Learning Objective
By the end of this guide, you'll know how to enable Matching ESP (called Email provider matchmaker in the app) in lemlist to send emails from the same email provider (Google or Microsoft) as your recipient, improving inbox placement and reply rates.
Why This Matters
Cold emails often land in spam instead of the inbox. Without Matching ESP:
❌ Your emails are flagged as "external" by spam filters
❌ Authentication checks (SPF/DKIM/DMARC) are stricter
❌ Inbox placement rates drop
❌ Reply rates suffer
Using Matching ESP helps you:
✅ Send Gmail → Gmail or Outlook → Outlook (trusted "internal" delivery)
✅ Pass authentication checks more easily
✅ Improve inbox placement
✅ Increase open and reply rates
Prerequisites
At least 1 Google Workspace mailbox connected to lemlist
At least 1 Microsoft 365 mailbox connected to lemlist
Active campaign with leads imported
Understanding of email providers (Google Workspace, Microsoft 365, etc.)
What Is Matching ESP?
Matching ESP (a.k.a. Email provider matchmaker) sends emails to recipients using the same email service provider they use.
Example:
Recipient uses Google Workspace → lemlist sends from your Google Workspace mailbox
Recipient uses Microsoft 365 → lemlist sends from your Microsoft 365 mailbox
Why it works:
Server-to-server communication is recognized as "safe"
Authentication (SPF/DKIM/DMARC) passes more easily
Spam filters see fewer red flags
Delivery is faster (lower latency)
Result: Better inbox placement, higher open/reply rates, lower spam rates.
How Matching ESP Works
Lead enters campaign
lemlist checks the lead's email domain (e.g.,
[email protected]→ checkscompany.com)System looks up MX DNS records to identify the email provider:
Google Workspace
Microsoft 365
Other/Unknown
When sending:
If provider matches → lemlist uses a sender with the same ESP
If provider doesn't match (or is unknown) → email is sent from the default sender pool
Example Logic
Recipient's ESP | Do You Have Matching Mailbox? | What Happens |
Google Workspace | Yes ✅ | Sent via your Google sender |
Google Workspace | No ❌ | Sent via default sender pool |
Microsoft 365 | Yes ✅ | Sent via your Microsoft sender |
Microsoft 365 | No ❌ | Sent via default sender pool |
Unknown / Other | — | Sent via default sender pool |
Step 1: Connect Google and Microsoft Mailboxes
Before enabling Matching ESP, connect at least one mailbox from each provider.
From your lemlist dashboard, click your name in the bottom-left, then select Settings
Open Sending settings, make sure you are in the Email section, then click Connect email address and follow the prompts to connect your Google Workspace and Microsoft 365 mailboxes
Step 2: Enable Matching ESP (Team Level)
Enabling this at the team level applies it to all campaigns in your workspace by default.
In Sending settings, click the Team tab
Turn on Deliverability boost: Email provider matchmaker
Result: All campaigns now use Matching ESP by default.
You can still disable/override it for a specific campaign if needed.
Step 3: Enable Matching ESP (Campaign Level)
Use this if you only want Matching ESP for one specific campaign.
Go to Campaigns, then open the campaign you want to edit
Click the Settings (gear icon) in the campaign, then enable Deliverability boost: Email provider matchmaker in General settings
Result: Only this campaign uses Matching ESP.
How You'll Know It Worked
✓ Email provider matchmaker is enabled (team-level or campaign-level)
✓ Emails are sent from matched providers when possible (review your sending behavior in campaign analytics)
✓ Inbox placement improves (fewer spam folder placements)
✓ Open and reply rates increase compared to campaigns without Matching ESP
✓ Bounce rates decrease (fewer authentication failures)
Troubleshooting
Issue: Email provider matchmaker toggle is grayed out
Root cause: You don't have both a Google and a Microsoft mailbox connected.
Fix: Connect at least 1 Google Workspace mailbox and at least 1 Microsoft 365 mailbox in Settings → Sending settings.
Issue: Emails still sent from the "wrong" provider
Root cause: The lead's email provider is unknown or not Google/Microsoft.
Fix: This is expected behavior. lemlist matches Google and Microsoft. If the lead uses another provider (e.g., Yahoo, custom domain hosted elsewhere), lemlist uses your default sender pool.
Issue: Matching ESP not improving deliverability
Root cause: Other deliverability issues (poor domain reputation, high bounce rate, spam content).
Fix:
Verify SPF/DKIM/DMARC are configured correctly
Check domain reputation (Google Postmaster Tools)
Warm up your email addresses (use lemwarm)
Remove spam-trigger words from email content
Issue: Not enough sending capacity with matched mailboxes
Root cause: You have 5 Google mailboxes but only 1 Microsoft mailbox. Microsoft leads aren't distributed evenly.
Fix: Add more Microsoft 365 mailboxes to balance capacity across providers.
Optimization Tips
Balance your mailbox providers: If 60% of your leads use Google and 40% use Microsoft, connect a similar ratio of mailboxes (e.g., 6 Google, 4 Microsoft).
Check lead provider distribution: Before enabling Matching ESP, analyze your lead list to see how many use Google vs. Microsoft. Focus your mailbox setup accordingly.
Use Matching ESP for cold outreach: This feature works best for cold email campaigns where deliverability is critical. Less important for warm follow-ups or existing relationships.
Monitor inbox placement: Use tools like Mail-Tester or GlockApps to test inbox placement before and after enabling Matching ESP.
Combine with other deliverability tactics: Matching ESP works best when combined with proper authentication (SPF/DKIM/DMARC), warm-up (lemwarm), and clean email lists.
Test with A/B campaigns: Run one campaign with Matching ESP ON and one with it OFF. Compare inbox placement and reply rates to measure impact.
Why This Works (Simple Explanation)
Gmail → Gmail = trusted "internal" delivery
Outlook → Outlook = trusted "internal" delivery
Emails sent within the same network face fewer security checks and are less likely to be flagged as spam. It's like sending a message inside the same company network instead of from the outside.