Senior Software Engineer | AI-Native Startup | £100k+ + Equity | Remote (UK / Europe / UAE)

I'm working with a leading VC-backed AI start-up building production software for legal and professional services teams. The company is approaching ~£1m ARR, backed by top-tier international investors, and is now hiring a Senior Software Engineer to join a small, high-performing engineering team.

This is a hands-on Individual Contributor role for an experienced software engineer who enjoys building end-to-end systems, shipping quickly, and owning production software in an early-stage start-up environment.

The team is small, highly capable, and operates with a strong bias toward ownership, speed, and real-world execution. Several engineers have had opportunities to move into leadership roles but have deliberately chosen to remain hands-on builders.

What they're looking for:

• 7+ years’ software engineering experience
• Strong backend engineering experience (Python preferred)
• Must have early-stage startup experience (non-negotiable)
• Proven ability to own features/systems end-to-end (design → build → deploy → operate)
• Strong engineering fundamentals and product mindset
• Comfortable working in ambiguity with evolving requirements
• Daily use of modern AI tools (Claude, Cursor, Codex, ChatGPT etc.) as part of your engineering workflow
• Evidence of using AI to meaningfully improve planning, implementation, debugging and delivery speed
• Strong bias toward execution, ownership and shipping value
• Desire to remain a hands-on IC (not moving into management)

How strong engineers work here:

• Strong engineers in this team have adapted their workflow for modern software development and use AI as a core part of how they build.

In practice:

• AI tools like Claude or Codex are used heavily during planning and design, before writing code (explicit Claude planning emphasis added from notes)
• Problems are broken down with AI to surface edge cases, risks, and implementation paths early
• The focus is on better thinking and better decisions, not just faster coding
• Writing code is no longer the hardest part of the job, structuring problems and making good engineering decisions is
• Strong engineers use AI to significantly increase output, built on top of strong engineering fundamentals

If you are not already using AI tools as part of your day-to-day engineering workflow, this role will not be a fit.

What you will be working on:

• Owning features from design through to production and iteration
• Building backend systems in Python (FastAPI) and full-stack product surfaces in TypeScript/React
• Working on production AI systems including LLM agents, RAG workflows, retrieval, document intelligence, and tool calling
• Designing and operating asynchronous systems (queues, workers, event-driven workflows)
• Debugging production issues across backend systems, data pipelines, and user-facing product behaviour
• Building reliable, scalable systems with strong attention to failure handling, retries, and data consistency

Tech Stack:

• Backend: Python, FastAPI, asynchronous services, workers, queues, event-driven systems
• Frontend: TypeScript, React, Microsoft Word & Outlook integrations
• Data: PostgreSQL, Redis, document storage, retrieval and indexing systems
• Infrastructure: Azure, Docker, Terraform, CI/CD pipelines
• AI Systems: LLM agents, RAG, tool calling, structured outputs, prompt workflows, evaluation pipelines
• Observability: OpenTelemetry, Langfuse, PostHog, structured logs, metrics, tracing
• Integrations: OAuth, third-party APIs, external platform integrations

Details:

• Salary: £100k
• Equity (0.10%–0.25%)
• Remote (UK / Europe / UAE) - Must have enough overlap with current team

This role is best suited to engineers who have already evolved their engineering workflow for the modern AI era, thrive in early-stage start-up environments, and want to remain deeply hands-on while building high-impact systems.

If you're a strong builder who uses AI as part of how you already work and want real ownership in a fast-moving start-up this will be a strong fit.

If this sounds like you, apply direct or email your CV to Zoe.hinkinson@propellondon.com