Frequently Asked Questions
Everything you need to know about Mockmail and how to use it for email testing.
What is Mockmail and how does it work?
Mockmail is a virtual SMTP server service designed for developers to test, debug, and inspect emails safely without sending them to real users.
When you configure your application to use Mockmail's SMTP credentials (host, port, username, password), any emails sent by your app are captured by Mockmail's servers instead of being delivered to actual recipients. You can then view these emails in Mockmail's web interface, where you can:
- Preview HTML and plain text versions
- Inspect headers and raw MIME content
- Download attachments
- Search and filter emails
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Share testing inboxes with your team
This makes it perfect for development, staging, and testing environments where you want to verify that emails are working correctly without the risk of accidentally spamming real users or violating GDPR regulations.
Mockmail is a virtual SMTP server service designed for developers to test, debug, and inspect emails safely without sending them to real users.
When you configure your application to use Mockmail's SMTP credentials (host, port, username, password), any emails sent by your app are captured by Mockmail's servers instead of being delivered to actual recipients. You can then view these emails in Mockmail's web interface, where you can:
- Preview HTML and plain text versions
- Inspect headers and raw MIME content
- Download attachments
- Search and filter emails
- Share testing inboxes with your team
This makes it perfect for development, staging, and testing environments where you want to verify that emails are working correctly without the risk of accidentally spamming real users or violating GDPR regulations.
How does Mockmail capture incoming emails?
Mockmail captures emails through its SMTP server that runs on port 25 (which supports unencrypted and TLS connections). Here's how the process works:
-
Your application connects: When your app sends an email, it connects to Mockmail's SMTP server using the credentials provided in your inbox settings.
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Authentication: Mockmail authenticates the connection using either:
- SMTP username and password (primary method)
- Or by recognizing your inbox's unique email address (e.g., uniquecode@mockmail.io)
-
Email parsing: The SMTP server receives the raw email data and parses it to extract the subject, body (HTML and plain text), sender, recipient, attachments, and all headers.
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Storage: The parsed email is stored in Mockmail's database and made immediately available in the web interface.
-
Real-time notification: Connected users are notified instantly, so you see new emails appear in real-time without refreshing in your testing inbox.
All emails are captured regardless of the recipient address (catch-all functionality), which means you can test password resets, notifications, and any other email flow without worrying about the actual email addresses used in your test data.
Mockmail captures emails through its SMTP server that runs on port 25 (which supports unencrypted and TLS connections). Here's how the process works:
- Your application connects: When your app sends an email, it connects to Mockmail's SMTP server using the credentials provided in your inbox settings.
-
Authentication: Mockmail authenticates the connection using either:
- SMTP username and password (primary method)
- Or by recognizing your inbox's unique email address (e.g., uniquecode@mockmail.io)
- Email parsing: The SMTP server receives the raw email data and parses it to extract the subject, body (HTML and plain text), sender, recipient, attachments, and all headers.
- Storage: The parsed email is stored in Mockmail's database and made immediately available in the web interface.
- Real-time notification: Connected users are notified instantly, so you see new emails appear in real-time without refreshing in your testing inbox.
All emails are captured regardless of the recipient address (catch-all functionality), which means you can test password resets, notifications, and any other email flow without worrying about the actual email addresses used in your test data.
Do I need to change my DNS settings to use Mockmail?
No, you do not need to change any DNS settings to use Mockmail.
Unlike traditional email servers that require MX record configuration, Mockmail uses SMTP authentication to route emails. This means you simply point your application's SMTP configuration directly to Mockmail's server (mockmail.io or smtp.mockmail.io) with your provided credentials.
Here's a typical configuration example:
MAIL_HOST=mockmail.io
MAIL_PORT=25
MAIL_USERNAME=your_unique_username
MAIL_PASSWORD=your_unique_password
MAIL_ENCRYPTION=tls
Mockmail identifies your inbox based on:
- The SMTP username and password you use for authentication, or
- The unique inbox email address if you send emails directly to it
This authentication-based approach means setup is quick and simple—just update your app's SMTP configuration and you're ready to start capturing emails. No DNS changes, no MX records, no SPF/DKIM configuration required.
No, you do not need to change any DNS settings to use Mockmail.
Unlike traditional email servers that require MX record configuration, Mockmail uses SMTP authentication to route emails. This means you simply point your application's SMTP configuration directly to Mockmail's server (mockmail.io or smtp.mockmail.io) with your provided credentials.
Here's a typical configuration example:
MAIL_HOST=mockmail.io
MAIL_PORT=25
MAIL_USERNAME=your_unique_username
MAIL_PASSWORD=your_unique_password
MAIL_ENCRYPTION=tls
Mockmail identifies your inbox based on:
- The SMTP username and password you use for authentication, or
- The unique inbox email address if you send emails directly to it
This authentication-based approach means setup is quick and simple—just update your app's SMTP configuration and you're ready to start capturing emails. No DNS changes, no MX records, no SPF/DKIM configuration required.
Does Mockmail support sending emails?
Mockmail is designed primarily for capturing and receiving emails, but you can forward emails in your Mockmail inbox to different email addresses. This is handy, if you need to quickly share an email with stakeholders during development or testing.
Think of Mockmail as a "catch-all safety net" that sits between your application and the outside world, ensuring no test emails ever escape to real inboxes.
Mockmail is designed primarily for capturing and receiving emails, but you can forward emails in your Mockmail inbox to different email addresses. This is handy, if you need to quickly share an email with stakeholders during development or testing.
Think of Mockmail as a "catch-all safety net" that sits between your application and the outside world, ensuring no test emails ever escape to real inboxes.
How long are captured emails stored?
Each inbox comes with a 50 emails limit. When the limit is reached, the oldest emails are automatically deleted to make room for new ones.
This approach ensures your inbox stays manageable and relevant, automatically clearing out old test data while keeping your most recent emails available for inspection. You can also manually delete emails at any time if you need to clear space or remove sensitive test data.
Each inbox comes with a 50 emails limit. When the limit is reached, the oldest emails are automatically deleted to make room for new ones.
This approach ensures your inbox stays manageable and relevant, automatically clearing out old test data while keeping your most recent emails available for inspection. You can also manually delete emails at any time if you need to clear space or remove sensitive test data.
Can I share a Mockmail inbox with my team?
Yes! Mockmail is built for team collaboration. You can easily share inboxes with your colleagues and control their access levels.
Team collaboration features include:
- Shared inboxes: Create dedicated inboxes that multiple team members can access simultaneously
- Team invitations: Invite colleagues to specific inboxes via email
- Role-based access control: Assign different permission levels (viewer, editor, admin) to control what each team member can do
- Real-time updates: All team members see new emails appear instantly via WebSocket connections
- Collaborative debugging: Multiple developers can inspect the same emails, attachments, and headers together
This makes Mockmail perfect for dev teams, QA engineers, product managers, and anyone who needs to collaborate on email testing. You can have separate inboxes for different projects, environments (dev, staging, etc.), or teams, each with its own set of collaborators.
Shared inboxes are particularly useful for code reviews, QA workflows, and when demonstrating email functionality to stakeholders without giving them access to your entire Mockmail account.
Yes! Mockmail is built for team collaboration. You can easily share inboxes with your colleagues and control their access levels.
Team collaboration features include:
- Shared inboxes: Create dedicated inboxes that multiple team members can access simultaneously
- Team invitations: Invite colleagues to specific inboxes via email
- Role-based access control: Assign different permission levels (viewer, editor, admin) to control what each team member can do
- Real-time updates: All team members see new emails appear instantly via WebSocket connections
- Collaborative debugging: Multiple developers can inspect the same emails, attachments, and headers together
This makes Mockmail perfect for dev teams, QA engineers, product managers, and anyone who needs to collaborate on email testing. You can have separate inboxes for different projects, environments (dev, staging, etc.), or teams, each with its own set of collaborators.
Shared inboxes are particularly useful for code reviews, QA workflows, and when demonstrating email functionality to stakeholders without giving them access to your entire Mockmail account.