Join to apply for the Software Engineer role at Tessl

Tessl is a Series A startup based in London, focusing on AI Native Development. We are building the pioneering platform for AI Native Development and shaping the dev movement and ecosystem that drive it. As an early member of our team, you’ll have the opportunity to shape the future of how software is created and maintained.

Overview

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

• 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 catering and regular social events. Staff are expected to be in our London HQ at least 3 days a week on anchor days (Monday, Tuesday and Thursday).

Salary: We offer a competitive salary based on experience and skills, benchmarked against industry standards.

Benefits: 25 days holiday, health insurance (including dental and vision) for dependents and partners, a company-matched pension, commuting stipend for those outside London, and a cycle-to-work scheme.

Application Process

Here’s an outline of what you can expect during our interview process:

• Introductory Call with one of our engineering leaders
• Take-Home Exercise: a practical challenge based on real scenarios you might tackle at Tessl
• On-site Technical Session: pair with two of our lead engineers to build on your take-home exercise
• Culture Conversation with our People Lead
• Leadership Discussion with the Head of Engineering and potentially the CEO or Head of Product

Our final stage focuses on strategic alignment and long-term vision. You’ll learn more about Tessl’s roadmap and how you could contribute to our mission.

Throughout the process, if you have any specific requirements or need adjustments, please let us know: we’re happy to accommodate. We value a warm, inclusive environment and diversity in tech. If you like the sound of this role but aren’t sure, please apply anyway.

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Seniority level: Mid-Senior level

Employment type: Full-time

Job function: Engineering and Information Technology

Industries: Software Development