DeepL API client libraries and developer experience: A year in review

Developer experience is still relatively new to the corporate lexicon, and interest in the user experience of software developers has been growing steadily over the past decade-plus.  It's easy to see why! Modern software projects can be painfully complex, and mitigating this complexity means investing in tooling and resources for developers beyond the core product—from documentation, tutorials, and code samples, to community and new support channels. 

As a company that provides an API to tens of thousands of users globally, developer experience is always top of mind. Thus, we’d like to share a quick update of our work in the past year and what we have planned for the future. 

API client libraries

Client libraries are core to our developer experience efforts, allowing users to work in an ecosystem they’re familiar with and write simpler, more efficient code. 

Client libraries were the first set of open-source projects to come out of DeepL. Open source makes it easier for users to customize the libraries and to share feedback with us directly.

We released our first client library in Python in August 2021 and since then, we’ve released libraries in .NET, Node.js, PHP, and Java. One year later, in August 2022, about 7% of all DeepL API requests (representing billions of characters translated) were made with one of our client libraries—and thousands of API users made at least one request with a client library.  

In the coming year, we plan to add at least one more client library in Go, and we’ll continue to update our existing client libraries as the API adds new capabilities.  

Have ideas or feedback related to our client libraries? Create a GitHub issue in the right repository to get the conversation started. We monitor Stack Overflow for the #deepl tag too!

OpenAPI specification

In June 2022, we published an OpenAPI specification for the DeepL API. This makes it easier for users to generate clients for programming languages not yet supported by DeepL and to explore the API with Swagger UI or Postman. The spec will also make it easier for the DeepL team to maintain documentation in a consistent and efficient way. We recently rewrote our documentation based on the OpenAPI specification, making it easier for us to improve the documentation moving forward.   One such improvement we’ve planned is to add client library code examples throughout the documentation alongside the existing cURL and HTTP examples. 

You can find the OpenAPI spec in GitHub here.

API sample projects

In the past year, we’ve heard feedback from users who’d like to see more examples to use as a starting point for their own project, or to reference when integrating the DeepL API. In August 2022, we published our first ever sample project for the DeepL API—a sample script for Google Sheets that makes it possible to translate cells with DeepL. Like our other GitHub projects, this sample project is open-source under the MIT License. 

Although we’re still defining our “sample project roadmap,” we hope this is the first of many sample projects that we’ll share in GitHub. As always, feedback is welcome through opening a ticket!  

We look forward to hearing your feedback on our ongoing developer experience work. We’ll also continue investing in new API features and support for new languages and glossary pairs in DeepL. 

New to the DeepL API and ready to get started? Sign up to translate up to 500,000 characters per month for free.


3 Key Takeaways:

  1. We released our first API client library in Python one year ago in August 2021 and since then, the library has been utilized by thousands of Free and Pro API users. 

  2. Along with Python, we released client libraries in .NET, Node.js, PHP, and Java—as well as an OpenAPI specification. 

  3. We'll continue to invest in developer experience through more client library work, documentation improvements, and code samples.