How to send cold email from your own Gmail or SMTP mailbox

Why send cold email from your own mailbox?

When campaigns go out from your own mailbox, the recipient sees your real name and address, and any reply lands straight in the inbox you already read. There is no separate sending address to monitor, and the conversation continues in your normal email. It also keeps you honest about volume: a real mailbox has real limits, which is a good thing for deliverability.

LeadFinder campaigns always send from your own mailbox, on Pro (1 sending mailbox) and Premium (3 sending mailboxes). The Free plan does not include campaigns. A campaign sends one email to each recipient. There are two ways to connect a mailbox.

Option 1: How does one-click Gmail work?

If you use Gmail or Google Workspace, connect it in one click from LeadFinder. You sign in with Google and grant send-only access, which lets LeadFinder send your campaign emails but not read your inbox.

Because the connection is send-only, LeadFinder cannot see replies in a one-click Gmail mailbox. Replies arrive in your Gmail as normal. When someone answers, open the campaign's review screen and click Mark as replied on the email you sent them. That stops any other queued campaign emails to that person.

Option 2: How do you connect any mailbox over SMTP?

SMTP is the standard way email apps send mail through your provider's server. You give LeadFinder the server settings and password for your mailbox, and campaign emails go out from your address as if you had sent them from your mail app. The setup takes a few minutes:

1. Get an app password first if your provider needs one (for example Gmail, or Zoho with two-factor authentication on).
2. In LeadFinder, go to Campaigns → Sending mailboxes and choose Other email (SMTP).
3. Pick your provider to fill in the servers automatically, or enter them manually.
4. Enter the email address you will send from and, optionally, a sender name such as "Priya from Acme".
5. Check the SMTP server, port and security, username and password or app password.
6. Leave Detect replies and bounces (IMAP, read-only) ticked if your provider supports it. LeadFinder then checks for replies in the background and stops queued emails to anyone who has replied.
7. Click Test and connect. LeadFinder logs in to check the details before anything is saved, and nothing is sent.

Settings for common providers, from the setup guide:

Gmail over SMTP is the way to get automatic reply detection on Gmail. It needs 2-Step Verification on the Google account and an App Password, and some Google Workspace admins block app passwords.

For Microsoft 365, your admin must turn on Authenticated SMTP (SMTP AUTH) for your mailbox. The guide notes that Microsoft is switching this off by default at the end of December 2026, and admins can turn it back on. The Microsoft 365 preset has no IMAP, so reply detection is off.

What if the connection fails?

• Authentication failed (535, "invalid credentials"). Use an app password instead of your normal password, and use your full email address as the username. On Microsoft 365, ask your admin to enable SMTP AUTH.
• Timed out or "wrong version number". The port and security do not match. Port 465 goes with SSL/TLS and port 587 with STARTTLS.
• Relaying disallowed. The from address must be the mailbox you log in with, or an alias it is allowed to send as.
• IMAP fails but SMTP works. Turn on IMAP access in your mailbox settings, or untick reply detection.

What are sending safety limits, and why do they matter?

Every email provider limits how much one mailbox can send each day and blocks sending for a while if you go over. Hitting that wall in the middle of a campaign is bad for you and for your mailbox's reputation. LeadFinder's built-in safety limits keep you well below those caps. These are the defaults:

• Daily limit: 50 emails per mailbox. You can raise it to 100 on Pro and 200 on Premium.
• Warm-up: a new mailbox starts at 20 emails a day and adds 5 a day until it reaches your daily limit.
• Spacing: a random gap of 90 to 300 seconds between emails, so sending looks like a person, not a blast.
• Send window: 9:00 to 18:00, Monday to Friday, and you can adjust it. There is no separate hourly cap.
• Auto-pause: sending pauses automatically on any spam complaint, or when bounces go above 5% after at least 20 sends.

Your plan also sets how many campaign emails you can send a month: 2,000 on Pro and 10,000 on Premium. Check your provider's own limits before you raise the daily limit.

What happens when someone replies?

A campaign sends one email to each recipient. When a recipient replies, LeadFinder stops any other queued campaign emails to that person, so nobody who has already answered gets another email from your campaigns. How LeadFinder learns about the reply depends on the mailbox:

• SMTP mailbox with reply detection on: LeadFinder reads replies over IMAP (read-only) in the background and stops queued emails automatically. Because it is a background check, it is not instant.
• One-click Gmail, or any SMTP mailbox with reply detection off (including the Microsoft 365 preset): open the campaign's review screen and click Mark as replied on the sent email.

Worked example: a campaign to Toronto dentists

Priya runs a small agency on Pro and has saved Toronto dentists with an email to a list (see how that list was built). She connects her work mailbox over SMTP with reply detection on, sets her sender name to "Priya from Acme" and keeps the default limits. Her campaign sends one short email to each clinic. Because the mailbox is new, warm-up starts her at 20 emails a day and adds 5 a day up to her daily limit of 50, with a random 90 to 300 second gap between emails, during weekday working hours. When a clinic replies, LeadFinder picks up the reply in the background and stops any other queued campaign emails to that clinic. Had she connected Gmail in one click instead, she would click Mark as replied on each answered email in the campaign's review screen.

What should every cold email include?

• Who you are and the business you represent, with a real sender name.
• Why you are writing to this business specifically, in one line.
• One clear offer or question.
• An easy way to say no or opt out, and respect it when someone does.