Job Opportunities API

Tessl is a fast-growing Series A startup based in London, founded by Guy Podjarny. We’ve raised over $100M from world-class investors including Index Ventures, Accel, GV, and Boldstart, and in 2025 we were ranked #2 in Sifted EU’s B2B SaaS Rising 100 and #20 in Sifted's AI 100. At Tessl, we are building the context layer for AI coding agents, and a platform for AI-native software development. As an early member of the team, you’ll help shape how we build, scale and support a company operating at the edge of AI and software development. OVERVIEW OF ROLE Join our engineering team to build real-time AI Native workflows, tooling, and interfaces that will reshape how developers create and maintain software. As a Software Engineer, you’ll be versatile and independent, excited to work with cutting-edge AI tools to build great products. We move quickly, but with purpose - balancing speed with collaboration and thoughtful execution. You’ll collaborate closely with product, design, and the wider Engineering team to bring AI Native development to life in a fast-paced, high-trust environment. WHAT YOU’LL DO No two days will be the same at Tessl! You’ll have a high level of autonomy and be able to make decisions based on what you believe will help you deliver the most success. Here’s an insight into just a few of the things you would be doing: - Design and implement new functionality that you discussed and reviewed with the product team - Spin up a proof of concept to showcase an innovative idea you’ve been thinking about - Rapidly prototype a new language integration for our code generation pipeline, then develop a plan for a scalable implementation. - Pair with a designer to fine-tune interactions in the UI, CLI or existing AI coding agents, making the user experience more intuitive and slick - Integrate a third-party service, e.g. for notifications, so we can focus our own cycles on Tessl’s core capabilities - Collaborate with other teams to plan an architecture that supports collaboration across the platform - Establish an end-to-end testing strategy to increase our confidence when deploying new features to production - Share your technical vision for a new product capability you’ll be leading with the wider engineering team for feedback and alignment WHAT WE’RE LOOKING FOR ESSENTIAL - Proven experience (typically 5+ years or equivalent) as a Software Engineer. You care about code modularity, structure and aesthetics and have firsthand experience in how software is built across teams and environments - Equally comfortable contributing to a mature codebase with strict CI criteria or hacking up a quick prototype to prove/disprove an assumption - Proven experience leveraging the best AI coding tools and agents to accelerate and enhance your own work and efficiency - Comfortable with fast-paced, high-autonomy environments: you’ve ideally thrived in an early-stage startup before - You have demonstrated usage of AI tools in your day-to-day work, and be excited about experimenting, learning, and harnessing the potential of new AI tools and approaches to transform software engineering NICE TO HAVE - Background in AI products or developer tools - Experience in rapid prototyping environments - Programming polyglot experienced in several languages of different paradigms (e.g.: JavaScript/TypeScript, Python, C or C++, Haskell, etc.) - Experience collaborating with AI researchers and bridging between research-focused and engineering-focused teams - Experience building & scaling REST APIs, particularly those conforming to JSON:API - Comfortable working on infrastructure (e.g., setting up CI pipelines, navigating Kubernetes) - If you have a personal or open-source project you’d like to share, we’d love to see it (GitHub links welcome!) SALARY AND BENEFITS Office: Our brand new 10,000 sq. ft office is in the AI hub of Kings Cross, London. We have generous