Senior Software Engineer - London

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

Salary: £60,000 - 100,000 per year

Requirements

• 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.

Technologies

• AI
• API
• Architect
• Backend
• C#
• Flow
• Support
• Python
• React
• UX UI Design
• ASP.NET
• Network
• Web

More

We are DeepL, a global AI product and research company building secure, intelligent solutions for complex business problems. Our Language AI platform is trusted by over 200,000 business customers and millions of individuals across 228 global markets. We are building the Operating System for Global Communication with an in-house AI stack, from training next-generation LLMs on our own NVIDIA DGX SuperPODs to delivering real-time Language AI at scale. You will join our Language Products Track in London within our Engineering department, working in a hybrid setup with flexible hours. We offer a diverse, internationally distributed team of more than 90 nationalities, open communication and regular feedback, virtual shares, regular in-person team events, monthly full-day hacking sessions, 30 days of annual leave, access to mental health resources, and a competitive benefits package tailored by location.

last updated 37 week of 2026