Warming up is the process of gradually introducing mail from a new source so that spam filters and reputation models can build trust in the new stream of messages.
Why Warming Matters
Mailbox providers (like Gmail, Outlook, and Yahoo) evaluate both your IP address and sending domain reputation based on recipient engagement (opens, clicks, replies), complaint rates, and bounce activity. Sending too many emails too quickly from a new or dormant domain/IP can raise red flags, leading to blocked or filtered messages.
A warm-up plan helps you build a positive sending reputation for both your IPs and domains. By starting small and scaling gradually, you show providers that your mail is wanted and trustworthy.
What is IP & Domain Warm-Up
Warm-up is the process of gradually increasing the volume of email sent from a new or unused dedicated IP address and/or a new sending domain or subdomain. The goal is to demonstrate consistent, responsible sending so that mailbox providers begin to trust both your IP and your domain. Done right, warm-up improves inbox placement and reduces the risk of throttling or blocking. Done too aggressively, it can result in poor deliverability and long-term reputation challenges for both IPs and domains.
Warm-Up Timeline
Warming typically takes 30–90 days depending on your audience size, sending volume, and audience engagement. The key is to: - Start with your most engaged recipients. - Increase volume gradually, never more than 2x the previous day’s volume. - Monitor performance and adjust pace as needed.
Step 1: Start With Your Most Engaged Audience
- Send first to recipients who want your email. These are likely users that consistently open, click, or interact with your emails.
- Prioritize transactional and highly engaged marketing campaigns (e.g., order confirmations, newsletters, product updates).
- Avoid sending to inactive or win-back lists early. Low engagement here can damage your reputation for both IPs and domains.
Step 2: Gradually Increase Volume
- Expand daily volume in controlled increments.
- Rule of thumb: don’t increase by more than 2x the previous day’s volume.
- Example: If you send 500 messages on Day 4, send no more than 1,000 on Day 5 if performance is strong.
30-Day Warm-Up Schedule (Sample Plan):
|
Day of Warm-up |
Daily Volume |
|
1 |
50 |
|
2 |
100 |
|
3 |
200 |
|
4 |
400 |
|
5 |
750 |
|
6 |
1,000 |
|
7 |
2,000 |
|
8 |
3,000 |
|
9 |
5,000 |
|
10 |
7,000 |
|
11 |
10,000 |
|
12 |
15,000 |
|
13 |
20,000 |
|
14 |
25,000 |
|
15 |
30,000 |
|
16 |
40,000 |
|
17 |
50,000 |
|
18 |
60,000 |
|
19 |
75,000 |
|
20 |
90,000 |
|
21 |
105,000 |
|
22 |
130,000 |
|
23 |
150,000 |
|
24 |
175,000 |
|
25 |
200,000 |
|
26 |
250,000 |
|
27 |
300,000 |
|
28 |
350,000 |
|
29 |
400,000 |
|
30 |
500,000 |
Step 3: Monitor Key Reputation Signals
Track these metrics as you warm up your IPs and domains:- High engagement (Target open rates >40%)
- Low bounce rates (Target sub 1% soft+hard bounce rates)
- Low complaint rates (Target for complaint rates below 0.1%)
- Consistent delivery times (95th Percentile Time to Delivery < 30s)
If engagement drops or complaints rise, pause your ramp-up. Focus on your most engaged recipients until performance stabilizes.
Step 4: Expand Your Audience
Once you have a solid reputation on both your IP and sending domain:- Slowly add less engaged recipients
- Maintain consistent cadence and volume growth
- Separate transactional and marketing traffic when possible
SocketLabs Best Practices
- Set up Authentication on your sending domain(s) before you start
- Keep warm-up volume steady and avoid spikes in sending
- Monitor performance by mailbox provider and adjust pacing if needed
- Continue list hygiene and engagement strategies after warm-up completes
Key Takeaways
- Warming takes time (30–90 days)
- Applies to both new IPs and new sending domains
- Start with your most engaged contacts
- Increase daily volume gradually, no more than 2x per day if metrics stay healthy
- Monitor engagement, bounces, and complaints closely
- Keep sending consistently to maintain reputation once warm-up is complete
By following these steps you’ll build a strong sending reputation across both your IP addresses and domains, improving inbox placement and long-term deliverability.