How to Check Who Your Email Service Provider (ESP) Is

Your daily email sending limit depends on the Email Service Provider (ESP) connected to your domain. That’s why identifying your ESP is an important first step before setting sending limits or starting email warm-up.

Luckily, it only takes a few seconds.

Why knowing your ESP matters

Different ESPs (like Google, Microsoft, Zoho, etc.) have different:

1. Daily sending limits
   Deliverability rules
   Spam filtering behavior

Knowing your ESP helps you:

1. Set safe daily sending limits
   Warm up your inbox correctly
   Avoid deliverability issues

Steps to identify your Email Service Provider (ESP)

Step 1: Visit MXToolbox

Go to mxtoolbox.com

Step 2: Enter your domain

Type your domain name (for example: yourcompany.com) into the search bar.

Step 3: Run MX Lookup

Click “MX Lookup” or press Enter.

Step 4: Check the results

You’ll instantly see your domain’s MX records. These records tell you which provider is handling your email.

Example

If the MX records show Microsoft Office, it means your emails are managed by Microsoft (Outlook, Microsoft 365).

Based on this, you should follow Microsoft’s recommended sending limits when configuring your email warm-up or outreach.

What to do after identifying your ESP

Once you know your ESP:

Set daily sending limits according to that provider

Configure warm-up properly

Avoid sending more emails than your ESP allows

This simple check helps protect your sender reputation and improves inbox placement.