Email Warmup Strategy for New Domains

Most teams warming up new domains follow a playbook from 2018: buy a domain, connect it to a warmup tool, wait two weeks, and start blasting. This used to work when mailbox providers were less sophisticated.

In 2025, that strategy is a direct path to the spam folder. Google and Microsoft's filtering algorithms no longer just look at the age of a domain; they analyze the entire sending infrastructure, the pattern of activity, and the reputation across a network of related assets. Treating warmup as a simple, one-time checklist item for a single domain is the most common reason high-volume outbound campaigns fail before they even start.

A modern warmup strategy isn't about fooling a filter for two weeks. It's about building a resilient, scalable sending infrastructure. It requires thinking like an operator, not a marketer. You're not just 'warming up a domain'; you are cultivating a portfolio of sending assets designed to protect your reputation and deliver messages at scale.

The old approach to outbound was dangerously simple. A team would buy one new domain, maybe company-inc.com to supplement company.com.

They'd create a single inbox like kurtis@company-inc.com, hook it into a generic mail merge tool, and run a basic warmup sequence for 14 days. After that, they'd load up a list of 5,000 leads and hit send, blasting hundreds of emails a day from that one inbox.

This breaks instantly in 2025. Mailbox providers see the sudden spike from zero to 500 sends a day as a massive red flag. The single domain has no established reputation, and a single point of failure means one spam report can burn the entire asset. It's a fragile, transparently automated setup that gets shut down immediately.

An infrastructure-first approach treats domains and inboxes as a managed portfolio. The goal is not to warm up a single domain but to build a resilient system for sending.

This model is built on several core components:

1. Domain Pools: Instead of one sending domain, you operate with a pool of 3, 5, or even 20+ domains. This distributes risk. If one domain's reputation dips, the others in the pool continue sending, protecting your overall volume.
2. Inbox Rotation: Each domain has multiple inboxes (e.g., 3-5 per domain). Sending is automatically rotated across all active inboxes, keeping the volume per inbox low and looking natural. Sending 300 emails from 10 inboxes is safer than sending 300 from one.
3. Gradual, Continuous Warmup: Warmup isn't a two-week event; it's a continuous process. New inboxes are gradually ramped over 3-4 weeks. Even after ramp-up, they continue to participate in automated warmup conversations to maintain their reputation.
4. Strict Send Limits: Each inbox adheres to strict daily limits—typically no more than 25-30 new cold emails per day, supplemented by warmup activity. This mimics human behavior and avoids triggering volume-based filters.

Transitioning to an infrastructure-first model doesn't happen overnight. It's a phased process focused on building a stable foundation first.

Phase 1: Build and Stabilize Infrastructure (Weeks 1-4)

Forget about sending campaigns. Your only job is to acquire new domains, set up SPF, DKIM, and DMARC correctly, create your inbox pools, and begin the automated warmup process. Monitor deliverability but do not send any cold outreach.

Phase 2: Introduce Low-Volume Sequences (Weeks 5-8)

Once your inboxes are fully warmed, start sending low-volume, high-quality campaigns. Send no more than 20-25 cold emails per inbox per day. The goal here is to validate your messaging and targeting while establishing a positive sending history with real engagement.

Phase 3: Scale and Optimize (Week 9+)

With a stable infrastructure and validated sequences, you can now scale. This doesn't mean dramatically increasing emails per inbox. It means adding more inboxes and domains to your pool to increase your total sending capacity safely.

You cannot manage a portfolio of 50+ inboxes and 10+ domains from your CRM or a simple mail merge plugin. These tools are not built for infrastructure management; they are built for relationship management.

Your CRM sending emails is a risk to your primary domain. A Gmail plugin cannot rotate domains, manage warmup across a pool, or monitor deliverability at scale. Trying to DIY this with scripts is a full-time engineering job.

SuperSend is built as the dedicated outbound execution and infra layer that sits alongside your CRM and data tools. It handles domain rotation, inbox warmup, and multi-channel sequencing automatically.

Once your infrastructure mindset is in place, the next step is to explore proven sequence patterns that leverage this kind of setup. This is how you translate a strong foundation into actual meetings.