Senior Full-Stack Engineer — React, Python/C#, Hybrid

DeepL; Greater London; Hybrid; GBP 60,000 - 100,000; Full time

Job summary

DeepL in London (hybrid) is seeking a strong front-end heavy full-stack engineer to architect and build features for our translation products. You will craft interactive UIs in React and design backend logic in Python and C#/.NET Core, balancing speed with accuracy for complex document formats.

Join a global AI team in a hybrid London setup, collaborating with Research, Product and Design to deliver seamless enterprise localization workflows and transparent performance metrics.

Qualifications

• We look for a product-first mindset and care deeply about who uses our software.
• We want a strong front-end heavy full-stack engineer who is comfortable traversing the stack to deliver features.
• We look for experience building highly interactive, performant UIs in React.
• We want experience designing supporting backend logic in Python and C#/.NET Core, with support of agentic tooling.
• We value high agency and a bias for action.
• We look for someone who is comfortable unblocking themselves and the team.
• We want a system thinker for UI/UX who understands how simple interfaces can hide complex backend systems.
• We look for someone who can design systems that handle large document states, manage complex terminology rules, and maintain high browser performance.

Responsibilities

• Architect and build complex, user-facing features across our primary translation products.
• Build UI for the translation flow.
• Engineer backend logic to parse and translate complex document formats such as PDF, Word, and PowerPoint without losing formatting.
• Integrate our products directly into enterprise workflows.
• Solve the challenge of building an interface that feels instant and simple for consumer users while supporting complex enterprise collaboration and localization workflows.
• Make high-stakes technical decisions regarding state management, API integrations, and performance.
• Prototype, measure user friction, and iterate quickly when requirements are ambiguous.
• Collaborate closely with Research, Product, and Design to translate complex AI constraints into an intuitive UX.
• Build transparency and performance metrics directly into the product.

Skills

React

Frontend

Python

C#/.NET

UI/UX design

Performance

System thinking

API integration

State management

Tools

ASP.NET

React

Job description

DeepL in London (hybrid) is seeking a strong front-end heavy full-stack engineer to architect and build features for our translation products. You will craft interactive UIs in React and design backend logic in Python and C#/.NET Core, balancing speed with accuracy for complex document formats.

Join a global AI team in a hybrid London setup, collaborating with Research, Product and Design to deliver seamless enterprise localization workflows and transparent performance metrics.