Berlin, Germany

Joshua Christl

Software Engineer based in Berlin

I build websites and complex products, end-to-end.

Backend, frontend, infrastructure, cloud - whatever it takes to ship. AI-first: building AI-powered products, and using AI to build faster.

Experience

Software Engineer · DeepL

2025 - present · Berlin

All things document translation, vision models, AI Engineering and building agentic workflows. Member of DeepL AI Labs.

Work featured on the DeepL tech blog

QA Engineer · DeepL

2023 - 2025 · Munich

Backend test automation. Owned the end-to-end test suite for document translation.

Featured on the DeepL blog

Founder / Engineer · Freelance

2023 · Munich · remote

Built two SaaS web apps from scratch, solo - Python, FastAPI, React, AWS, Docker.

Software Engineer (working student) · CQSE GmbH

2020 - 2023 · Munich

Core dev on Teamscale: static analysis, test-gap & test-impact analysis, clone detection, IDE plug-ins. Java, TypeScript, React.

Software Engineer (internships) · Klinikum rechts der Isar

2020 & 2022 · Munich

Tools for dermatologists: image segmentation and classification. Python, Flask, TypeScript, Svelte.

Education

M.Sc. Computer Science · TUM

2021 - 2023

Engineering software-intensive systems, formal methods. Thesis: empirical study of manual classification & traceability of test gaps.

B.Sc. Computer Science · TUM

2017 - 2021

Thesis with Klinikum rechts der Isar: deep-learning outlier detection in dermatological images.

Publication

Outlier detection in dermatology: Performance of different convolutional neural networks for binary classification of inflammatory skin diseases

Journal of the European Academy of Dermatology and Venereology (JEADV) 2023, 37(5), 1071-1079

Benchmarking convolutional neural networks on binary classification of inflammatory skin diseases - a step toward reliable outlier detection in dermatological imaging. Grew out of my bachelor’s thesis with Klinikum rechts der Isar.

doi:10.1111/jdv.18853

Blog mentions

How DeepL built better document translation

DeepL Blog · 2025

The story of raising the bar for document translation: turning customer feedback into metrics, metrics into benchmarks, and benchmarks into visibly better documents.

Stack

I use whatever technology it takes to build. I love Java, Python, React and TypeScript but have also extensively programmed in C# and Go. I also like functional programming languages such as OCaml. Infra-wise, I work with AWS, Azure, Hetzner Cloud.