Over the last four years, Squarespace’s product offerings have expanded significantly. To keep up with Squarespace's growing platform, we needed to scale our functional test coverage. We created Firepit, a user interface (UI) for configuring and triggering tests. Firepit empowers engineers to easily run custom test suites in Squarespace's deployment environments. The foundation of our testing philosophy is straightforward: write tests that are simple, readable, and stable.


With continuous deployment enabled for critical backend services and Squarespace’s entire application frontend, it is essential to have meaningful, reliable UI tests. Anything merged to master will ship to production automatically with no human checks, so these tests are the last guarantee that basic features of our product work. To effectively test Squarespace’s complex, interaction-heavy application, we built a uniquely powerful browser testing tool called Charcoal.

Designing web service APIs can be a tricky art form. APIs serve as a virtual playbook necessary for interacting with your business domain, and more importantly, they are the contracts that bind service owners with their consumers. Therefore, getting design right early on is an important part of the service engineering we do at Squarespace.

It is important to understand how containers are implemented using Linux control groups (cgroups) and namespaces. Understanding the features and limitations has helped us dramatically improve the performance of our Java services especially under stressful scenarios.

Squarespace hosts millions of websites on our cloud-based website-building platform. The reliability of these sites is a top priority for us. We’re consistently implementing the best technologies and safeguards to enable quick load times and prevent outages. The measures we take allow our customers to create Squarespace websites with confidence.

Over the last three years, we have begun to make investments in architectural changes, including the breakup of our monolith into smaller, well-defined service boundaries. In this blog post, I will touch on a challenge that the Core Services Team faced: defining the pillars and core functionality of a service.

How do we become familiar with such a wide range of customers to build them the products they need? Many Squarespace sites are heavily visual and contain a lot of images and photos. If we were to only search with text, we’d miss crucial visual and stylistic features of many Squarespace sites.

As part of our ongoing efforts to improve user experience on the Squarespace platform, we added a feature to display thumbnail previews of all of your account’s sites in the account picker. Since we didn’t have any existing functionality around screenshot generation, this was something we had to build from scratch. In this post we’ll talk about the screenshots microservice solution we came up with.