We’ve gathered questions you are frequently asking and grouped them into four categories: general questions, settings and integration, billing questions and payment options, and technical problems.

In this article

General questions

What is Mailtrap?

Mailtrap is a fake SMTP server designed to test, view, and share emails sent from the development and staging environments without spamming real customers or flooding your own inboxes.

Mailtrap is not a transactional email delivery system, it collects all emails from the Local Host, Stage, QA, environments, and lets you test, preview, and debug your HTML emails.

Learn how exactly Mailtrap can help you streamline email testing processes from our case study with The Software House.

Can emails captured by Mailtrap only be viewed through its interface?

You should not necessarily stick to our web interface. Instead, you can forward every single email to your or a teammate's mailbox. You can even enable automatic forwarding, and Mailtrap will act as a proxy between your application and your email client. In this case, you can be sure you won't miss important messages from the QA environment, such as exception notifications.

Read the Email Forwarding article for more details. 

How does Mailtrap render emails?

Mailtrap renders emails in the same way browsers do, which means no additional stylesheet or CSS presets are applied by default.

Which browsers does Mailtrap support?

Mailtrap supports the latest two versions of the Chromium-based browsers, Firefox, and Safari, unless otherwise noted

Major desktop browsers:

Major mobile browsers:

Please note that Internet Explorer is not supported anymore, as Microsoft is gradually deprecating its support and recommends Edge as a more modern and secure alternative.

Can Mailtrap show what email will look like in various email clients?

Mailtrap is compatible with web email clients.

Mailtrap does not show exactly how an email will look like in any email client. It renders HTML as-is, without external CSS styles. Also, Mailtrap provides HTML checks and demonstrates potential errors that different email clients may experience when rendering an HTML email.

You can also forward emails to Outlook, Thunderbird, etc., and use these desktop clients to view them.

What does Mailtrap do with <style> tag?

Mailtrap doesn't rip the style tag out of the email templates.

What does Mailtrap do with <script> tag?

For enhanced security, Mailtrap removes all <script> tags from HTML.

Can I use Mailtrap as a /dev/null SMTP server?

The main goal of Mailtrap is to help you test emails, and /dev/null is not part of it. Should you need /dev/null SMTP server, please use the following built-in Python SMTP server: $ python -m smtpd -nc DebuggingServer localhost:2525 > /dev/null

What is the email size limit?

The maximum size of an email including attachments ranges from 5 MB to 25 MB. It depends on your subscription plan. If your message exceeds this limit, you will get the following error: '552 5.3.4 Error: message too big'

What is the SMTP rate limit for the inbox?

It is the number of emails you can send to each of your inboxes every 10 seconds. The SMTP rate limit depends on the subscription plan. For more details, check out the Pricing page.

What is the monthly messages limit?

It is the maximum number of emails you can test with Mailtrap and get in all your inboxes per month. The total emails per month limit depends on the subscription plan. For more details, check out the Pricing page.

If you reach your monthly limit, you'll receive the SMTP protocol error: "535 5.7.0 Monthly messages limit reached". We also send out notifications for having used 80%, 90%, and 100% of the monthly limit.

To continue testing when you're over the sending limit, please upgrade your subscription plan. Alternatively, you can wait until the next billing period starts, when the limit is reset.

Does Mailtrap comply with GDPR?

The General Data Protection Regulation (GDPR) came into effect on May 25, 2018. We have implemented appropriate technical and security processes to ensure Mailtrap's full compliance with this regulation. For more details, refer to our Privacy Policy, Navigational Information, and Data Protection Agreement.

Do you have a bug bounty program?

We do not. In case you have found a vulnerability on our website that you are eager to report to us, you are welcome to do so at support@mailtrap.io. All issue reporters will be mentioned on our changelog page.

Should I pay to use Mailtrap?

Mailtrap provides a free subscription plan for new users who want to evaluate Mailtrap, or intend to use it on a personal side project. For larger teams, we offer sets of features within several paid subscription plans. To choose one that best fits your needs, check out the Pricing page.

Can I send emails to real end-users using Mailtrap?

Yes. As a part of our Beta program, you can get early access to Mailtrap Transactional Sending. Please contact support@mailtrap.io to try it out. Read more.

How do I integrate Mailtrap with my application?

The integration is very simple and takes just a couple of minutes:

  1. Sign up by creating a free account.
  2. Go to My inbox in the My Inboxes project.
  3. Copy a code sample for your framework from the Integrations section or copy credentials provided in the SMTP Settings section. 
  4. Embed them into your app code in development, QA, or staging environment.

Alternatively, you can send messages from your email client or another application to your Mailtrap inbox using its email address. You will find it in the Email Address tab in your inbox. It works in the same way as any other email address - just don't forget to enable it by clicking the Enable icon in the three-dots menu.

For more detailed instructions, check articles in the " Sending emails to Mailtrap" category. 

Can I force an encrypted connection?

Yes, you can enforce encrypted connections. Mailtrap SMTP server uses STARTTLS which works for all SMTP ports. We support only TLS connection because of the POODLE vulnerability (SSLv2 and SSLv3 are disabled).

I would like to whitelist smtp.mailtrap.io on my firewall. What is Mailtrap's IP range?

We use AWS with auto-balancing, so our IP ranges are the following: https://ip-ranges.amazonaws.com/ip-ranges.json

I have a problem integrating Mailtrap with my app, what should I do?

Please send us an email at support@mailtrap.io describing the issue; we'll try to help you ASAP.

Billing questions

Subscription plans and account ownership

Your subscription plan limits apply only to the inboxes and projects you own. Shared inboxes and projects refer to their owners. If you see an inactive inbox, check whether it is shared. If so, its owner should activate it.

This way, the project's or inbox's team members can use Mailtrap according to the owner's subscription plan limitations, without the need to change their own subscription plan.

How can I activate my inboxes?

Here is a list of all the inboxes you own. If you downgrade to a subscription plan with a lower inbox limit, you will be asked to activate those inboxes you wish to continue using. Afterwards, activation is available at the Billing dashboard.

Please note that you can activate an inbox only once. In case you activated an inbox by mistake, please email us at support@mailtrap.io or upgrade to a higher plan that includes more inboxes.

When will I be charged for the change to the subscription plan?

If you upgrade to a higher plan, we create a prorated transaction based on the price change for the rest of the billing cycle. If you downgrade, the new price will be applied to the next billing period. If the transaction for the prorated amount fails, the subscription update is canceled.

Do you offer a yearly subscription?

We currently only offer monthly subscription plans.

Can I pay for Mailtrap by invoice using bank transfer?

Unfortunately, it is not possible. The only payment method that is currently available is bank card payments.

Can I receive a purchase order?

We don't provide purchase orders for Mailtrap subscriptions.

How can I get an invoice?

We send invoices by email once your credit card is successfully charged. Fill in the requested details in the Setting tabs of the Billing section in your Mailtrap account, and indicate your financial email address for invoices and billing notifications.

If the financial email address is not set up, you will receive invoices and billing notifications to your main account email address.

Can I move my billing subscription to another account?

For security reasons, we can't migrate payment credentials and subscription billing plans between accounts. Otherwise, you can change your account email address in the User Settings of your Profile page or send us a request at support@mailtrap.io.

Do you offer discounts to nonprofit open-source organizations?

Yes, we provide a Team plan for free for nonprofit open-source organizations. Please send us a document that verifies that you are a representative of a nonprofit open-source organization to support@mailtrap.io (a W-9 form or any other legal document), and we'll be happy to assist you.

I have a technical problem

Visit the troubleshooting section for the answers to the most common problems or contact our support

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