Key differences between Mailtrap and Postmark 

1. With Mailtrap free tier, you can send 1,000 emails/month (user-triggered, bulk, or marketing) and test 100 emails/month.
2. In addition to transactional and bulk streams, Mailtrap has Email Marketing. 
3. Mailtrap allows you to manually import suppression lists or upload a CSV file. You can also export suppressions in CSV.
4. Depending on the pricing plan, Mailtrap stores emails in the Email Logs for up to 30 days. Email content and historical data are stored and accessible between 3 and 7 days without additional fees. 
5. Mailtrap offers Email Testing. This is an email sandbox for inspecting HTML/CSS, spam scores, etc., and debugging emails in staging, dev, and QA environments before sending them to recipients. 
6. Mailtrap offers monthly recurring plans with an option to request annual billing/plan.

Similarities between Mailtrap and Postmark  

1. Support for sending with SMTP or REST API. 
2. Separate streams for transactional and bulk emails. 
3. You can use return-path records and DKIM to verify a domain. 
4. Both Postmark and Mailtrap allow you to add unsubscribe options to emails without coding.

Terminology comparison

General step-by-step migration flow

*Postmark allows you to export just 500 records as CSV from their Activity menu. If you need to export more, you’ll need to use messages API. 

Getting started

To start sending emails with Mailtrap, you only need to create an account and verify your domain. Domain setup and verification are done from the Sending Domains menu. Read this article to learn more about that process.

Domain verification

• Once your domain is verified using the provided DNS records, it undergoes an automatic Compliance Check. This process usually takes from a couple of minutes to several hours. You can send emails only after the Compliance Check is fully passed and you see the verified status next to your domain.

• Set unsubscribe options with Mailtrap and import your suppression lists from Postmark (as CSV). Also, remember to import your email list and HTML templates into Mailtrap. 
• Optionally, create webhooks to receive information about bounces, spam complaints, opens, clicks, and other events.
• Enable open and click tracking to understand how customers interact with your emails.

Sending with Mailtrap SMTP

SMTP endpoints

Mailtrap Server	Postmark Server
live.smtp.mailtrap.io bulk.smtp.mailtrap.io	smtp.postmarkapp.com smtp-broadcasts.postmarkapp.com

SMTP ports

Port	Function	Mailtrap	Postmark
587	Recommended for encrypted TLS SMTP connection.
25	May be problematic due to blocking by some mailbox providers to avoid abuse.
2525	For unencrypted/TLS

SMTP Configuration

Go to Sending Domains and click the verified domain you want to send emails from. Go to the Integration tab and click Integrate under Transactional or Bulk Stream, depending on the type of emails you’d like to send.

Copy and paste the credentials (for the stream you chose) into your app or project, and you’ll be ready to start sending emails. Read more about SMTP integration here.

Note: Turning TLS on is mandatory, as mentioned in the credentials.

Sending with Mailtrap API

Mailtrap API tokens

Mailtrap automatically creates a token when you add a domain. By default, the token has Domain Admin access permission. You can edit the token permissions in the API Tokens menu under Settings.

Learn more on how to manage API tokens in our guide.

API Mapping

API type	Mailtrap	Postmark Naming
The basics	General	Introduction
Email Sending	Send email	Email API
User management	Manage user or token permission
Email testing	Email Testing API	Servers API → servers → DeliveryType → Sandbox
Webhooks	Receive events	Webhooks API
Bulk Sending	Send email	Bulk Email

API Libraries

At the moment, nine libraries are available at Mailtrap.

Programming Language	Mailtrap	Postmark
Node.js	Node.js SDK	Postmark Node.js
NodeMailer (Node.js)	NodeMailer SDK	Not supported
PHP	PHP SDK	Postmark PHP
PHP (Laravel + Symphony)	PHP SDK	Not supported, community drivers/plugins only
Ruby	Ruby SDK	Postmark Ruby Gem
Ruby (ActionMailer)	ActionMailer SDK	Not supported
Python	Python SDK	Not supported, community libraries only
Elixir	Elixir SDK	Not supported, community libraries only
Java	Java SDK	Postmark Java

API Authentication

We use Bearer authentication. Pass the API token into the code under the header Authorization.

Permissions/User management

If you are on the Business plan or higher, you can add users to your account and manage their permissions. To do it, click the User Management menu under Settings, then the three dots (more menu) on the right. You can also manage users and permissions with API.

Based on the permissions users get, they can view, access, and/or modify specific functionalities of an app. Note that a user needs Admin permissions to get authenticated and send emails via API.

Additionally, Mailtrap allows you to enable or disable app-based 2FA for all or some users within your account with an option to enforce 2FA for all users. Check our 2FA guide for more details. 

If you want to learn more about managing users’ permissions, click this link ◀️.

ActionMailer Balancer for smooth migration

For Ruby on Rails applications, Mailtrap offers an ActionMailer Balancer that makes the migration smooth. 

ActionMailer extension allows for the proportional distribution of the email-sending load between two different sending services and mitigates sending risks.

After you install the Balancer and make some minor configurations, ActionMailer’s sending method will get extended.

For more detailed info on the boilerplate and use in development, read the Mailtrap ActionMailer Balancer GitHub page.