What this does: The Inbox Warm Up add-on gradually builds your sending reputation by automatically exchanging emails with other SendX users in a controlled warm-up network. This signals to inbox providers that your domain is legitimate, improving your chances of landing in the primary inbox instead of spam.
When you need this: Use Inbox Warm Up when you have a new sending domain, haven't sent emails in a while, or notice your deliverability declining. It's especially important before launching major campaigns from a fresh domain.
Cost: $200 per month per sender email address
Step-by-Step Setup
Step 1: Access the Inbox Warm Up Add-on
Click on your profile icon in the navigation bar
Select Settings from the drop-down menu
In the Settings menu, click Add-ons
Select Inbox Warm Up from the list
Step 2: Choose Which Senders to Warm Up
In the Inbox Warm Up section, click the Settings tab
Review the list of available senders (these are your whitelisted email addresses in SendX)
Select which sender email addresses you want to warm up
To change a sender, click on the name and choose a different whitelisted email from the dropdown
Note: You can warm up multiple sender addresses simultaneously. Each sender you enable will be billed separately at $200/month.
Step 3: Add a Campaign Template
The warm-up process uses a sample campaign to make your emails look natural. Follow these steps:
Click Browse Campaigns to open the Campaigns area
Select a campaign template that matches the style and tone of emails you plan to send to real contacts
Click the Options icon (three dots) next to your chosen campaign
Select Set as Warm-up Template from the dropdown
Confirm by clicking Set as Warm-up Template in the popup
If you skip this step: SendX will automatically use a generic template designed according to email deliverability best practices. However, using your own template creates a more authentic warm-up pattern.
Step 4: Confirm Your Warm-up Settings
Navigate back to Settings > Add-ons
Click Inbox Warm Up in the list
In the Warm-up Settings section, verify:
The correct sender email is selected
Your chosen campaign template is displayed (or the default if you didn't select one)
Step 5: Enable the Add-on
Click the Overview tab
Toggle the switch at the top to enable the add-on
Once enabled, your inbox warm-up begins automatically. The add-on will handle the rest in the background.
Monitoring Your Warm-up Progress
Viewing Deliverability Reports
Go to the Inbox Warm Up add-on
Click the Reports tab
Select the domain you're monitoring from the dropdown
Review key metrics:
Deliverability percentage: How many emails reached the inbox vs. spam
Inbox placement rate: Percentage landing in primary inbox
Spam placement rate: Percentage filtered to spam or junk
Understanding Weekly Auto-Deliverability Tests
For detailed breakdowns by inbox provider (Gmail, Outlook, Yahoo, etc.):
In the Reports section, click Show Details
Review performance by provider to identify specific problem areas
Example: If Gmail shows 95% inbox placement but Outlook shows 60%, you may have a reputation issue specific to Microsoft's filters.
Important Notes & Limitations
Sender requirements: Only email addresses already whitelisted in SendX can be used for warm-up. If you need to add a new sender, whitelist it first through your SendX settings.
Multiple domains: If you operate multiple sending domains, each needs its own warm-up process. You can run these concurrently.
Billing: Each enabled sender is billed at $200/month. Make sure to disable senders you're no longer warming up to avoid unnecessary charges.
Template selection matters: Choose a campaign template that genuinely represents your sending style. Warm-up emails that don't match your actual campaigns may confuse inbox algorithms when you switch to real sends.
Common Questions
Q: How long does warm-up take?
A: Warm-up duration varies based on your domain's starting reputation and sending volume. Most senders see meaningful improvement within 2-4 weeks, but severely damaged reputations may take longer.
Q: Can I send regular campaigns while warming up?
A: Yes. Warm-up runs in the background and doesn't interfere with your normal sending. In fact, combining gradual warm-up with careful, low-volume real sends can accelerate reputation building.
Q: What if my deliverability reports show poor results?
A: If you're consistently seeing low inbox placement rates after several weeks, consider advanced tactics like sending from a dedicated IP address or customizing email routing. Contact SendX's professional services team for assistance with these configurations.
Q: Do warm-up emails count against my sending limits?
A: Warm-up emails are handled separately and do not consume your regular campaign credits or sending quota.
Q: Can I pause and resume warm-up?
A: You can disable the add-on at any time by toggling it off. However, stopping mid-warm-up may slow your progress. When you re-enable, warm-up resumes but doesn't restart from zero.
Q: What happens if I don't select my own template?
A: SendX uses a generic, best-practice template automatically. This works fine but may not perfectly match your brand voice or typical email structure.
Pro tip: Warm-up works best when combined with good list hygiene, proper authentication (SPF, DKIM, DMARC), and gradual volume increases in your actual campaigns. Think of it as one piece of a broader deliverability strategy, not a magic fix.