Hi, I'm Jonas - Your Freelance Software Engineer from Würzburg/Germany 👋

Specialized in building robust and scalable React.js applications.

Learn more

(currently available for new projects)

Potrait Freelance Software Engineer Jonas Herrmannsdörfer
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Proud to have collaborated with industry leaders and cutting-edge startups.

paceteq
fraunhofer iis
faaren

Key Facts about me

8+ years of experience
For the past 8 years, I have been helping create React.js applications for both small startups and large enterprises.
International Conference Speaker
I share my knowledge about React.js and frontend development at international conferences like DEV World in Amsterdam.
React.js trainer
I help experienced developers and entire teams switch from their current technology to React by teaching them basic to advanced JavaScript and React concepts.

Preferred Technologies

Depending on my clients' needs, I work with various React.js-related technologies. I prefer using Playwright for end-to-end testing, Next.js for full-stack applications, TailwindCSS for styling, and Testing Library for unit testing.

React Logo

React

Typescript Logo

Typescript

TailwindCSS Logo

TailwindCSS

Next.js Logo

Next.js

Playwright Logo

Playwright

Testing Library Logo

Testing Library

You want to know what my customers say about me?

Happy customers

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Jonas supported our association Arbeitskreis Psychiatrie-Patientenbetreuung e.V. in Bamberg very much in setting up our website. Together with us, he created the concept incl. target group analysis, developed a viable concept, design and navigation from this and carried out the implementation. Jonas directly took up our ideas and concepts, developed them further and implemented them in such a way that they fit into the overall concept of the website. He also contributed many of his own ideas, which opened up new perspectives for us and greatly enriched the website. He always responded to special requests and wishes individually and with great patience. We are extremely satisfied with the result, the website looks very professional and exceeds our expectations by far. The collaboration with Jonas was very effective and characterised by great mutual respect. Jonas managed to lead us to a workable compromise even in the case of contentious issues. He informed and educated us extensively about the complex aspects that need to be considered when building a website. In doing so, he conveyed technical information in such a way that we non-experts understood the issues. He always kept us up to date on the progress. We received answers to questions or requests for changes quickly and the concrete implementation also took place very promptly. Overall, the contact with Jonas was absolutely pleasant and uncomplicated due to his relaxed and friendly manner. With our rather limited financial capacities and hardly any of our own expertise, we are extremely grateful that Jonas provided his entire, very extensive commitment for us free of charge! Otherwise we would not have been able to design or pay for such a website. Many, many thanks for that!

Board member Arbeitskreis Psychiatrie e.V. Leonie Jost

Leonie Jost

Board member

Arbeitskreis Psychiatrie e.V.

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Jonas supported us in the subproject V2X (Vehicle-to-Everything) within the program “5G-Bavaria Testcenter“ as a freelance software developer. In doing so, he implemented the frontend application of the subproject using Next.js. We were particularly satisfied with the speedy implementation, good documentation and test coverage of the written code. To this day, we are thrilled with the stability of the developed application. In addition to the implementation of the frontend, he also advised us on the integration of CI/CD pipelines and pointed out optimization potentials in agile working with tools like Jira and GitLab. His open and pragmatic way made communication with the backend teams very easy and enabled fast integration of new features. He also mentored junior developers in an exemplary manner and enabled them to continuously develop themselves through knowledge transfer and mentoring, so that they could take over the project independently after his departure. We really appreciated working with Jonas and are happy to recommend him!

Senior Scientist Fraunhofer Institute for Integrated Circuits (IIS) Thomas Dettbarn

Thomas Dettbarn

Senior Scientist

Fraunhofer Institute for Integrated Circuits (IIS)

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Jonas has been supporting us as a freelance web developer since mid-2017. Since then, he has been helping us to facilitate the recruiting process for our customers through digital workflows. We are very satisfied with his work, his superb communication and the pragmatic way in which he always delivers excellent solutions. We are therefore very happy to recommend him!

Executive Board HR Recruitment & Interim AG Olaf Schaefer

Olaf Schaefer

Executive Board

HR Recruitment & Interim AG

Let's work together

I'd love to discuss how we can work together to bring your project to life. Let's talk about my approach, availability, and rates.

Contact Me to Get Started