Best Practices IP Warmup for Transactional Email Using MailChannels By MailChannels | 3 minute read If you are sending transactional emails from a new IP address or domain, especially at scale, you should not start at full volume on day one. You need to build a positive sending reputation first. That is where IP warmup comes in. Whether you are moving to MailChannels from another provider or starting fresh, a proper warmup ensures password resets, receipts, and signup confirmations land in the inbox instead of spam. This guide explains 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 increase of email volume from a new IP. It allows mailbox providers such as Gmail, Microsoft, and Yahoo to observe sending behavior, verify authenticity, and assign a positive reputation over time. If you skip warmup and jump to high volume, messages are likely to be throttled or flagged. Do You Need to Warm Up with MailChannels? MailChannels offers shared and private IP infrastructure with built-in abuse prevention and reputation safeguards, which reduces warmup burden. You should still follow a plan if you are: Migrating from another provider Launching a new domain Sending higher volumes (> 5,000 daily) Using a dedicated IP pool In these cases, a warmup plan is highly recommended. MailChannels IP Warmup Best Practices 1. Start with Low Volume Begin with a small set of trusted recipients who are likely to engage. Suggested starting volume: Day 1: 250–500 emails Days 2–3: 1,000–2,000 emails Days 4–7: 3,000–5,000 emails Scale gradually over 2–4 weeks 2. Prioritize High-Engagement Messages Send only essential transactional messages at first: Password resets Account verifications Purchase receipts Login notifications These typically have high opens and low complaints, which build reputation. Explore common transactional use cases 3. Authenticate Your Domain Configure authentication before sending: SPF (Sender Policy Framework) DKIM (DomainKeys Identified Mail) DMARC (recommended) These signals prove you are legitimate. For help, see Key Components of a Transactional Email 4. Monitor Delivery Metrics Track performance closely and adjust pacing as needed: Open and click rates Bounce rates Spam complaints Rejected or deferred messages MailChannels provides dashboards and logs to monitor warmup. If errors spike or engagement drops, pause and investigate before increasing volume. 5. Avoid Marketing Content During Warmup Keep warmup traffic transactional-only. Avoid promotions, newsletters, and sales announcements, which raise complaint risk and can derail reputation. Why this matters: Transactional vs Marketing Email Common Mistakes to Avoid Skipping domain authentication Using purchased or cold lists Scaling volume too quickly Mixing marketing into warmup flows Ignoring bounce and complaint data Final Thoughts A disciplined IP warmup creates the foundation for long-term inbox placement and reputation. MailChannels helps by managing abuse and IP trust. For best results at higher volumes, follow a controlled warmup plan. Need help getting started? Use these guides: How to Send Transactional Email via SMTP Relay How to Integrate the MailChannels Email API Get started with the MailChannels Email API and scale with confidence.