Full-Stack Engineer

About Tessl

Tessl is a Series A startup based in London, founded by Guy Podjarny who also founded dev-first security company Snyk.

At Tessl, we believe AI will fundamentally change the way software is developed, beyond short-term wins like code generation and bug fixing. As a result, we’re reimagining the software creation process to be truly “AI native,” enabling a whole host of ground-breaking improvements that we believe will transform our industry.

As an early member of our team, you’ll have the opportunity to shape the future of how software is created and maintained.

Overview of role

Join our User Journeys team to build real-time AI-native workflows, tooling, and interfaces that will reshape how developers create and maintain software.

As a Full Stack Engineer, you’ll thrive on variety: from refining intuitive user interactions in our Tiptap-based editor to developing a CLI that empowers developers to interact seamlessly with Tessl.

You’ll report to Joe Holdcroft and collaborate closely with product, design, and the wider Engineering team to bring AI-native development to life in a fast-paced, high-autonomy 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 some of the things you could be doing:

• Spin up a proof of concept to showcase an innovative idea you’ve been thinking about

• Pair with a designer to fine-tune interactions in our UI, making the user experience more intuitive and slick

• Integrate a third-party service, e.g. for notifications, so we can stay focused on Tessl’s core capabilities

• Collaborate with other teams to plan an architecture that supports real-time streaming and collaboration across the platform

• Establish an end-to-end testing strategy to increase our confidence when deploying new features to production

• Author a decision document to articulate your technical vision for a new product capability you’ll be leading, sharing it with the wider engineering team for feedback and alignment

What we’re looking for

Essential

• Proven experience (often 7+ years) building complex products in diverse teams and environments

• Expertise in React, with a deep understanding of its core concepts

• Track record of building Node.js services, including designing and scaling APIs in production environments

• Comfortable with fast-paced, high-autonomy environments: you’ve ideally thrived in an early-stage startup before

• Deeply curious about AI, and excited to experiment, learn, and harness its potential to transform software engineering

Nice to have

• Real-time collaboration experience, especially with CRDTs (e.g., Yjs)

• Familiarity with block-based WYSIWYG editors like Tiptap or ProseMirror

• Experience building & scaling REST APIs, particularly those conforming to JSON:API

• Production- experience running Remix (or other SSR React frameworks)

• Strong UX & design sense: capable of crafting polished interfaces with minimal design input

• Background in AI products or developer tools

• Comfortable working on infrastructure (e.g., setting up CI pipelines, navigating Kubernetes)

Salary and benefits

We offer a competitive salary commensurate with experience and skills. We provide health insurance which extends to partners and dependents, as well as a pension.

Our office is just a short walk from King’s Cross station. It’s also pet friendly, and we make sure to have regular socials such as team lunches, drinks and more.

We're a hybrid workplace, with the primary in-office days being Monday, Tuesday and Thursday.

Application Process

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

1. Introductory Call with Joe, your potential manager

   A relaxed chat to learn about your background, interests, and career goals. We’ll also share more about the role, Tessl’s vision, and answer any questions you have.

2. Take-Home Exercise

   You’ll receive a practical challenge based on real scenarios you might tackle at Tessl: an opportunity to showcase your approach to problem-solving on your own schedule.

3. On-site Technical Session

   You’ll pair with two of our founding engineers to build on your take-home exercise. This session simulates working together on real problems and allows us to explore your technical expertise more deeply.

4. Culture Conversation with Petra, our People Lead

   A two-way dialogue about our values, team dynamic, and your motivations. Feel free to ask about life at Tessl, growth opportunities, or anything else you’re curious about.

5. Leadership Discussion with Guy (CEO) or Ben (Head of Product)

   Our final stage focuses on strategic alignment and long-term vision. You’ll learn more about Tessl’s roadmap and learn more about 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 care deeply about the warm, inclusive environment we’re building at Tessl and we value diversity – we welcome applications from those typically underrepresented in tech. If you like the sound of this role but are not totally sure whether you’re the right person, do apply anyway!

Learn how we think and work

• On Tessl, The AI Native Development Startup

• Announcing Our $125M Series A for AI Native Software Development

• On the Podcast: Intercom Co-Founder Des Traynor on AI Autonomy & what AI Native means