# Cold Email Deliverability Setup for a New Domain > How to set up a new domain for cold email, including authentication, inbox warm-up, list verification, sending limits and monitoring. Source: https://comppound.com/blog/cold-email-deliverability-setup-for-a-new-domain (published 2026-07-08) Deliverability decides whether your cold emails land in the inbox or the spam folder. A thoughtful, well-targeted email that lands in spam gets no replies, and you may never know why. For founders and small teams starting outbound, a careful cold email deliverability setup on a new sending domain is the foundation everything else rests on. It takes a few weeks to do properly, and most of that time is waiting, which is exactly why teams are tempted to skip steps. This guide covers the setup in the order you should do it, explains why each step matters and describes what to do when deliverability drops anyway. ## Why use a separate domain Sending cold email from your main company domain puts your primary email reputation at risk. Mailbox providers track how recipients react to mail from each domain. If your cold emails generate spam complaints or bounces, that reputation suffers, and the damage spreads to everything else you send from the same domain, including invoices, support replies, password resets and onboarding emails. A deliverability problem that starts in outbound can end with customers not receiving their receipts. Most teams register a similar domain for outreach. If your company is example.com, you might use getexample.com, tryexample.com or example-hq.com. Pick something that clearly relates to your brand so recipients recognize it, and avoid names that look like a typo of your main domain, which can seem like phishing. Set the outreach domain to redirect to your main website, so anyone who types it into a browser lands somewhere legitimate. A separate domain is not a license to send carelessly. Its reputation still matters, and recipients still see your company name. It simply limits how far a mistake can spread. ## Step 1: Register the domain and set up mailboxes Register the domain, then set up mailboxes through a reputable email provider, the same kind you would use for normal business email. Avoid cheap or obscure providers whose sending infrastructure may already have a poor reputation. Create mailboxes with real names, such as firstname@ rather than sales@ or outreach@. People reply to people. A generic role address signals a mass campaign and invites both lower reply rates and more spam reports. Add a profile photo and a normal signature with your name, title and company. These details make the mailbox look like what it should be: a real person at a real company. If you plan to send meaningful volume, set up more than one mailbox from the start. Spreading volume across several inboxes is safer than pushing one hard, and setting them up together means they warm up on the same timeline. ## Step 2: Configure authentication Authentication proves to receiving servers that you are allowed to send email from your domain. Without it, many providers will treat your mail with suspicion or reject it outright. There are three records to set up. SPF, or Sender Policy Framework, is a DNS record that lists the servers allowed to send email for your domain. When a receiving server gets a message claiming to come from your domain, it checks whether the sending server is on that list. If you send through both your email provider and an outreach tool, both may need to be included, so check each tool's documentation. DKIM, or DomainKeys Identified Mail, adds a cryptographic signature to each email. The receiving server verifies that signature using a public key published in your DNS. A valid DKIM signature shows the message was not altered in transit and really came from a server you authorized. DMARC is a policy that tells receiving servers what to do when SPF or DKIM checks fail, and where to send reports about those failures. Start with a monitoring policy, which asks for reports without instructing servers to reject anything. Once the reports show that all your legitimate mail passes, tighten the policy so failing messages are quarantined or rejected. Your email provider will give specific instructions for each record. After setup, use a free checker tool to confirm that all three pass. DNS changes can take time to propagate, so check again a day later before you start warming up. ## Step 3: Set up a custom tracking domain, or skip tracking If your outreach tool tracks link clicks, it rewrites links in your emails to point through its own domain. By default, that is often a shared domain used by many customers, some of whom send poor-quality mail. Configure a custom tracking domain so your links use a subdomain of your own outreach domain instead. Many teams turn off open tracking entirely. Open tracking works by embedding a small invisible image, and that pattern can count against you with some spam filters. Open data has also become less reliable as mail clients load images automatically or block them. Replies are a better signal of whether your outreach is working, and they don't require any tracking at all. ## Step 4: Warm up the inboxes New domains and mailboxes have no reputation. To a mailbox provider, a brand-new domain that suddenly sends hundreds of emails to strangers looks exactly like a spammer. Warm-up builds a sending history gradually, so providers learn to trust you. Start by sending a small number of genuine emails each day and increase the volume slowly over several weeks. Use the mailbox for real conversations: emails to colleagues, partners and contacts who will reply. Replies are a strong positive signal. Warm-up services, which exchange automated emails between networks of inboxes, can help, but they are a supplement. Genuine sending behavior matters most, and relying entirely on automated warm-up can create a reputation that collapses once real outreach begins. Be patient. Rushing warm-up is one of the most common causes of early deliverability problems, and recovering a burned domain often takes longer than doing it slowly in the first place. A team that registers a domain on Monday and sends a full campaign on Friday has usually created the problem it will spend the next month diagnosing. ## Step 5: Verify your list Bounces damage sender reputation quickly, because sending to addresses that don't exist is a classic sign of a scraped or purchased list. Before sending, run every address through a verification tool and remove invalid and risky ones. Be careful with catch-all domains. These are domains configured to accept mail for any address, so verification tools can't confirm whether a specific mailbox exists. Some will bounce later, and some will silently disappear. Many teams send to catch-all addresses in small, separate batches, or only when they have strong evidence that the address is correct. Avoid purchased lists of unknown quality. Even when they verify cleanly, they often include people who have no reason to hear from you, which leads to spam complaints. A smaller list of well-researched contacts protects your reputation and produces better conversations. ## Step 6: Set sending limits Keep daily volume per mailbox modest. There is no universal safe number, since it depends on your provider, your domain's history and how recipients respond, but the principle is consistent: steady, moderate sending looks normal, while sudden spikes look suspicious. Many teams spread volume across multiple mailboxes on the outreach domain rather than pushing one inbox hard. When you increase volume, do it slowly and watch your metrics after each increase. If bounces or complaints rise, step back to the previous level before investigating. ## Step 7: Write deliverability-friendly emails Content affects deliverability as well as reply rates. Plain text with minimal formatting looks like a normal email between people and avoids the patterns filters associate with marketing blasts. Limit links, ideally to one or none in the first email, and avoid attachments, which are a common vector for malware and trigger extra scrutiny. Skip spammy phrases, excessive punctuation and all-caps subject lines. Personalize genuinely. Inserting a first name and company name is the minimum, and recipients see through it. A sentence that shows you understand the recipient's situation, such as a reference to a role they are hiring for or a product they recently launched, makes the email relevant. Include a clear, simple way to opt out, like a line inviting them to reply if they'd rather not hear from you. Relevance matters most of all. Emails that recipients reply to build your reputation. Emails that get marked as spam damage it. Good targeting is a deliverability strategy. ## Step 8: Monitor Once you are sending, watch a handful of signals. Keep your bounce rate very low, and investigate any rise immediately, since it usually points to a list problem. Monitor spam complaints through the postmaster tools that some mailbox providers offer. Track your reply rate, because a sudden drop with no change in targeting or copy can signal that emails have started landing in spam. Run inbox placement tests periodically by sending to a set of test inboxes across different providers and checking where your emails land. Check whether your domain or sending IP appears on major blocklists. None of this takes long once it becomes a weekly habit, and it lets you catch problems before they become severe. ## Step 9: Handle replies and opt-outs Reply promptly to responses, positive or negative. Honor opt-out requests immediately and make sure the person is removed from every sequence and every mailbox, not just the one they replied to. Stop all automated follow-ups when someone replies, so they don't receive a "just bumping this up" message after already answering. That kind of mistake generates spam complaints from people who were willing to talk. ## Step 10: Follow the law Cold email rules vary by country, and some regions are much stricter than others. Common requirements include identifying yourself honestly, including a physical mailing address, providing a way to opt out and having a legitimate reason to contact the person. Understand the rules for each region you email, and get advice if you plan to send to places with strict consent requirements. ## If deliverability drops If replies suddenly fall or placement tests show emails landing in spam, pause or reduce sending first. Continuing to send while the reputation is falling makes recovery harder. Then check your authentication records, since a DNS change or a new tool can break SPF or DKIM without anyone noticing. Next, review your bounce and complaint rates and look for recent changes in content, list source or volume. Deliverability problems almost always follow a change, such as a new list vendor, a new template with several links or a jump in daily sends. Fix what you find, then resume slowly, ramping up as if the mailbox were partly warming up again. ## The takeaway A deliverability-ready setup has a separate domain, proper authentication, patient warm-up, verified lists, modest volume, relevant plain-text emails and ongoing monitoring. None of these steps is complicated, but skipping any of them can undo the rest. Do the setup before you write your first sequence, give warm-up the weeks it needs, and treat replies and complaints as the signals that tell you whether your outreach deserves to keep reaching the inbox. ## Keep reading - [Cold Email Subject Lines for B2B SaaS](/blog/cold-email-subject-lines-for-b2b-saas) - [SEO for a Brand-New SaaS Domain: The First 90 Days](/blog/seo-for-a-brand-new-saas-domain-the-first-90-days) - [Personalization at Scale in Cold Email](/blog/personalization-at-scale-in-cold-email) ## Frequently asked questions ### How long should I warm up a new cold email domain? Typically several weeks of gradually increasing volume, while monitoring bounces and replies. ### Should I use my main domain for cold email? Generally no. A separate but related domain protects your main domain's reputation. ### Do I need SPF, DKIM and DMARC for cold email? Yes. They are basic authentication requirements for good deliverability. ## About Comppound Comppound runs SEO and AI search for B2B SaaS companies: a person sets the plan and reviews samples and every high-risk page, and AI speeds up production. - [Get the free report](https://comppound.com/ai-visibility-report): When buyers ask ChatGPT about your category, are you in the answer? - [See pricing](https://comppound.com/pricing): Want the content written, reviewed and published for you?