Updated: March 2026
Three years ago, launching a cold email campaign meant waiting. You'd buy domains, set up inboxes, then run "warmup" for 3-6 weeks—sending fake emails to fake addresses to convince Gmail you weren't a spammer. By the time you started real outreach, your enthusiasm (and budget) had evaporated.
That wait is now optional. But the way most providers talk about "no warmup" is misleading. You can't just blast 1,000 emails on day one and expect deliverability. The game has changed, not disappeared.
At ColdSend, we're dedicated to solving the warmup problem for agencies. Right now, that means Azure Communication Services. Tomorrow, it might mean other infrastructure layers—we're exploring several dimensions. But the constant is this: our sequencer is solid regardless of how you connect your inboxes. If warmup is a concern for you, migrating to ColdSend makes sense now, because you get immediate relief and a platform that keeps improving.
Here's how it actually works.
The Real Constraint
The old bottleneck was IP reputation. Every new sender got a fresh IP address with no history, so you had to "warm" it gradually. That's largely solved—Azure Communication Services (ACS) and similar enterprise pools already have trusted IPs.
The new bottleneck is domain reputation. When you send from you@yourcompany.com, Gmail looks at your domain's history. New domain = unknown = suspicious. You still need to build trust, but you can do it with real emails instead of fake warmup conversations.
What this means practically:
- Start sending immediately on ACS (good IPs carry you)
- Send 20-30 emails per inbox day one (not 200)
- Scale to 50-70 by week two, 100+ by week three
- Your domain reputation builds through actual engagement, not artificial chitchat
The providers telling you to send 500 emails per inbox on day one are lying. The providers making you wait a month to send anything are obsolete.
The ColdSend Playbook
We built ColdSend around a specific strategy: use ACS to fast-track domain reputation, then migrate to your own infrastructure. You can stay on ACS indefinitely, but most high-volume senders eventually hit the limits.
Why ACS First?
Azure Communication Services gives you:
- Enterprise IP pools (90+ reputation scores out of the box)
- ~96,000 emails per month per Azure account
- 4 domains, 100 inboxes per domain
- No artificial warmup period
You connect your own Azure account (we'll show you how—takes 5 minutes, costs ~$2/month). You own the infrastructure. We're just the sequencer and automation layer on top.
The Rotation Strategy
Here's where it gets interesting. You have two ways to scale:
Option A: Parallel Track
- Run real campaigns on ACS domains (building reputation through actual sends)
- Simultaneously warm up other domains through traditional methods
- Swap when ready
Option B: Sequential Rotation (our recommendation for agencies)
- Month 1: New domains on ACS, sending 20-100 emails/day
- Month 2: Domains show "Medium" or "High" reputation in Google Postmaster
- Month 3: Move those domains to Google Workspace/Outlook, put fresh domains on ACS
- Repeat to scale indefinitely
Why move domains off ACS? Because 96K emails is plenty for most businesses, but agencies need volume. Once a domain has reputation, it performs fine on standard infrastructure. ACS becomes your domain reputation accelerator, not your permanent home.
Month-by-Month: What Actually Happens
Week 1
- Set up Azure account (5 minutes)
- Connect to ColdSend, configure 4 domains
- DNS records auto-generated
- Start sending: 20-30 emails per inbox per day
- Check Google Postmaster daily
Week 2-3
- Ramp to 50-70 emails per inbox as reputation builds
- Watch bounce rates (should stay under 5%)
- Reply to every response quickly (reputation signal)
Month 2
- Domains hitting "Medium" reputation in Postmaster
- Consider: stay on ACS or start migration?
Month 3+
- If scaling: move warmed domains to Google Workspace/Outlook
- Import into ColdSend Scale plan
- Put new domains on ACS, repeat cycle
- If not scaling: stay on Alpha, add more Azure accounts as needed
The Downsides
This isn't magic. Three things will still get you blocked:
-
Bad lists. If you're scraping emails or buying lists, you'll hit spam traps regardless of infrastructure. ACS doesn't fix garbage data.
-
Aggressive ramping. Going from 0 to 100 emails per inbox in 48 hours looks robotic. The algorithm is watching your pattern, not just your volume.
-
No replies. If nobody responds to your emails, Gmail notices. Warmup tools used to fake this with reciprocal opens. We don't. Your copy actually has to work.
Who Should Use What
ColdSend Alpha ($249/month) if:
- You're starting fresh and want to skip the waiting period
- You send under 96K emails monthly
- You want to own your infrastructure (BYOA)
- You're building domain reputation before migrating to Scale
ColdSend Scale ($79/month) if:
- You already have warmed-up inboxes
- You send 100K+ emails monthly
- You need API access and team features
- You've outgrown Alpha and migrated your domains
ColdSend Starter ($39/month) if:
- You're testing with a handful of existing Gmail accounts
- You just need a better sequencer than what you're using
Bottom Line
You don't need to wait a month to start cold email. You also can't ignore reputation entirely. The middle path: start immediately on enterprise infrastructure, build domain reputation through real (conservative) sending, then scale or migrate as needed.
The warmup industry convinced everyone that waiting was mandatory. It isn't. But the "blast 10,000 emails on day one" crowd is just as wrong. The truth is in the middle: start fast, ramp smart, own your infrastructure.
And if you're worried about betting on a single approach—don't. We're committed to solving warmup for agencies long-term. ACS is our solution today. The sequencer is the foundation. Migrate for the warmup, stay for the workflow.
Ready to skip the wait? Start with Alpha and get your first campaign out this week. Already have warmed inboxes? Jump to Scale.
Tools to help:
- Find your Ideal Customer Profile — know who to email before you start
- Generate email variations with Spintax — avoid sending identical copy
- Compare infrastructure options — see how we stack up
