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Warmy — Email Sending Process

How warm-up emails are actually sent

Overview

Warmy is an email warm-up automation platform. Its core job is to gradually build a positive sender reputation for a user's email domain and IP address by simulating real, human-like email activity. To do this, Warmy needs to send and receive emails on behalf of the user — and the way it does this depends on how the mailbox is connected.

There are two distinct connection methods in Warmy, and a separate receiving mechanism (Warmy Network). It is critical to understand all of them:

  1. SMTP/IMAP Connection
    Warmy sends warm-up emails through the user's own mail server using the credentials the user provides (SMTP host, port, username, password).
  2. OAuth Connection (Google Workspace & Microsoft)
    Users connect Google Workspace or Microsoft 365 by signing in through Google's or Microsoft's official authentication screen. No SMTP/IMAP credentials are required. Note: standard Gmail accounts connect via App Password, not OAuth.

Warmy Network (Separate Mechanism)

The Warmy Network / Seed Network is not a connection type — it is the mechanism by which warm-up emails are received and engaged with. Warm-up emails are exchanged between real accounts inside Warmy's own pool of mailboxes. This is covered in Section 2.

1. How Warmy Sends Emails via SMTP/IMAP

What happens when a user connects their mailbox

When a user connects a mailbox to Warmy using SMTP and IMAP credentials, Warmy uses those credentials to authenticate directly with the user's mail server. Warmy then sends warm-up emails through that server — the same way an email client like Outlook or Thunderbird would.

The sending path is straightforward:

Warmy Platform (Automation Engine) → User's Mail Server (via user's SMTP credentials) → Warm-up Email Delivered (to network accounts or seed list)

Warmy's Own Servers

Warmy uses its own servers/IPs only for connection purposes (EMS). All warm-up emails are sent through the user's own mail server — Warmy does not operate a separate sending MTA or IP for warm-up delivery.

Important: Warmy does NOT use its own servers to send warm-up emails via SMTP connection. Warmy acts as an automation layer that logs into the user's mail server and triggers sends from there. Warmy has no separate IP or MTA that delivers warm-up emails on the user's behalf.

What SMTP is used for

SMTP (Simple Mail Transfer Protocol) is the protocol Warmy uses to send warm-up emails. When the user provides their SMTP credentials, Warmy connects to the user's outgoing mail server and sends emails through it. This means:

  • All warm-up emails originate from the user's own mail server
  • The sending IP address belongs to the user's server, not Warmy
  • The email is signed with the user's domain — SPF and DKIM pass as normal
  • Activity will appear in the user's mail server logs — this is expected and correct

What IMAP is used for

IMAP (Internet Message Access Protocol) is used separately — for reading and managing incoming mail. Warmy uses IMAP to:

  • Read warm-up reply emails that arrive in the user's inbox
  • Move emails out of the spam folder and mark them as important (positive engagement signals)
  • Simulate natural inbox activity to make the warm-up behaviour appear human to ISPs

Note: IMAP is never used for sending. It is receive/read-only access.

SMTP Configuration Fields

When connecting via SMTP, users are asked to provide:

  • Email address — the mailbox being warmed up
  • Send-from name — display name shown to recipients
  • SMTP host — the outgoing mail server address (e.g. smtp.ionos.com)
  • SMTP port — 587 or 465 for secure (TLS/SSL). Port 25 is not supported
  • SMTP username — usually the email address; used to authenticate with the server
  • SMTP password — password for SMTP authentication (or App Password for Gmail/Yahoo)
  • IMAP host — the incoming mail server (e.g. imap.ionos.com)
  • IMAP port — 993 (secure) or 143 (unsecured)
  • IMAP username/password — used to access the inbox to read replies and manage engagement

1b. Connecting via OAuth (Google Workspace & Microsoft)

Google Workspace and Microsoft Outlook / Office 365 users can connect their mailbox to Warmy using OAuth instead of providing SMTP and IMAP credentials manually. OAuth is the recommended connection method for these providers as it is more secure and easier to set up.

Gmail vs Google Workspace:
OAuth is supported for Google Workspace accounts. Standard Gmail accounts connect via App Password (not OAuth). For Microsoft, OAuth works for both personal Outlook and Microsoft 365 / Office 365 accounts. Domain-wide delegation is also available for both Google Workspace and MS 365.

Google Workspace OAuth

To connect Google Workspace via Google OAuth:

  1. In the Warmy dashboard, select "Connect with Google" when adding a new mailbox
  2. The user is redirected to Google's consent screen and signs in with their Google Workspace account
  3. The user grants Warmy the required permissions
  4. Warmy receives a secure OAuth access token and refresh token. No password is stored
  5. Warmy uses the Gmail API to send warm-up emails and manage inbox engagement

Microsoft OAuth (Outlook / Office 365)

To connect Outlook or Microsoft 365 via Microsoft OAuth:

  1. Select "Connect with Microsoft"
  2. Sign in via Microsoft login
  3. Grant required permissions (Mail.Send, Mail.ReadWrite, etc.)
  4. Warmy stores OAuth tokens
  5. Warmy uses Microsoft Graph API

Key Benefits of OAuth

  • No password is ever shared
  • Tokens can be revoked anytime
  • Simpler setup
  • No SMTP configuration needed
  • No need to enable SMTP AUTH for Microsoft

2. The Warmy Warm-Up Network (Who Receives the Emails)

The peer network

Once Warmy sends a warm-up email (via the user’s SMTP server or through API/OAuth), it needs to land in a realistic environment to properly simulate real email interactions. Warmy maintains a large engagement network made up primarily of its own managed mailboxes, along with a smaller portion of accounts belonging to Warmy users. Warm-up emails are exchanged within this network, helping generate authentic sending, receiving, and engagement signals that improve deliverability.

When a warm-up email arrives in a network account's inbox, Warmy automatically:

  • Opens the email (simulating genuine reading behaviour). Note: scrolling applies to seed list mode; auto warm-up does not scroll
  • Clicks links at natural, randomised intervals (seed list mode only; not used in auto warm-up unless purchased Warm-up with clicks feature)
  • Replies with contextually appropriate responses (applies only to regular automated warm-up plans, not Seed Lists)
  • Marks emails as Important consistently to strengthen engagement signals
  • Moves it out of spam if it was filtered there, and marks it Not Spam

Why this matters

These positive engagement signals — opens, replies, inbox rescues — train ISPs (Gmail, Outlook, Yahoo, etc.) to recognise the sending domain as legitimate and trustworthy. This is the core mechanism by which Warmy improves deliverability.

Email content in the warm-up network

Warm-up emails sent through the network are not generic spam-like content. Warmy generates realistic, business-appropriate email content tailored to:

  • The user's industry or topic (for example SaaS, e-commerce, legal)
  • The selected language (more than 30 languages supported)
  • Whether the audience is B2B or B2C

Users can also add their own email templates to the warm-up process. Warmy will not only test them for deliverability but also actively use them during warm-up interactions. The share of these custom templates can be adjusted as needed and may reach up to 100% of the warm-up traffic.

3. Seed List — Alternative Path for Non-Integrated Platforms

What is the Seed List

The Seed List is a separate Warmy product for users who cannot directly connect their mailbox to Warmy (for example Mailchimp, Klaviyo, HubSpot, or another platform that Warmy does not natively integrate with).

Instead of Warmy sending through SMTP, the process works differently:

  1. The user downloads a CSV of seed email addresses from Warmy (60,000+ addresses, real Gmail, Outlook, Yahoo and GSuite accounts)
  2. The user uploads that CSV to their own email platform and sends their campaign to those addresses
  3. Warmy's AI automatically opens, clicks, scrolls, marks as important, and rescues from spam any emails received at those seed addresses
  4. This generates positive engagement signals without requiring direct access to the user’s SMTP credentials

It is also ideal for platforms Warmy does not natively integrate with.

SMTP warm-up vs Seed List

SMTP warm-up:
Warmy sends the emails through the user's own server. Engagement is handled via IMAP (replies and inbox management).

Seed List:
The user sends emails themselves via their own platform. Warmy controls only the receiving side. Engagement includes clicks and scroll, which is different from IMAP-based auto warm-up.

Seed List Accounts

The seed accounts are real, active mailboxes (not bots) across Gmail, Outlook, GSuite and Yahoo.

The seed list is rotated regularly, with a major refresh taking place once per month, where a significant portion of the seed list split is updated. Warmy continuously expands and updates its seed list pool by adding new addresses, ensuring a more effective and up-to-date warm-up process.

4. Full Sending Process — Step by Step

SMTP/IMAP warm-up (standard connection)

  1. The user connects a mailbox to Warmy by providing SMTP and IMAP host, port, username, and password
  2. Warmy analyses the mailbox state and creates a personalised warm-up schedule based on the user's plan and sending volume
  3. Each day, Warmy logs into the user's mail server via SMTP and sends a calculated number of warm-up emails to accounts in the Warmy network
  4. Warmy uses IMAP to monitor the user's inbox for incoming replies and engagement signals
  5. Network accounts automatically open, reply to, and engage with the received warm-up emails
  6. The AI tracks the results and adjusts the next day's schedule based on deliverability metrics
  7. Over time (typically 2–8 weeks), ISPs see consistent positive signals and the domain/IP reputation improves

OAuth / API warm-up

For OAuth-connected accounts (Google Workspace, Microsoft 365), the process is identical except Warmy uses the Gmail API or Microsoft Graph API instead of raw SMTP credentials. The warm-up logic, scheduling, and engagement remain the same.

Seed List warm-up (for non-integrated platforms)

  1. The user purchases a Seed List plan and registers their sender email address in Warmy
  2. The user downloads the CSV of seed addresses and uploads it to their email platform
  3. The user sends their campaign to the seed list alongside their regular recipients
  4. Warmy's AI automatically interacts with the emails received at all seed list addresses (opens, clicks, scrolls)
  5. Warmy provides placement reports showing where emails landed (Primary, Promotions, Spam) across providers
  6. The seed list is rotated for the user and Warmy provides new receivers to improve the process

5. Frequently Asked Questions

Does Warmy send emails from its own servers

No. When a mailbox is connected via SMTP, all warm-up emails are sent through the user's own mail server using the credentials provided. Warmy does not have its own sending MTA or IP infrastructure for this purpose. Warmy's role is automation. Its servers and IPs are used only for connection purposes.

Why do I see Warmy in my mail server logs

Because Warmy connects to your mail server using your SMTP credentials and sends emails through it. Every warm-up send is an authenticated SMTP session originating from Warmy's automation platform but relayed entirely through your server. This is expected and confirms the integration is working correctly.

Does Warmy change my SPF or DKIM records

No. Warmy does not modify DNS records. Since emails are sent through your own mail server, SPF and DKIM authentication are handled by your existing setup. No DNS changes are required.

Can Warmy send emails without SMTP access

Yes. There are three ways:

  1. OAuth connection for Google Workspace or Microsoft 365
  2. API-based sending for some providers
  3. Seed List, where Warmy does not send emails and only handles engagement

What IP address is used to send warm-up emails

It depends on the connection method:

  • SMTP: your mail server IP
  • OAuth: Google or Microsoft infrastructure IP
  • API-based: provider infrastructure IP

Who receives the warm-up emails

Warm-up emails are delivered to accounts in Warmy's engagement network. These are real, active mailboxes belonging to other Warmy users across Gmail, Outlook, Yahoo, and other providers. These accounts automatically open, reply, and engage with emails to simulate human behaviour.

What does IMAP access allow Warmy to do

IMAP is used only for receiving. Warmy uses it to read replies, detect spam placement, move emails to inbox, mark them as important, and track engagement. It is never used for sending.

What happens if IMAP credentials are not provided

Warmy can still send emails, but it cannot monitor replies or perform inbox engagement actions. This significantly reduces the effectiveness of the warm-up process.

How does Warmy decide how many emails to send each day

The sending volume depends on the user's plan and sending volume. The AI adjusts the ramp-up automatically based on performance. Users can also choose a warm-up speed: Slow (4–6 weeks), Medium (2–4 weeks), or Fast (1–2 weeks).

Does Warmy warm up both domain reputation and IP reputation

Yes, but only if the user has a dedicated IP. Because warm-up emails are sent through the user's own mail server, both domain reputation and IP reputation are built simultaneously when a dedicated IP is used. On shared IPs, only domain reputation is warmed up.

What mail providers can be connected to Warmy

Warmy supports multiple connection methods:

  • OAuth (recommended): Google Workspace and Microsoft 365 / Outlook can connect via OAuth with no SMTP credentials
  • SMTP/IMAP: any provider that supports SMTP and IMAP can be connected, including Gmail (via App Password), Yahoo, Zoho, IONOS, custom SMTP servers, and others
  • API-based: a small number of providers support API-based sending

For providers not listed in the Warmy interface, users can manually enter SMTP/IMAP host, port, username, and password.

Can I connect Gmail without an App Password

It depends on the account type.

  • Google Workspace accounts can connect via OAuth with no App Password
  • Standard Gmail accounts require an App Password for SMTP/IMAP access
  • OAuth is not available for standard Gmail accounts

6. What Warmy Does NOT Do

Warmy does not:

  • Send marketing or promotional emails
    (Warmy only sends automated warm-up emails within its engagement network. It is not an email marketing platform)
  • Send cold outreach emails
    (Warmy does not send emails to your prospect lists or external contacts)
  • Send emails from its own IPs (SMTP mode)
    (All emails are sent through your mail server using your credentials. Warmy does not provide its own sending infrastructure for SMTP)
  • Modify DNS records (SPF, DKIM, DMARC)
    (Warmy checks DNS settings but does not change them)
  • Store or read your real email content
    (Warmy only interacts with warm-up emails it generates)
  • Guarantee inbox placement
    (Warmy improves sender reputation, but deliverability also depends on content, list quality, and recipient behaviour)
  • Replace proper email authentication setup
    (Warmy requires correct SPF, DKIM, and DMARC configuration)
  • Send emails without user credentials (SMTP mode)
    (SMTP warm-up requires valid credentials. OAuth and Seed List are alternatives)
  • Work as a full deliverability solution for cold email
    (Warm-up improves reputation, but cold email success depends on many external factors)
  • Access data beyond SMTP/IMAP permissions
    (Warmy's access is limited to sending and reading inbox data only)

7. Troubleshooting Common Issues

Authentication failure or cannot connect mailbox

Likely causes:

  • Incorrect SMTP or IMAP credentials
  • Using main password instead of App Password (for Gmail/Yahoo)
  • Incorrect host or port
  • Server blocking third-party access

Resolution:

  • Verify SMTP and IMAP credentials
  • Use App Password for Gmail and Yahoo
  • For Office 365, check SMTP AUTH or use OAuth
  • Use correct ports: 587 (TLS) or 465 (SSL)
  • Ensure IMAP is enabled

Warm-up emails landing in spam

Likely causes:

  • Low sender reputation at the beginning
  • Incorrect authentication setup

Resolution:

  • Verify SPF, DKIM, and DMARC
  • Ensure DKIM is enabled and published
  • Set DMARC to at least p=none
  • Allow time for warm-up
  • Avoid high sending volume early

High bounce rates during warm-up

Likely causes:

  • Misconfiguration
  • Existing reputation issues

Resolution:

  • Check blacklists
  • Verify MX records
  • Confirm SPF configuration
  • Reduce warm-up speed if domain is new

IMAP not connecting or emails not being received

Likely causes:

  • IMAP disabled
  • Incorrect credentials
  • Provider restrictions

Resolution:

  • Enable IMAP in provider settings
  • Verify IMAP host, port, and credentials
  • Use App Password if required
  • Check admin policies for Outlook

Note: without IMAP, warm-up effectiveness is significantly reduced

Warm-up progress is slow or no improvement

Likely causes:

  • Gradual process
  • DNS issues
  • Poor domain reputation
  • Parallel cold email campaigns

Resolution:

  • Confirm daily sending is active
  • Check SPF, DKIM, DMARC
  • Avoid high-volume cold campaigns
  • Check blacklists
  • Use slower warm-up speed if needed

8. Glossary of Key Terms

SMTP
Simple Mail Transfer Protocol. Used to send emails. Warmy uses SMTP to send warm-up emails through your mail server.

IMAP
Internet Message Access Protocol. Used to read and manage emails. Warmy uses it to track replies and engagement.

OAuth
A secure authentication method that allows access without sharing passwords.

App Password
A special password used for third-party access (Gmail, Yahoo).

SMTP relay
Sending emails through an SMTP server as an intermediary.

SPF
A DNS record that defines which IPs can send emails for your domain.

DKIM
A cryptographic signature verifying email authenticity.

DMARC
A policy that defines how failed authentication emails are handled.

Warm-up
Gradual increase of email sending to build reputation.

Sender reputation
A trust score used by email providers.

Engagement network
Warmy’s pool of real email accounts used for warm-up.

Seed list
A list of real email addresses used for engagement when SMTP is not used.

Bounce
An undelivered email (hard or soft).

Blacklist
A list of flagged domains or IPs.

ISP
Email providers such as Gmail, Outlook, Yahoo.

MTA
Mail Transfer Agent, responsible for sending emails. Warmy does not operate its own MTA for warm-up.

TLS / SSL
Encryption protocols used for secure email transmission. Port 587 (TLS) and 465 (SSL) are supported. Port 25 is not supported.

 

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