Smartlead and Instantly make outreach easier and safer. They allow you to connect multiple mailboxes, rotate senders, warm up automatically and track performance. You can even purchase pre-configured domains directly inside these tools if you want to outsource the technical setup.
Before launching any campaign, make sure all leads are verified. Use dynamic fields to personalize messages directly from your CSV. Sync replies and meetings back into your CRM or Google Sheets using Zapier, Make.com or webhooks.
Checklist before starting outreach
