Best Practices

IP Warmup for Transactional Email Using MailChannels

By MailChannels | 3 minute read

If you’re sending transactional emails from a new IP address or domain, especially at scale, you can’t just start blasting full volume on Day 1. You need to build a positive sending reputation first. That’s where IP warmup comes in.

Whether you’re moving to MailChannels from another provider or starting fresh, properly warming up your IP ensures your password resets, receipts, and signup confirmations actually reach the inbox, not the spam folder.

In this post, we’ll walk you through how to warm up your IP for transactional email using MailChannels, why it matters, and how to avoid common pitfalls.

What Is IP Warmup?

IP warmup is the gradual process of increasing the volume of email you send from a new IP address. It allows mailbox providers like Gmail, Microsoft, and Yahoo to observe your sending behavior, verify your authenticity, and assign your IP a positive reputation over time.

If you skip warmup and go from zero to thousands of emails per day, your messages are likely to get flagged or throttled.

Do You Need to Warm Up with MailChannels?

MailChannels offers shared and private IP infrastructure, and our system includes built-in abuse prevention and reputation safeguards. This helps reduce warmup requirements—but if you’re:

Migrating from another provider
Launching a new domain
Sending higher volumes (>5,000 daily)
Using a dedicated IP pool

… then a warmup plan is highly recommended.

MailChannels IP Warmup Best Practices

1. Start with Low Volume

Begin with a low volume of trusted recipients, users who are likely to engage (open, click, or reply).

Suggested starting volume:

Day 1: 250–500 emails
Day 2–3: 1,000–2,000 emails
Day 4–7: 3,000–5,000 emails
Scale up gradually over 2–4 weeks

2. Prioritize High-Engagement Messages

Send only essential transactional messages at first, things like:

Password resets
Account verifications
Purchase receipts
Login notifications

These tend to have high open rates and low complaints, which help build a clean sender reputation.

Explore these use cases: Common Use Cases for Transactional Email

3. Authenticate Your Domain

Before sending a single email, make sure your domain is correctly configured with:

SPF (Sender Policy Framework)
DKIM (DomainKeys Identified Mail)
DMARC (optional, but recommended)

These signals show mailbox providers that you’re a legitimate sender. For help setting this up, see Key Components of a Transactional Email

4. Monitor Delivery Metrics

Keep an eye on:

Open and click rates
Bounce rates
Spam complaints
Rejected or deferred messages

MailChannels provides detailed dashboards and logs for monitoring your warmup performance. Any sudden spike in errors or drop in engagement? Pause and investigate before scaling further.

5. Avoid Marketing Content During Warmup

This warmup should be transactional-only. Avoid promotions, newsletters, or sales announcements, these carry a higher risk of spam complaints and can derail your warmup.

Want to know why that matters? Read: What Is Transactional Email? (vs Marketing Email)

Common Mistakes to Avoid

Skipping domain authentication
Using purchased or cold lists
Jumping volume too quickly
Mixing marketing emails into warmup flows
Ignoring bounce and complaint data

Final Thoughts

A successful IP warmup sets the foundation for long-term inbox placement and reputation health. MailChannels’ infrastructure makes warmup easier by actively managing abuse and maintaining IP trust, but for best results, especially at higher volumes, following a controlled warmup plan is key.

Need help getting started? Explore our integration guides:

And when you’re ready to scale with confidence, get started with MailChannels Email API