Senior Product Engineer (Full Stack) London

We are seeking an enthusiastic and ambitious Senior Software Engineer with a keen eye for quality to join our growing Engineering function. You will be joining our Payments squad, responsible for building out our cross‑market flexible Payments capability. This is a team which has recently transitioned to being “LLM‑first” in their working style, so you would be joining at a critical moment to shape our ways of working and our approaches to LLM‑based tooling.

In this role, you’ll get to:

• Design, implement and deliver software features with full ownership from start to finish.
• Collaborate as part of a close & multi-disciplinary team. Your work will have meaningful and measurable impact on our organisation and products.
• Own business‑critical components and ensure their stability and maintainability.
• Mentor other members of the team to ensure technical excellence and continuously raise the bar when it comes to engineering standards.
• Share your ideas with the team and build products that make an incredibly impactful difference to society and people’s lives.

Ophelos Tech is an AI‑first technical organisation, and effective use of LLMs are central to how our Engineers work. Claude Code, Codex, and OpenSpec are critical tools in our toolbox. The right person for this role should be excited and motivated to work in this AI‑first world.

Stack-wise, we run TypeScript, Python, and Ruby at various levels in our stack – for this role we are really seeking a polyglot Software Engineer for whom specific implementation language is not critical. Elsewhere in our stack, we make use of:

• the FastAPI web application framework.
• PostgreSQL (via PlanetScale) as our application‑level data backend.
• Databricks as our “data lakehouse”.
• Temporal for workflow automation.
• Claude Code for LLM‑first Software Engineering.
• OpenSpec for LLM‑powered specification‑driven development.
• AWS & Kubernetes as our cloud‑based infrastructure platform.
• Ruby & Rails powering our legacy application.
• TigerBeetle to power our financial ledger.

Ophelos Tech operates hybrid working, and believes face‑to‑face working time is essential for planning and alignment. Our teams spend two days each week working in-person from our comfortable office near Liverpool Street in London.

About you: More than anything we are interested in your general experience as a software developer and your approach to solving problems, however, some experience in the following is important for this role:

• You should have at least 5 years of experience in Full Stack Engineering.
• Experience with TypeScript (or Python, Ruby or other similar high‑level language).
• You enjoy learning new technologies and are passionate about experimenting to figure out how to build things in a better way.
• Experience and enthusiasm for using the latest LLM tools – Claude Code, Cursor, Codex is critical, as is the intent to continue developing your skills using agentic LLMs as the software engineering landscape continues to develop.
• Attention to detail, intellectual curiosity & a willingness to embrace the changing technical landscape we find ourselves in.
• An understanding of web programming & familiarity with web frameworks e.g. FastAPI, Ruby on Rails.
• You are excited about Ophelos’ mission to support households and businesses to break the vicious debt cycle.

Ophelos is committed to creating a diverse work environment and is proud to be an equal opportunity workplace, providing equal employment and advancement opportunities to all team members. We are building an environment where every Ophelos team member can thrive, feel a sense of belonging, and do the best work of their careers. We value diversity and recruit, hire, and promote individuals solely based on talent, qualifications, competence, and merit. We evaluate candidates without regard to race, colour, religion, age, sex, sexual orientation, gender identity, national origin, disability, or other protected characteristics as required by law and as a matter of our company values.