Updates and Fixes In August and September 2023

Mailsac remains committed to continuous improvement. Every day we improve the product based on customer feedback and SaaS best practices.

Here’s a summary of the latest enhancements.

  • New homepage and header navigation enhancements.
  • SAML Configuration Fix: enabled customer-supported account deletion when SAML is configured.
  • Testing: refactored and extended test coverage to payment processing.
  • Database: A series of database upgrades have been applied. This will continue through October to ensure we are leveraging the latest fixes and performance improvements.
  • Next.js: we continue overhauling the entire site using Next.js, in anticipation of a major restyle in 2024.

There are no breaking changes to any public API in these releases.

For further inquiries, please contact [email protected]

Scheduled Maintenance Notification for Mailsac – October 7th 2024

We want to inform you about a scheduled maintenance window set for October 7th between 0600 and 0800 PST (1300 – 1500 UTC). During this period, our team will be conducting a database upgrade to enhance the performance and reliability of our services.

Please note that requests to the REST API and the Web application may fail during this maintenance window. We recommend avoiding making requests to our services during this time to prevent any inconveniences.

We appreciate your understanding and cooperation. Rest assured that we are working hard to minimize the downtime and to continue delivering quality service to all our valued users.

Thank you for choosing Mailsac!

Best, The Mailsac Team

Mailsac Enhances Free Tier: Introduces One Free Private Address for Improved Privacy and Advanced Email Testing Capabilities

We’re delighted to announce a significant enhancement to our free tier plan, specifically tailored to meet the needs of Quality Assurance (QA) teams and automated testers. Effective immediately, all free Mailsac users will have access to one free private address, enabling them to maintain confidentiality during email testing and ensure privacy for sensitive testing communications.

The addition of the free private address empowers QA teams and automated testers with an extra layer of control over their email testing activities. With the free private address, they can separate and safeguard their testing correspondence, ensuring the confidentiality of valuable testing data. By seamlessly managing both public and private email addresses within a single Mailsac account, QA teams and automated testers can streamline their workflow and simplify the management of their testing environments.

“At Mailsac, we understand the critical importance of data privacy and confidentiality in the testing process. We are excited to offer QA teams and automated testers the advantage of one free private address to enhance their email testing capabilities,” stated Michael Mayer, managing executive at Mailsac. “This enhancement is a testament to our commitment to empowering professionals in the QA field with robust email solutions that prioritize privacy and security.”

In addition to the free private address, Mailsac’s free tier plan includes a comprehensive range of features designed to cater to the unique needs of QA teams and automated testers. These features include rolling message storage space, customizable email addresses, and reliable email forwarding and routing capabilities. The ability to forward emails to various testing integrations environments, via Slack, webhooks, websockets, and other Mailsac addresses, facilitates seamless communication and collaboration within a company’s testing ecosystem. Furthermore, Mailsac provides a robust REST API, enabling QA teams and automated testers to check and manage email messages with ease during their testing cycles.

To benefit from enhanced privacy, advanced email testing capabilities, and a comprehensive range of features, QA teams and automated testers can sign up for Mailsac’s free tier plan at https://mailsac.com/pricing. The inclusion of the free private address and the expanded email testing options demonstrate Mailsac’s commitment to meeting the specific requirements of QA professionals, enabling them to conduct thorough and secure email testing.

About Mailsac: Mailsac is the leading provider of secure and flexible email testing services, catering to the needs of individuals, small businesses, and organizations worldwide. With a strong emphasis on user privacy and data protection, Mailsac empowers QA teams and automated testers to conduct rigorous and secure email testing while maintaining control over their digital identities. From the free tier plan to enterprise offerings, Mailsac delivers unmatched email solutions and exceptional customer support.

For media inquiries, please contact: Michael Mayer Email: [email protected]

Why Professional QAs and Software Devs May Choose Mailsac Over Disposable Email

Email deliverability testing, and QA testing web apps with multiple account permissions, are critical aspects of software development and Quality Assurance (QA). Although disposable email websites and gmail addresses are a common choice for this task, they present several significant drawbacks for enterprises. This article will detail the advantages of using dedicated email deliverability platforms like Mailsac instead.

Limitations of Disposable Email

1. Security and Privacy

Disposable email platforms typically make all emails public. These websites are frequently crawled by scammers to acquire sensitive information.

Disposable email services often lack robust security measures, exposing sensitive test data. This lack of security can compromise the integrity of testing and risk breaches of confidential information. They rely on security through obscurity – random email addresses that are hopefully unguessable.

Disposable email providers typically do not have Information Security and Assurance programs, and cannot pass a Vendor Risk Assessment.

2. Business Agreements

The terms of service for disposable email services are often unsuitable for professional development and testing contexts. They can include problematic clauses and offer limited protections for users, which isn’t ideal for businesses. The terms and privacy policies tend to be non-negotiable.

3. B2B Interfaces

Disposable email services often lack capabilities for Business-to-Business (B2B) interfacing. This limitation can hinder the integration of these services into larger, automated testing suites, significantly limiting their usefulness in professional testing scenarios.

4. Uptime and Performance

Disposable email services are often slow and lack reliable uptime. These performance issues can introduce unnecessary delays into the testing process and create uncertainties around the reliability of test results. If an email was delayed, it can be hard to know if it was on your end, or theirs.

Advantages of Using Mailsac

Mailsac, as a dedicated email deliverability platform, provides a solution to these limitations and offers considerable advantages for professional QAs and software devs.

1. Enhanced Security

Mailsac prioritizes security, providing secure paid private inboxes and whole subdomains for testing.

You can test your application’s email functionality without risking sensitive data being leaked or public, or sold to a data broker.

2. Professional Business Agreements

Mailsac offers business-friendly terms of service, custom terms, P.O.s, multiple users, SSO and other features designed with the needs of professional QAs and software developers in larger companies with legal and security requirements. This provides a more suitable environment for business operations and testing.

3. Integration and functional testing

Mailsac provides powerful REST APIs, webhooks, and web sockets for integrating into CI/CD and workflows. Companies frequently integrate mailsac seamlessly into their automated testing suite. Using a consumer disposable provider often results in unexpectedly failed builds. Using a professional provider gives you comprehensive and efficient testing and enables continuous deployment.

4. Reliable Performance

Mailsac has high uptime and quick API and UI performance, ensuring a smooth and reliable email testing process. We believe performance is a feature.

5. Share test environment account email addresses

When you are testing a web application, you can use email addresses that are private to your Mailsac account to sign up for your app. Then share those inboxes with your teammates. For example, you may be testing a web app with two RBAC roles – administrator and readonly user. Each can have a unique mailsac email address. Your web app sends a sign-in link via email. All team members can access it (using mailsac’s multi-user or SSO feature). And since it’s not disposable email, the sign-in link to your app’s dev environment won’t be public.

While disposable email services may appear convenient, they come with considerable drawbacks for professional QAs and software devs. They can be against company policies because they may leak proprietary business information. Mailsac, with its robust features and focus on business needs, provides a far more effective solution for email deliverability testing.

QA Testing Email Deliverability using Mailsac: An Overview for QA Managers

The importance of Quality Assurance (QA) testing in software development and operations cannot be overstated. It ensures the product or system performs as expected, minimizing the risk of unexpected failures in production environments. A crucial aspect of QA testing involves testing email deliverability. This article will focus on how to use Mailsac, a leading tool in email testing, to execute this task effectively.

What is Mailsac?

Mailsac is a service providing temporary, “for-test-only” email addresses that can be used for testing and development purposes. Mailsac’s uniqueness lies in its capability to accept emails sent to any unique, auto-generated email addresses under its domain, thus eliminating the need for pre-generating email addresses or setting up a dedicated testing email server.

Why Use Mailsac for Email Deliverability Testing?

Email deliverability testing is vital to ensure emails are correctly dispatched from your application and are appropriately received by your users. Mailsac offers the flexibility to test various email formats and content, inspect the received emails, and verify they are correctly formatted and contain the correct data. This helps mitigate common issues such as emails being marked as spam, lost emails, or broken email formats.

How to Perform QA Testing with Mailsac

Let’s delve into the steps to conduct QA testing for email deliverability using Mailsac.

Step 1: Set Up a Mailsac Account

First and foremost, you need to create a Mailsac account. Visit the Mailsac website and follow the sign-up instructions.

Step 2: Send Emails to Mailsac

Next, send emails from your application to any addresses on the mailsac.com domain. Mailsac is designed in such a way that you don’t need to pre-generate the email addresses. Just decide on the address you want to use and send the email. The inbox will be created automatically when an email is received.

You can send the emails from anywhere, too – personal or work addresses, fake senders, CLI tools, software applications – without a separate sending gateway.

Step 3: Check Email Deliverability

After sending the emails, you can verify their delivery in the Mailsac interface. Here, you can view the received emails, check their contents, and confirm they are correctly formatted. Mailsac also enables you to check if attachments are included correctly using the Unified Inbox or API, and whether the links and images in the email are functioning properly.

Advanced Testing with Mailsac API

For more sophisticated or comprehensive testing, Mailsac offers a robust JSON REST API and Web Socket API. This empowers you to automate the process of sending emails, checking their delivery, and verifying their contents. These API calls can be integrated into your automated testing suite, enabling you to conduct in-depth email deliverability tests as a part of your regular testing process.

Wrapping Up

Mailsac presents a powerful and versatile method to test email deliverability as a part of your QA process. It allows you to send emails to any address on its domain, and the inboxes are created automatically when an email is received. By integrating Mailsac into your QA testing, you can significantly enhance the quality and reliability of your email notifications, thus offering a better user experience. Sign up and start receiving email in seconds.

Unveiling Mailsac’s New API Endpoint Feature: Inbox Filter

A look at filtering email messages with the Mailsac API

Mailsac has rolled out a new API endpoint feature, dubbed “inbox filter.”

It limits email messages using the to, from, and subject fields. Say goodbye to the conventional OR logic of /api/inbox-search and embrace the power of logical AND.

The Inbox Filter Endpoint: Technical Breakdown

The /api/inbox-filter API endpoint accepts the following optional query parameters:

  1. andSubjectIncludes: Filter messages by text included in the subject line
  2. andFrom: Filter messages by text included in the FROM envelope
  3. andTo: Filter messages by text included in the TO envelope

This endpoint delivers results only when at least one query condition is specified, otherwise, expect a 400 error. The response is capped at 100 results, so adjust your query or prune your account accordingly.

JavaScript Unit Test with Mocha and Axios

To illustrate the usage of the /inbox-filter API endpoint, here’s a JavaScript unit test using Mocha and Axios:

const axios = require('axios');
const assert = require('assert');

describe('Inbox Filter API Endpoint Test', () => {
  it('should return filtered messages', async () => {
    const mailsacApiKey = 'your-api-key-here';
    const endpoint = 'https://mailsac.com/api/inbox-filter';
    const andSubjectIncludes = 'Important';
    const andFrom = '[email protected]';
    const andTo = '[email protected]';

    const response = await axios.get(endpoint, {
      headers: { 'Mailsac-Key': mailsacApiKey },
      params: { andSubjectIncludes, andFrom, andTo },

    assert.strictEqual(response.status, 200);
    assert.strictEqual(Array.isArray(response.data.messages), true);
    response.data.messages.forEach((message) => {
      assert.strictEqual(message.subject.includes(andSubjectIncludes), true);
      assert.strictEqual(message.from[0].address.includes(andFrom), true);
      assert.strictEqual(message.to[0].address.includes(andTo), true);

Looking for a robust email testing solution that can simplify your workflow and improve efficiency? Look no further, friends. Mailsac offers powerful features like this new inbox filter API endpoint and many more, tailored to meet the needs of developers, testers, and businesses alike. Discover the benefits of Mailsac today and elevate your email management game. Try Mailsac for free or learn more about our plans and join our growing community of satisfied users at forum.mailsac.com.

Streamlined Mailsac Updates: Enhancing Email Testing with UI, Performance, and Security Improvements

Get ready for some boring news. At Mailsac, we release a steady stream of updates – week by week, all year long – with no fanfare. We avoid breaking changes wherever possible. Most of our customers have Mailsac integrated deeply into their CI/CD and QA processes. Breaking your build is not cool.

Here’s a recap of improvements we made over the past few months:

  • Updated UI interfaces for managing things like API keys, email addresses, and more. We’re modernizing the main website for security and ease-of-use. Stay tuned for a lot more of this.
  • Additional “Copy text” buttons and cross-browser compatibility improvements.
  • POP3 server fixes to some edge cases around Windows line endings.
  • Over 50 security updates to dependencies which are (hopefully) completely transparent to you.
  • Performance and security upgrades to our underlying servers.

Over time, SaaS services add too many features, getting clunky and slow user interfaces. At Mailsac we’re not beholden to venture capital or shareholders. Customers have our full attention. You pay us for dev and QA tools to help test email. Thus we prioritize speed and singleness of purpose to deliver you those tools. We want to be extremely helpful, yet stay out of your way.

If you’ve ever got issue with Mailsac, paying customers can contact us at [email protected]. A human being will reply pretty quickly, getting you unblocked. (For non-paying users, please ask for help at https://forum.mailsac.com )

The Hidden Costs of Neglecting Email Testing for Your Business

As a business manager in a software company, you understand the importance of effective communication with your customers. Email remains a critical channel for connecting with your audience, but many organizations overlook the importance of thoroughly testing their email sending capabilities. Failing to test your outbound email systems can lead to embarrassing mistakes, decreased customer satisfaction, and even regulatory consequences in certain industries. In this blog post, we’ll explore the downsides of neglecting email testing and explain why it should be a priority for your business.

Sending Duplicate or Incorrect Emails

One of the most common issues businesses face when not testing their email sending capabilities is accidentally sending duplicate or incorrect emails. This can happen due to software bugs, incorrect configuration, or simple human error. When customers receive multiple copies of the same email or emails containing inaccurate information, it can create confusion, erode trust, and damage your brand reputation. By investing in proper email testing, you can catch these errors before they reach your customers.

Personalization Mistakes

Email personalization is essential for connecting with customers on a deeper level. However, without proper testing, you may encounter issues like incorrect name insertion or the use of outdated customer data. These mistakes can make your emails appear unprofessional and impersonal, undermining your efforts to build strong relationships with your customers. Email testing can help ensure your personalization efforts are successful and your customers feel valued.

Missing Critical Notifications

When your email sending capabilities are not tested thoroughly, there’s a risk of failing to send important notifications to customers. This can include transaction confirmations, account updates, or even password reset emails. Delayed or missing notifications can lead to customer frustration, increased support requests, and potential security issues. Implementing a comprehensive email testing strategy can help ensure your customers receive timely and accurate notifications.

Deliverability Issues

Email deliverability is crucial for ensuring your messages reach your customers’ inboxes. If you don’t test your email sending capabilities, you may encounter issues like high bounce rates, being marked as spam, or being blocked by email service providers. These problems can severely impact your email marketing campaigns and customer communication efforts. Proper email testing can help you identify deliverability issues and address them before they harm your business.

Regulatory Consequences

In certain industries, companies are required to send timely and accurate notifications to customers, such as financial services or healthcare. Failing to meet these requirements due to untested email systems can result in regulatory consequences, including fines or legal actions. By prioritizing email testing, you can ensure compliance with industry-specific regulations and avoid potential penalties.


As a business manager, it’s essential to recognize the importance of thoroughly testing your email sending capabilities. Neglecting this critical aspect of your communication strategy can lead to various issues, including duplicate emails, personalization mistakes, missed notifications, deliverability problems, and regulatory consequences. By investing in proper email testing, you can ensure your messages are accurate, professional, and effective in reaching your customers. This will ultimately contribute to increased customer satisfaction and a stronger brand reputation.

A Guide to Customer Notification Laws: The Importance of Email Compliance

Email has become a crucial communication channel for companies to interact with their customers. While this powerful tool offers numerous benefits, it also comes with certain responsibilities. Various laws and regulations govern how businesses must notify their customers about important information. In this blog post, we will explore some of the most common customer notification laws and discuss the role of email in ensuring compliance.

This article is informational. It cannot substitute for advice from a lawyer.


The Controlling the Assault of Non-Solicited Pornography and Marketing (CAN-SPAM) Act is a US federal law that regulates commercial emails. While its primary focus is on marketing and promotional messages, the Act also has implications for transactional and relationship emails. Key requirements include: a. Providing a clear and conspicuous opt-out mechanism for recipients. b. Including the sender’s physical postal address in the email. c. Accurately representing the sender’s identity and email subject line.

By adhering to the CAN-SPAM Act, businesses can avoid potential fines and ensure their emails remain compliant with the law.

General Data Protection Regulation (GDPR)

The GDPR is a European Union regulation that governs data privacy and protection for EU citizens. It requires companies to obtain explicit consent from users before sending marketing emails. Additionally, the GDPR mandates that businesses must notify customers within 72 hours of becoming aware of a data breach. Failure to comply with GDPR requirements can result in significant fines.

California Consumer Privacy Act (CCPA)

The CCPA is a California state law that grants residents specific rights regarding their personal information. Under the CCPA, businesses must inform customers about their data collection practices and allow them to opt-out of the sale of their personal information. Email is an effective method for providing these notifications and ensuring compliance with the CCPA.

Health Insurance Portability and Accountability Act (HIPAA)

HIPAA is a US federal law that governs the privacy and security of protected health information (PHI). Healthcare providers, health plans, and other covered entities are required to notify individuals via email or written communication in the event of a breach of their PHI. The notification must be sent within 60 days of discovering the breach, and failure to comply with HIPAA regulations can result in hefty fines.

Financial Industry Regulations

Various financial regulations, such as the Gramm-Leach-Bliley Act (GLBA) and the Fair Credit Reporting Act (FCRA), require companies to notify customers about specific events or changes to their accounts. Examples include changes to account terms, privacy policies, or suspicious account activity. Email serves as a fast and efficient means of delivering these required notifications.


As a business, understanding and complying with customer notification laws is essential to protect your customers’ privacy and your company’s reputation. By leveraging email as a communication channel, you can efficiently and effectively meet the requirements of various regulations. However, it is crucial to remain up-to-date with these laws and ensure that your email practices align with the latest requirements. By doing so, you can foster trust with your customers and avoid potential legal consequences.

Email Delivery Testing: Node.js, Cypress, and Mailsac

Email delivery testing is an essential part of ensuring your application sends emails correctly and efficiently. With Mailsac, you can take advantage of its powerful REST API to simplify your email testing process. In this blog post, we’ll show you how to use Cypress, a popular end-to-end testing framework, in combination with Mailsac for seamless email delivery testing. We’ll cover setting up the Cypress environment, running tests, and provide plenty of code samples to get you started.

Setting up the Cypress Environment

First, you’ll need to have Node.js installed on your computer. Once that’s done, follow these steps to set up Cypress:

1. Create a new directory for your project and navigate to it in the terminal. b. Run npm init to create a package.json file. c. Install Cypress by running npm install cypress. d. Add a script to your package.json file to run Cypress:

"scripts": {
  "cypress:open": "cypress open"

2. Configuring Cypress and Mailsac API

Next, create a cypress.json file in your project’s root directory. This file will store your Mailsac API key and other configuration options:

  "baseUrl": "https://mailsac.com",
  "env": {
    "mailsac_api_key": "your_mailsac_api_key"

Replace your_mailsac_api_key with your actual Mailsac API key.

3. Writing Your First Cypress Test

Now, let’s create a test file in the cypress/integration folder. Name it email_delivery_spec.js. In this file, we’ll write a test that sends an email to a random Mailsac address and then checks whether the email was received.

// cypress/integration/email_delivery_spec.js

describe("Email Delivery Test", () => {
  it("sends an email and verifies its receipt", async () => {
      const randomEmail = `test-${Math.random().toString(36).substring(2)}@mailsac.com`;
      const testSubject = `Cypress Email Delivery Test ${Math.random().toString(36).substring(2)}`;
      const testBody = "This is a test email sent using Cypress and Mailsac.";

      // Send an email using your application's email sending method
      // ...
      // TOOD: integrate your app here!

      // Function to poll Mailsac API for received messages. It will be called
      // recursively.
      const checkEmail = async () => {
        let response = await cy.request({
          method: "GET",
          url: `https://mailsac.com/api/addresses/${randomEmail}/messages`,
          headers: {
            // Get a mailsac api key at: mailsac.com/api-keys
            "Mailsac-Key": Cypress.env("mailsac_api_key")
        const messages = response.body;
        const message = messages.find(msg => msg.subject === testSubject);

        if (!message) {
          return cy.wait(1000).then(() => {

        expect(message.from[0].address).to.equal("[email protected]");

        // Check email content for testBody text
        const textResponse = await cy.request(`https://mailsac.com/api/text/${randomEmail}/${msg._id}`);

        // Clean up by deleting the received messages. This could also be done in an afterEach block.
        await Promise.all(messages.map((msg) =>
            method: "DELETE",
            url: `https://mailsac.com/api/addresses/${randomEmail}/messages/${msg._id}`,
            headers: {
              "Mailsac-Key": Cypress.env("mailsac_api_key")

      // Start polling for received messages
      await checkEmail();

Replace [email protected] with your application’s sender email address.

This will open the Cypress Test Runner, and you’ll see your email_delivery_spec.js test listed. Click on the test to run it.