Senior Software Engineer (AI Systems & Tax Advisory Platform) - London

Software Engineer - London

£80k base + meaningful EMI equity

About Revax

Revax is a new class of AI-native software for tax advisory teams. Today, advisers lose entire days to researching and drafting advice - fragmented knowledge, manual workflows, and brittle tooling. We turn a firm's own expertise into structured, transparent AI systems that draft, analyse, and explain deliverables with full traceability.

We're a seed-stage startup, with backing from leading institutions, angels, and tax industry leaders. We work with major firms; the team is small, technical, and shipping fast.

The role

We're building out our engineering team to allow us to onboard more firms, and to help us build the leading tax research platform faster. You will work directly with the founders, owning features end-to-end across the stack, and helping to define how AI systems are built responsibly in regulated domains. Customer calls, prototyping, production hardening, and the work that lets us sell into leading firms - all of it is in scope. If you enjoy designing clean APIs, scaling services, and shipping products to paying enterprise customers, this role is for you.

What you'll do

•             Model and optimise PostgreSQL / Supabase & graph db / Neo4j schemas for complex data

•             Design and implement APIs in FastAPI for AI workflows and product features

•             Build and scale LangGraph-based multi-agent systems with checkpointing, retries, and observability

•             Integrate vector search, knowledge graphs, and retrieval pipelines into production services

•             Deploy services on GCP (Cloud Run / GKE) and improve performance, reliability, and cost

•             Implement the auth, IAM, audit, and access-control patterns enterprise customers expect

•             Help deploy SSO, tenant isolation, auditability, and the security reviews that come with selling to major firms

•             Work with customers, other engineers, and the founders to create best in class software

Who we're looking for

Essential

•             2–3 years building production software

•             Experience with LangGraph, RAG pipelines, vector databases, or knowledge graphs

•             Production experience with FastAPI or a similar modern Python framework

•             Experience scaling and operating services on GCP, AWS, or Azure

•             A high-ownership mindset - you care about reliability, correctness, and outcomes, not lines of code

•             Heavy use of modern AI coding tools (Cursor, Claude Code, Codex)

Strong plus

•             Experience with any of; multi-tenant deployments for enterprise customers, VPC networking, Kubernetes, or shipping into procurement-heavy regulated buyers.

•             Exposure to Neo4j or graph-based data modelling

•            Working knowledge of LlamaParse/LlamaIndex

•             Experience optimising low-latency applications

•             Time spent on AI-native or agentic systems in production

Nice to have

•             Exposure to professional services, finance, tax, or other regulated domains

•             Strong instincts for developer experience and internal tooling

The package

•             £80k base + meaningful EMI equity

•             London-based, with a strong preference for in-office

•             Visa sponsorship available

•             Modern stack, and driven team that you can get have an impact in from day 1.

If this sounds like you, please apply.