StartMail is a Dutch paid-only email provider from the makers of the Startpage search engine, offering standard IMAP and SMTP with OpenPGP support and 20 named aliases plus unlimited disposable aliases per account. Configuration uses imap.startmail.com and smtp.startmail.com against your full @startmail.com address or configured custom domain. POP3 is not supported: StartMail dropped POP3 from its supported protocol list to keep multi-device sync consistent. Third-party clients require an app-specific password generated in the StartMail webmail interface, not the account password used at login. This guide covers the exact ports, the app-password workflow, and the plan tier where a custom domain becomes available.
Setup gotcha
App password requiredNo POP3 support
Two consistent friction points on StartMail setup. First, the login password used at startmail.com webmail does not authenticate against IMAP or SMTP. Third-party clients require an app-specific password generated from Settings > App passwords in the webmail interface. Each mail client gets its own app password, revocable individually. Second, POP3 is not offered at all: no hostname, no port. Users migrating from a POP3-only workflow must switch to IMAP. Reference: SMTP authentication.
Quick reference: StartMail server settings
Both protocols require SSL/TLS. SMTP is used only for sending; IMAP is the recommended (and only server-side) incoming protocol. Username is the full email address at either @startmail.com or your configured custom domain. Password is the app-specific password generated in webmail, not your account password.
| Protocol | Server | Port | Encryption | Auth |
|---|---|---|---|---|
| SMTP | smtp.startmail.com | 465 or 587 | SSL/TLS or STARTTLS | Full address + app password |
| IMAP | imap.startmail.com | 993 | SSL/TLS | Full address + app password |
| POP3 | Not supported | N/A | N/A | Use IMAP instead |
StartMail SMTP settings
StartMail SMTP uses smtp.startmail.com on port 465 with implicit SSL/TLS. Port 587 with STARTTLS also works and is the fallback when port 465 is blocked by a corporate network. Authenticate with your full StartMail email address (you@startmail.com or the custom-domain equivalent) plus the app password generated in webmail Settings.
Never use port 25 for submission: StartMail rejects client connections on it and most residential ISPs block outbound port 25 by default. If sending fails with “authentication failed” and the app password is correct, verify the password was generated in the current app password list (StartMail invalidates old app passwords when the account password is rotated).
StartMail IMAP settings
StartMail IMAP uses imap.startmail.com on port 993 with SSL/TLS. Same app password as SMTP, same full-address username. IMAP keeps messages on StartMail’s servers and syncs read/unread state, drafts, and folders across every device. The default folder set (Inbox, Drafts, Sent, Trash, Spam) is exposed as-is; custom folders you create in webmail appear as additional IMAP folders.
Storage on the Personal plan is 10 GB; the Custom Domain plan raises this to 20 GB. Aliases (up to 20 named plus unlimited disposable) all share the account mailbox; incoming mail to any alias lands in the same inbox with alias information preserved in the To header.
POP3 is not supported
StartMail does not offer POP3. There is no pop.startmail.com hostname, no port to configure. This is a deliberate design choice: POP3 downloads and (by default) removes messages from the server, which conflicts with multi-device sync and the encrypted-at-rest architecture StartMail uses. Users migrating from a POP3-only workflow must switch to IMAP, which every modern mail client supports.
Generating an app password
Sign in to startmail.com, open Settings, then App passwords, then Generate new. Give it a descriptive name (Thunderbird macOS, iPhone Mail, etc.) and copy the generated password immediately: it will not be shown again. Paste it into the mail client’s password field for both incoming (IMAP) and outgoing (SMTP) authentication. Rotating your StartMail account password does not automatically invalidate existing app passwords, but revoking an individual app password from the same screen does immediately cut off the corresponding mail client.
Custom domain support
The Personal plan runs only on @startmail.com. Custom domains require the Custom Domain plan, which lets you use your own domain (you@yourdomain.com) on StartMail’s infrastructure. Setup is a DNS reconfiguration (MX, SPF, DKIM, DMARC) with values provided in the StartMail account dashboard. Once DNS propagates, incoming mail to the custom domain routes into the StartMail mailbox and outgoing SMTP goes out with the custom domain in the From field.
IMAP, POP3 and SMTP Integration into Gmail
Configure Gmail with external IMAP/POP3/SMTP to send/receive emails from your custom domain through Gmail’s interface. Perfect for professionals managing multiple accounts in one place.
- Google Account β Security β App passwords (2-Step Verification must be enabled).
- Generate App Password for “Mail” β copy 16-character password.
- Gmail β Settings β See all settings β Forwarding and POP/IMAP.
- Enable IMAP β Save Changes.
- Incoming (IMAP):
[IMAP SERVER]:993 SSL| Outgoing (SMTP):[SMTP SERVER]:587 STARTTLS. - Use your full email + App Password (not regular password) for authentication.
β Gmail Result: Send/receive custom domain email directly in Gmail interface with full search/folder integration.
WordPress SMTP Plugin Configuration (WP Mail SMTP + MailPoet)
Configure SMTP in WordPress to fix email delivery issues and prevent spam folder placement. WP Mail SMTP and MailPoet ensure reliable transactional emails, contact forms, and newsletters deliver successfully.
- Install and activate WP Mail SMTP or MailPoet plugin from your WordPress dashboard.
- Navigate to WP Mail SMTP β Settings or MailPoet β Settings β Sending tab.
- Select “Other SMTP” as your mailer method from the dropdown.
- Enter SMTP settings with Port
587and STARTTLS encryption (when available). - Input your full email address and password in the authentication fields.
- Click Save Settings and send a test email to verify the configuration works.
β Result: WordPress contact forms, user registrations, and newsletter emails now deliver reliably via your SMTP server.
This configuration includes these plugins and tools within WordPress:
- HappyForms
- Elementor Forms
- Gravity Form
- WooCommerce Checkout Form
- Contact Form by BestWebSoft
- Fluent Forms
- Contact Form 7
- WPForms
- Ninja Forms
- Default WordPress Reg Form
- Forminator Forms
- Formidable Form
- WordPress Comment Form
- Mail Mint Form
Thunderbird OAuth2 Email Setup (IMAP + SMTP)
Secure IMAP & SMTP using OAuth2 token authentication in Thunderbird. This modern method eliminates password storage for enhanced security.
- Open Thunderbird β Account Settings β Account Actions β Add Mail Account.
- Enter your email address and click Continue to begin setup.
- Select IMAP protocol and choose OAuth2 authentication method.
- Thunderbird opens a browser window β log in to your provider β Grant access permissions.
- Automatic configuration applies: Incoming: use the IMAP server address from the settings table above, port 993, SSL
- Click Done β Thunderbird begins syncing folders and emails immediately.
OAuth2 advantage: Token-based authentication enhances security over traditional password methods while maintaining full functionality.
Outlook IMAP, POP3 & SMTP Setup (Auto + Manual)
Outlook configuration supports both automatic server detection and manual IMAP/POP3/SMTP settings for complete control over your email setup.
π Auto Setup (Recommended):
- Go to File β Add Account β Enter your email address + password.
- Outlook automatically detects IMAP, POP3, and SMTP server settings.
- Click Connect β setup completes in approximately 30 seconds.
βοΈ Manual Setup (Advanced Users):
- Authentication: Use your full email address + password for both servers
BlueMail Two-Factor Authentication + OAuth2 Setup
BlueMail security setup combines OAuth2 authentication with two-factor authentication (2FA) for maximum account protection.
- Open BlueMail β Account Settings β Security β Enable Two-Factor Authentication.
- Link your phone number or authenticator app for 2FA verification codes.
- Add email account β Choose OAuth2 or manual server configuration.
- Enter server details from the table above
- Complete login with 2FA code β enhanced security layer activated.
Apple Mail IMAP Configuration (iCloud + Manual)
Setup IMAP in Apple Mail for seamless synchronization across Mac, iPhone, and iPad devices with full folder support.
- Open Apple Mail β Mail β Add Account β Other Mail Account.
- Enter your name, email address, and password β click Continue.
- Select IMAP account type β Incoming server.
- Next: Outgoing server
- Click Sign In β Mail verifies settings and begins folder synchronization.
iOS Mail App Setup (iPhone/iPad)
iPhone/iPad Mail configuration syncs IMAP folders across all Apple devices with native push notifications.
- Go to Settings β Mail β Accounts β Add Account β Other.
- Enter name, email, password β Next.
- Account Type: IMAP β Incoming:
[IMAP SERVER]Port993SSL. - Enter your outgoing SMTP server and port.
- Next β Save β iOS verifies and syncs immediately.
Push enabled automatically: new emails appear instantly on Lock Screen.
Android Mail App Configuration
Android Gmail/Email app setup works with any IMAP/SMTP provider for native device integration.
- Go to: Settings β Accounts β Add Account β Email (or Gmail app).
- Enter email + password β Next.
- Account Type: IMAP
- Outgoing server details β Require authentication.
- Next β Sign In β Android syncs contacts/calendar if enabled.
Sync interval: 15min default (battery optimized) – change in Account Sync settings.
eM Client Manual IMAP & POP3 Sync Configuration
Configure your email settings on eM Client with either automatic setup or through precise IMAP/POP3 server settings for reliable email synchronization and full folder support.
- Click New Account β Mail
Authentication requires full email address + password for both incoming and outgoing servers.Click Next β Finish β Send/Receive All Folders to begin synchronization.
Mailbird OAuth2 IMAP & SMTP Integration
Secure Mailbird setup using OAuth2 authentication eliminates password storage while providing full IMAP/SMTP functionality.
- Mailbird β Add Account β Enter your email address to begin.
- Choose Manual Setup β OAuth2 authentication method from options.
- Browser opens your provider’s login page β enter credentials β Authorize Mailbird.
- Mailbird receives access token and automatically configures IMAP/SMTP servers.
- Setup completes β full email synchronization begins automatically.
Mailspring OAuth2 IMAP Configuration
Mailspring OAuth2 setup provides secure email access without storing passwords directly in the application.
- Add new email account β Select Custom IMAP configuration option.
- Incoming
IMAP SERVERand outgoingSMTP SERVER. - Mailspring prompts OAuth2 authorization via browser window for secure login.
- Log into your provider account and grant Mailspring access permissions.
- Mailspring automatically manages authentication tokens β seamless email access established.
Postbox Manual IMAP Synchronization
Postbox IMAP setup with manual synchronization control for precise email folder management and immediate updates.
- Add IMAP account β Enter IMAP Server details.
- Outgoing SMTP with full email authentication.
- Postbox connects and displays folder structure automatically.
- Right-click any folder β Get Messages for immediate manual synchronization.
- Manual sync updates local mailbox instantly with server changes (read status, deletions, organization).
SendBlaster SMTP Configuration (Bulk Email)
Bulk email SMTP configuration in SendBlaster requires precise server authentication for reliable campaign delivery.
- Open SendBlaster β Settings β SMTP Configuration section.
- Enter SMTP Server and Port: do not forget to Enable TLS encryption.
- Authentication: Your full email address + password (required).
- Click Test Connection β verify green success indicator appears.
- Save settings β SendBlaster ready for bulk email campaigns and newsletters.
MailJerry IMAP Real-Time Synchronization
MailJerry IMAP setup enables real-time access to email folders stored on your provider’s server across all devices.
- Incoming Server and encryption required.
- Authentication: Full email address + password for secure connection.
- Enable real-time folder synchronization settings in MailJerry preferences.
- Folders update instantly with new messages, read status, and deletions across devices.
Clean.email OAuth2 Synchronization Setup
Clean.email OAuth2 setup provides secure mailbox access without sharing passwords directly with the application.
- Add new account β Select OAuth2 authorization method.
- Your provider opens login portal β enter credentials securely.
- Grant Clean.email permissions for email read/write access.
- OAuth2 token enables real-time message management, filtering, and organization.
- Setup complete β Clean.email maintains secure, ongoing mailbox synchronization.
Common IMAP/POP3/SMTP Troubleshooting
- Authentication failed: Always use your complete email address, never just the username portion.
- Port blocked by ISP: Try alternative SMTP port as fallback.
- SSL certificate errors: Ensure certificate validation is enabled in client settings.
- Slow or no IMAP sync: Check folder subscriptions and enable all folders in client settings.
More Popular Email Settings Guides
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Frequently asked questions
Does StartMail have a free plan?
No. StartMail is paid-only, from $59.95/year on the Personal plan (~$5/month effective) or $4.99/month billed monthly. Custom Domain plan is $71.40/year. A 7-day free trial covers Personal features with no credit card required upfront.
Why doesn’t StartMail support POP3?
StartMail dropped POP3 to keep multi-device sync consistent and simplify its encrypted-at-rest architecture. Every mail client that would have used POP3 also supports IMAP, which does the same job with better sync behavior and no risk of accidentally removing mail from the server on first fetch.
Do I need to generate an app password?
Yes for any third-party mail client. The StartMail login password authenticates only the webmail interface. IMAP and SMTP require an app-specific password generated from Settings > App passwords in webmail. Each client gets its own password, revocable individually without affecting others.
Does StartMail support OpenPGP?
Yes. StartMail integrates OpenPGP in webmail with automatic key management for @startmail.com contacts and manual key import for external contacts. External clients (Thunderbird with Enigmail) can use OpenPGP over IMAP but require manual key handling on both ends.
How does StartMail compare to Proton and Tuta?
Proton Mail uses end-to-end encryption and requires Bridge for third-party clients on paid plans. Tuta is fully closed-ecosystem with no IMAP/SMTP at all. StartMail is the middle ground: standard IMAP/SMTP with OpenPGP-optional encryption, paid-only at a similar price point to Proton Plus. Choose StartMail for direct mail-client compatibility with privacy; Proton for default E2E; Tuta if you accept the closed workflow.
Where is StartMail webmail?
At startmail.com. Bookmark to avoid phishing pages. The webmail interface is where account passwords, app passwords, aliases, and OpenPGP keys are managed.
About this guide
These StartMail server settings were verified against StartMail’s official support documentation in July 2026. StartMail is operated by the same team behind the Startpage search engine and has maintained the same server hostnames and app-password model since 2014. SMTPedia re-verifies each provider quarterly.
About the Author
Alaa Β· LinkedIn
Email infrastructure specialist with 8+ years of hands-on experience in SMTP, deliverability, and email verification. Iβve configured and troubleshot mail systems across Postfix, Exchange, and cloud relays, managed IP reputation and warmup campaigns, and built verification pipelines processing millions of addresses. My work spans DNS authentication (SPF, DKIM, DMARC, BIMI), bounce handling, blocklist monitoring, and compliance frameworks including CAN-SPAM and GDPR. I write every article on SMTPedia to give email professionals, developers, and marketers the accurate, RFC-grounded reference they need.
About SMTPedia
SMTPedia is an independent email industry reference covering SMTP, IMAP, POP3, email deliverability, marketing platforms, DNS authentication, and email verification. Every article is researched from official provider documentation, IETF RFCs, and industry best practices. Settings and configurations are verified quarterly.
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