Safely warm up your sending domain
UpdatedTo ensure your emails successfully reach your recipients, it’s important to build a good reputation for the domain you’re sending emails from, which is where a domain warm-up process comes in.
Overview
Think of warming up your domain like introducing yourself to email providers (like Gmail, Yahoo, etc.) and saying, “Hi, I’m trustworthy and send relevant, valuable emails.” If you suddenly start sending large amounts of emails from a domain that hasn’t sent much before, it’s like yelling into a quiet room — inbox providers may see this as suspicious and will block or filter your emails.
By sending small, controlled batches of emails first and gradually increasing the volume over time, you show email providers that:
- Your emails are legitimate.
- Recipients are engaging with your messages (opening & clicking).
- You’re not spamming people or sending unwanted messages.
This structured approach helps you build trust with inbox providers and ensures your emails land in inboxes instead of spam folders. It’s especially critical for new domains or those without a solid history of sending emails, as ISPs use this history to evaluate your trustworthiness.
Warm-up schedule for established sending domains
If your sending domain already has a history, we recommend the following ramp-up schedule. Each stage typically lasts one day.
Daily and hourly message rates for established domains
| Stage / Day | Daily Message Rate | Hourly Message Rate |
|---|---|---|
| 1 | 1,000 | 100 |
| 2 | 2,500 | 300 |
| 3 | 5,000 | 600 |
| 4 | 6,500 | 800 |
| 5 | 8,000 | 1,000 |
| 6 | 10,000 | 1,500 |
| 7 | 14,000 | 2,000 |
| 8 | 20,000 | 3,000 |
| 9 | 25,000 | 3,500 |
| 10 | 35,000 | 4,500 |
| 11 | 50,000 | 6,500 |
| 12 | 80,000 | 10,000 |
| 13 | 125,000 | 16,000 |
| 14 | 175,000 | 25,000 |
| 15 | 250,000 | 50,000 |
Key Notes:
- The daily limit is more critical than the hourly rate, but we recommend applying rate limiting whenever possible.
- Never send more than double the volume from the previous stage on any given day.
Warm-up schedule for new domains
If your domain is brand new and has no recent traffic, start much slower. Use the following plan tailored for new domains:
Daily message rates for new domains
| Stage / Day | Daily Message Rate |
|---|---|
| 1 | 100 |
| 2 | 200 |
| 3 | 350 |
| 4 | 500 |
| 5 | 750 |
| 6 | 1,000 |
| 7 | 1,500 |
| 8 | 2,000 |
| 9 | 3,000 |
| 10 | 5,000 |
| 11 | 8,000 |
| 12 | 15,000 |
| 13 | 25,000 |
| 14 | 50,000 |
Core best practices
- Start with your best subscribers:
- Always front-load the initial cohorts with your most engaged subscribers based on email open activity (not in-app or purchase activity). Engagement metrics are critical during warm-up.
- Limit volume increases:
- Never send more than double the volume from the previous stage. For lists exceeding the totals in the charts above, follow the rule of doubling after day 15.
- Focus on recent engagement:
- Only warm up with subscribers who have opened emails within the last 120 days.
- Use recommended practices:
- Refer to our Email Deliverability Best Practices for additional tips on maintaining deliverability.
- Warm up only to your regular sending volume:
- You only need to warm up your domain to the maximum number of emails you plan to send regularly. For example, even if you have 100,000 subscribers, if you only send bulk emails to 35,000 of them on a regular basis, you only need to warm your sending capacity to 35,000. This helps avoid unnecessary volume increases and maintains deliverability.
Broadcasts vs Campaigns
- Broadcasts: Easier to troubleshoot in case of issues or unexpected results. Ideal for most warm-up scenarios.
- Campaigns: Some clients use campaigns with low volumes, starting a new one each day during the warming period to align with the ramp-up schedule. Either method works as long as you adhere to the plan.
