Domain Strategy at Scale: Dedicated Domains vs Subdomains

Most outbound teams spend weeks debating whether to use a dedicated domain (companyoutreach.com) or a subdomain (go.company.com). They write pros and cons lists, read blog posts from 2018, and treat it as a one-time decision.

That entire debate is a distraction. It focuses on choosing a single asset, when the real challenge is managing a fleet.

In 2025, sending cold email at scale isn't about picking one perfect domain. It's an infrastructure problem. The winning strategy requires a dynamic portfolio of sending domains—both dedicated and subdomains—that you can rotate, warm up, and monitor automatically to protect your reputation and ensure deliverability.

The traditional approach was simple because the volume was low. A team would pick one domain—usually a slight variation of their main brand—set up a few inboxes, and start blasting.

This model creates a massive single point of failure. If that one domain gets flagged for spam or blacklisted, your entire outbound operation goes dark overnight. All your sequences stop, your leads dry up, and your main corporate domain's reputation might even be damaged by association.

This setup cannot handle the demands of sending 10k, 50k, or 100k+ emails per month. It's like trying to run an enterprise data center on a single desktop computer. It was never designed for that load, and it will inevitably fail.

Treating outbound as an infrastructure discipline means building a resilient, scalable system. Instead of relying on a single asset, you build a portfolio of sending domains and manage them programmatically.

This system has a few core components:

1. A Mixed Domain Portfolio: You don't choose one or the other. You use both. Dedicated domains (getcompany.io) are perfect for isolating new or high-risk campaigns. Subdomains (m.company.com) can be used for warmer outreach where leveraging the root domain's age is an advantage.
2. Inbox Pools: You create dozens or hundreds of inboxes spread across your domain portfolio. A pool of 50 inboxes across 5 domains is far more resilient than 50 inboxes on one domain.
3. Automated Warmup and Rotation: Manually warming up 50+ inboxes is impossible. An infrastructure platform automatically handles warmup schedules and rotates sending across the entire pool to keep individual domain/inbox volume low and safe.
4. Centralized Deliverability Monitoring: You need a single dashboard to monitor the health of all your domains—checking for blacklists, monitoring sender scores, and running placement tests to ensure you're hitting the inbox.

Your domain and inbox requirements scale with your volume. Here are three common infrastructure tiers we see with teams operating at scale.

The Starter Stack:

1. Setup: 1-2 dedicated domains, 3-5 inboxes.
2. Capacity: 75-125 cold emails/day (each inbox sends 25 cold + 25 warmup = 50 total/day).
3. Timeline: Requires a 2-3 week warmup period.
4. Use Case: For teams just starting a dedicated outbound function or testing initial messaging and offers. The goal is safety and learning.

The Growth Stack:

1. Setup: 2-3 dedicated domains, 10-15 inboxes.
2. Capacity: 250-375 cold emails/day (each inbox sends 25 cold + 25 warmup = 50 total/day).
3. Timeline: Requires a 3-4 week warmup period.
4. Use Case: For teams with validated sequences who need to increase volume for one or more sales reps.

The Agency / Enterprise Stack:

1. Setup: 5+ dedicated domains, 25-50+ inboxes.
2. Capacity: 625-1,250+ cold emails/day (each inbox sends 25 cold + 25 warmup = 50 total/day).
3. Timeline: Requires a 4-6 week warmup period.
4. Use Case: For agencies managing multiple client campaigns or enterprise teams with multiple SDRs sending high volume.

Transitioning to an infrastructure-first model doesn't happen overnight. It's a phased process.

Phase 1: Acquire and Configure Assets. Before sending a single email, purchase your portfolio of dedicated domains. Set up your subdomains. Correctly configure SPF, DKIM, and DMARC records for every single sending domain. This is the non-negotiable foundation.

Phase 2: Warmup and Baseline. Connect all your inboxes to an automated warmup tool. Let them run for at least 3-4 weeks to build a positive sending reputation with providers like Google and Microsoft. Do not rush this step.

Phase 3: Scale with Rotation. Begin sending low-volume campaigns, using software that automatically rotates sending across your entire pool of inboxes and domains. Monitor deliverability closely as you gradually increase send volume. The system, not manual effort, should manage the complexity.

This level of infrastructure management is beyond the scope of a CRM or a simple mail-merge plugin. Your CRM is for managing customer relationships, not for rotating 100 inboxes across 10 domains to ensure deliverability.

Trying to build this yourself with scripts is a full-time engineering project. This is why dedicated outbound platforms exist. They are the execution layer designed specifically for this job.

SuperSend is built as the dedicated outbound execution and infra layer that sits alongside your CRM and data tools. We manage the domains, inboxes, warmup, and multi-channel sequencing so your team can focus on writing good copy and talking to prospects.

The next step is understanding how this infrastructure powers real-world campaigns. Exploring different multi-channel sequence patterns shows how a solid domain strategy enables effective execution.