Productivity

Plug in to any outreach stack. No lock-in.

Standard SMTP relay and IMAP access keys connect seamlessly with Instantly, Smartlead, Lemlist, Apollo, Clay, or your own custom scripts.

Generate SMTP Key View Pricing

app.coldmailserver.com

SMTP & IMAP Access KeysActive

Primary integration key

Host:smtp.coldmailserver.comUsername:smtp_user_01@outbound.comPassword:••••••••••••••••••••••••

Mailbox SMTP credentials manager

Integrate using secure SMTP and IMAP protocols

Many email providers force you into proprietary APIs or restrict SMTP access to prevent high-volume sending. This locks you into specific tools or increases custom development complexity.

Cold Mail Server is built on open standards. We support standard TLS/SSL connections, making it straightforward to connect to any outreach tool on the market or trigger sequences via custom code.

You can generate unique credentials for each sending mailbox, allowing you to revoke access keys individually without disrupting your entire setup.

app.coldmailserver.com

const nodemailer = require("nodemailer");

const transporter = nodemailer.createTransport({
host: "smtp.coldmailserver.com",
port: 465,
secure: true,
auth: {
user: "smtp_user_01@outbound.com",
pass: process.env.CMS_SMTP_KEY
}
});

Standard Node.js SMTP connection script

Compatibility

Plugs natively into your outreach tools

Instantly.ai

Automated multi-mailbox campaigns with warmup syncing.

Smartlead.ai

Enterprise scale outreach, rotation, and sub-inbox management.

Lemlist

Multichannel sequences with personalized variables.

Clay.com

Enrich leads and trigger outbound mails directly via SMTP integration.

Apollo.io

Scale sequences directly using custom SMTP routing protocols.

Custom Scripts

Connect NodeJS, Python, Go, or PHP scripts directly via SMTP keys.

Technical Specifications

SMTP & IMAP protocol ports

Connection Parameter	Port	Security Protocol	Authentication type
SMTP Relay (SSL/TLS)	465	SSL / TLS	AUTH PLAIN / LOGIN
SMTP Relay (STARTTLS)	587	STARTTLS	AUTH PLAIN / LOGIN
IMAP Access (SSL/TLS)	993	SSL / TLS	AUTH PLAIN / LOGIN
IMAP Access (STARTTLS)	143	STARTTLS	AUTH PLAIN / LOGIN

SMTP & IMAP FAQs

Can I connect custom Python or NodeJS scripts?

Yes. Because we expose standard SMTP ports, you can use standard libraries (like Nodemailer in JS or smtplib in Python) to relay outgoing mail from your apps.

Is IMAP secure?

Yes. All IMAP connections enforce SSL/TLS encryption protocols, ensuring secure retrieval of mailbox reply threads.

How do I generate credentials?

From your dashboard, verify your domain, create a mailbox, and click 'Generate SMTP Key' to instantly configure connection access values.

Are there concurrency limits?

Agency and Scale plans support up to 50 concurrent SMTP connections to allow rapid campaign execution queues.

0.00%Relay Port Connection Uptime

< 0msSMTP Response Time

0%Standard Protocol Compliance

Connect your outbound tools today

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