Job Description

As a Senior Software Engineer, you will:

Design, build and ship well-tested features across our platform, with support from more senior engineers.
Take ownership of user stories from refinement through to production and post-release support.
Collaborate closely with Product and Design to understand problems and translate requirements into pragmatic technical solutions.
Write clean, maintainable code and contribute to improving code quality through reviews and refactoring.
Participate in incident investigation and support, helping to improve system reliability and observability over time.
Continuously develop your technical skills and broaden your understanding of the wider system.
Contribute positively to our engineering culture by sharing knowledge, asking questions, and supporting your teammates.
Incorporate AI tools and workflows into your day-to-day development practice, using them to move faster, reduce toil, and raise the quality bar, and share what you learn with the team.

We'd love to hear from you if:

You have experience building and shipping production software as part of a team.

You're confident working with modern backend and frontend technologies (for example Go, TypeScript, JavaScript, Python).

You understand core engineering fundamentals such as APIs, data modelling, testing, and version control.

You enjoy solving problems end-to-end and taking responsibility for your work.

You can communicate clearly with both technical and non-technical stakeholders.

You're happy working in a fast-moving environment where requirements may evolve as we learn more.

You're passionate about AI and actively use AI-powered tools (such as Cursor, Copilot, Claude or LLM APIs) in your development workflow, or you're genuinely eager to build those habits. We care about curiosity and enthusiasm here, not a specific tool or years of experience.

Studies show that women and people from underrepresented backgrounds are less likely to apply unless they meet every requirement. If you don't tick every box but feel this role could be a great fit, we'd still love to hear from you.

We use and teach:

We're passionate about supporting your growth and helping you become confident working across the stack. Depending on the team, you'll have the opportunity to work with and learn:

Go for backend services

TypeScript and React for web applications

React Native for mobile applications

Temporal for workflow orchestration

PostgreSQL for relational data

GCP for infrastructure, monitoring and analytics

AI coding assistants and LLM tooling as part of our engineering workflow

Life at Thirdfort:

Driven by our values, our culture promotes a collaborative and open environment where Thirdforters can take ownership, have impact, and feel empowered when it comes to their growth and development. We understand the importance of our teams wellbeing and recognise a one-size fits all approach rarely works, that’s why we aim to provide the flexibility individuals need to work in the way that suits them, and their families, best.
Our Benefits
We’ve created our benefits package to reflect Thirdfort’s mission and values. We place a strong focus on Security first given what we do, extending this to our team’s physical, mental and financial security to support them through their big life moments. Our benefits exist to empower our team, ensuring they feel supported and able to work in the way that enables them to do their best work.


When you join Thirdfort, you’ll get immediate access to our flexible employee benefits package that aims to support you across these areas:
Compensation - 70k-85k base salary
Flexible Working Hours
Enhanced parental leave
Remote working within the UK only, with optional access to offices in London or Manchester
Annual leave allowance of 26 days, increasing to 30 with tenure and the option to buy additional days
Enhanced sick leave
Private healthcare with our provider, AXA
Regular company and team socials
Uncapped budget for personal development
Share options for all UK employees
Customisable wellness budget and discounts on well-known brands
If you require any reasonable adjustments during the application or interview process, please let your dedicated Talent Partner know and we’ll do our best to accommodate.
We’re committed to building an inclusive, equitable and diverse culture where everyone has a chance to make a difference. We’re purposefully building a team of problem-solvers that reflect our values - which is why we hire from all backgrounds. If you're a curious, kind individual who takes ownership, you'll be a great Thirdforter.