Senior / Staff Backend Engineer in London

Capsa is an AI platform that accelerates due diligence and deepens insights for Private Equity funds. We are hiring Staff / Senior Backend Engineers who are comfortable building robust, scalable systems that power our AI platform.

Location: London, UK (Hybrid, In-Person 4 days a week)

Experience: Required: 4+ years

Visa: Unfortunately, we don't sponsor visas yet. You must have the right to work in the UK.

About Capsa AI

At Capsa, we’re on a mission to transform how private capital firms source, analyse, and win deals. Our AI operating system accelerates due diligence, unlocks deeper insights, and helps funds focus on what matters — creating value. We’re lean, ambitious, and obsessed with building a category-defining company. In just 12 months, we’ve grown ARR by 15x, achieved product–market fit with leading multi‑billion‑dollar PE firms, and expanded across the US, UK, and Europe. Backed by top VCs and senior PE execs from Warburg Pincus, KKR, and Goldman Sachs, we’re just getting started.

The Role

A senior backend engineer at Capsa is expected to own projects and features from conception to production, building the infrastructure and services that underpin our AI platform. Key responsibilities include:

• Improving our agent’s capabilities - design and implement new features that endow our agent with human‑level investment expertise.
• Building scalable data pipelines - design and implement systems that ingest, process, and index large volumes of documents and financial data.
• Developing robust APIs and services - create performant, reliable backend services that power our platform.
• Improving connectivity - integrate and incorporate additional data sources into our agent loop, increasing the depth and breadth of the analyses that can be performed.
• Maintaining high code quality - uphold rigorous standards across our codebase, ensuring tech debt doesn’t impede our velocity.

Recent projects include:

• Agentic assistant with a finance‑focused toolkit and advanced document authoring features
• Scalable document ingestion and indexing pipeline
• In‑house, streaming‑first agent framework

As an early stage startup, working at Capsa will be hard work, it will be messy and at times it will be stressful. However, you will:

• Work directly with our founding team.
• Participate in the upside of an ultra‑growth venture.
• Shape the company's vision and will have a direct impact on its success.
• Have the opportunity for fast career growth.

Apply if

You’ll likely be a great fit if most of the following describe you:

• You have 4+ years of experience as a software engineer in a venture‑backed startup or top tech firm.
• You have taken entire products or features from ideation to production and you've measured their impact.
• You have experience with the following technologies (or similar): Python, FastAPI, Postgres, ElasticSearch, RabbitMQ, Redis, message queues, distributed systems.
• You enjoy diving deep into the domain, understanding the problem, and focusing on delivering value to the customer.
• You thrive in a fast paced environment.

Alongside the core role and growth opportunity, we also offer:

• One month per year remote working.
• Budget for setting up your Home‑Office.
• Generous referral scheme (£10k per hired referral).