Babbel Bytes

Insights from the Babbel engineering team

From documentation to empowerment

Christian Requena

This is the second in a series of blog posts entitled “How We Work” in which we share with you how we work in Engineering @ Babbel.

Without history, there is no future.

To effectively make technical decisions we need to share a common understanding on the context in which we work. Thus, we need to know “how did we get here?” and then “where do we want to go?”.


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AWS Lambda and APIGateway as an AJAX-compatible API-endpoint with custom routing

Nikita Simakov

AWS Lambda is a powerful tool to build serverless applications, especially when backed by APIGateway and Swagger. Lambda executes your code without the need for you to manage a dedicated server. APIGateway provides a front-end for your Lambda to be easily accessed from the Internet via endpoints that can be configured with the Swagger framework. In this article we’ll take a look at one specific example of an AJAX endpoint that uses custom path parameters, something typically problematic to implement because of Swagger limitations.


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The evolution of our staging environment

Kirill Zonov

Today, we will be talking about staging environment at Babbel and how we recently improved it. As a reader of our tech blog, there’s a good chance that you are already familiar with the concept of a staging environment. I will nevertheless start with a brief definition, so that we establish a common understanding before going into the details of how to secure a staging environment. Bear with me.


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How We Work

Nehal Shah

This is the first in a series of blog posts entitled “How We Work” in which we share with you how we work in Engineering @ Babbel.

When I started at Babbel earlier this year, I was struck by how many great ideas the engineering department here had and how they saw their technology evolving. In fact, in my first week, a compelling document was shared with me outlining the engineering strategy. When we attempted to put the strategy into action, we encountered many problems:

  • Prioritizing tasks related to the engineering strategy proved difficult because we had no way to judge their importance
  • Tasks were often started but not finished because there was a lack of time and urgency

When we retrospected on what was done – and not done – we realized something that should have been obvious to us: the strategy wasn’t really a strategy at all. A strategy enables you to make decisions. This was rather a list of tasks.

There was no overarching vision of the future guiding us. We had no sense of mission.


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Juggling multiple build stages and test environments with TravisCI

Jana Rekittke

At Babbel, we employ continuous integration to detect issues early in the development process. Our CI does not only automate the build and run different test suits but also handles some tasks for documentation purposes. With so many moving parts, the setup is not trivial. We (one of the Web teams) share our TravisCI setup here on Babbel Bytes in the hope that some of you find it helpful for your own applications.

Our application and its unit tests are written in JavaScript. Additionally, we have Selenium based UI tests written in Ruby. We use TravisCI to run all our tests and build the application for deployment. After a deployment, we also need to build a so-called Storybook and upload it to AWS S3. Storybook is a UI Development Environment. Finally, we check for vulnerabilities using a service called Snyk.


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Spelling correction with Levenshtein distance

Josephine Wright

How similar are the words ‘hear’ and ‘here’?

There are many answers to that question. First and foremost, ‘hear’ and ‘here’ are indistinguishable in sound. Meaning, a fluent English speaker will pronounce ‘here’ just as they pronounce ‘hear’. However, ‘here’ and ‘hear’ are different semantically or, rather, their definitions are distinct. ‘Here’ and ‘hear’ are also different in spelling.

Spelling is a particularly important issue for our users, here, at Babbel. It’s common for language learners to make spelling mistakes in a new language. It’s also common for users to make typo mistakes while using a mobile or web application. As we’re constantly looking for ways to improve our language learners’ experience, these issues were addressed in a recent project by using a popular algorithm called Levenshtein distance.


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Hackday memories

Alyssa Windmüller

A perfect blue sky. Warm sunshine. People wearing T-shirts and sunglasses. And yet, the orange and red leaves covering Berlin’s streets announce the cold season arriving soon. As we watch the leaves fall down, we start reflecting back on the warm summer day we all retreated out of the office to hack our hearts away working on brand new, exciting ideas at Hackday 2018. On June 7th, 110 Babbelonians (from Engineering, Product, Didactics, Marketing, and HR) took a break from their daily work and came up with a total of 18 projects entered into the final competition.


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