Email Infrastructure
Setting Up a Custom SMTP Service
Connect your own third-party email sending service — Gmail, SendGrid, Mailgun, Amazon SES, and more — directly inside your sub-account.
Overview

The platform allows you to connect your own third-party email sending service (SMTP) instead of using the default LeadConnector Email System. This is useful if you already have an established sending reputation, need higher volume limits, or prefer to manage your own email infrastructure.

This guide walks you through adding, configuring, and activating a custom SMTP service inside your sub-account.

Video Walkthrough
1

Where to Find Email Services

Navigate to the Email Services settings using the steps below:

  1. Log in to your sub-account
  2. Click Settings in the left sidebar
  3. Select Email Services
  4. Go to the SMTP Service tab (or Advanced Settings depending on your interface version)
Tip

Your interface may show tabs labeled 'SMTP Service' or 'Advanced Settings' — both lead to the same SMTP configuration area.

2

Default vs. Custom Email Service

A side-by-side comparison to help you decide which option fits your business:

LeadConnector (Default)Custom SMTP (Third-Party)
Managed by the platformManaged by you / your provider
Full access to all built-in deliverability toolsSome built-in tools are unavailable (see limitations)
No extra setup requiredRequires SMTP credentials from your provider
Recommended for most usersBest for users with existing sending infrastructure
3

Supported SMTP Providers

When you click + Add Service, you can choose from the following providers:

Gmail — Google Workspace or personal Gmail
Yahoo Mail
SendGrid
Other — covers Mailgun, Amazon SES, Postmark, Zoho, and any SMTP-compatible service
Setup Guide
Adding a Custom SMTP Service
Follow these five steps to connect your third-party email service.
4

Step-by-Step: Adding a Custom SMTP Service

Step 1
Open Email Services

Go to Settings → Email Services → SMTP Service tab.

Step 2
Click + Add Service

In the top-right corner of the page, click the + Add Service button. A popup will appear titled 'Add your own email service'.

Click Add Service to open the SMTP setup popup
Step 3
Select Your SMTP Provider

From the SMTP Provider dropdown, select your provider:

  • Gmail
  • Yahoo Mail
  • SendGrid
  • Other (for Mailgun, Amazon SES, Postmark, etc.)
Choose your SMTP provider from the dropdown
Step 4
Enter Your SMTP Credentials

Fill in the required fields. These details come from your email provider's dashboard:

FieldDescription
SMTP HostThe outgoing mail server address (e.g., smtp.sendgrid.net)
PortUsually 587 (TLS) or 465 (SSL)
UsernameYour SMTP login username or API key identifier
Password / API KeyYour SMTP password or API key from the provider
From NameThe display name that recipients will see
From EmailThe email address emails will be sent from
Fill in your SMTP credentials
Step 5
Save and Set as Active

Once saved, your new SMTP service will appear in the provider list. To start using it:

  1. Find your newly added service in the list
  2. Click Set as active
  3. Confirm the selection
Tip

You can have multiple SMTP services saved and switch between them at any time. Only one can be active at a time.

5

Common SMTP Settings Reference

Quick reference for popular providers — verify values in your provider's dashboard before pasting.

ProviderSMTP HostPortNotes
Gmailsmtp.gmail.com587 / 465Requires App Password if 2FA is on
SendGridsmtp.sendgrid.net587Use 'apikey' as username
Mailgunsmtp.mailgun.org587Use your Mailgun SMTP credentials
Amazon SESemail-smtp.[region].amazonaws.com587Requires IAM SMTP credentials
Postmarksmtp.postmarkapp.com587Use server API token as credentials
Yahoo Mailsmtp.mail.yahoo.com587Requires app password
Zoho Mailsmtp.zoho.com587Use your Zoho account credentials
6

Important: Limitations of Third-Party SMTP

When you use a custom SMTP service instead of LeadConnector, some platform features become unavailable. Please review these limitations before switching:

Features NOT available with third-party SMTP
  • Create dedicated sending domain from the app
  • Google Postmaster tools integration
  • Microsoft Postmaster tools integration
  • Risk Assessment
  • Bounce Classification
  • Inbox Placement Testing
  • Spam Score Checker
  • Blacklist Monitor
  • Managed Domains & IPs
Important

If these features are important to your email strategy, consider staying on the LeadConnector Email System, which gives you full access to all built-in deliverability tools.

7

Enable Reply for SMTP

When viewing your active SMTP service, you will see an Enable reply checkbox. Enabling this allows inbound replies to emails sent through your SMTP to be received and tracked inside platform conversations.

Tip

If you need two-way email communication with your contacts, make sure Enable reply is checked for your active SMTP service.

8

Switching Back to LeadConnector

You can switch back to the default LeadConnector Email System at any time:

  1. Go to Settings → Email Services → SMTP Service
  2. Click on LeadConnector Email System
  3. Click Set as active (or select it as the default)
Good to Know

All your custom SMTP services will remain saved and can be reactivated later.

9

Frequently Asked Questions

Q: Can I have multiple SMTP services saved?
Yes. You can save as many SMTP services as you like. However, only one can be active at a time for outgoing emails.
Q: Will my contacts see the SMTP provider details?
No. Contacts only see the From Name and From Email you configure — not the underlying SMTP provider details.
Q: What happens to emails already sent if I switch providers?
Switching providers only affects future emails. Previously sent emails are not affected.
Q: My SMTP connection is failing — what should I check?
  • Verify that the SMTP host, port, username, and password are correct
  • Make sure port 587 or 465 is not blocked by your email provider
  • For Gmail, ensure you are using an App Password (not your regular login password) if 2-Step Verification is enabled
  • For SendGrid, ensure your sending domain is verified in your SendGrid account
  • Check that your sending email address is authorized within your SMTP provider's account
Q: Does using custom SMTP affect my built-in email deliverability tools?
Yes. Several built-in deliverability tools (Postmaster integrations, Risk Assessment, Bounce Classification, Inbox Placement, Spam Score Checker, Blacklist Monitor, and Managed Domains/IPs) become unavailable when you switch to a third-party SMTP. Refer to the limitations section above.
Q: Which SMTP port should I use — 587 or 465?
Use 587 with TLS (recommended by most modern providers) and 465 with SSL. If one port is blocked by your network, try the other.
Q: Will replies to my emails come back into the platform?
Only if you check the Enable reply option on your active SMTP service. With this enabled, inbound replies are received and tracked inside platform conversations.