We build software that ships — at scale.
Revenant Systems is a UK software consultancy built on twenty years of engineering high-throughput, real-time systems — platforms that process billions of events a month. We work directly with startups, growing companies, and established SMEs where software, data, infrastructure, or spreadsheets have become business-critical. The practice is founder-led: small, senior, and in-house. Quietly. Correctly. On time.
Why teams call us
Something else? Let's talk →- “Our AI feature works in the demo but fails with real users.” AI Production-Readiness Audit →
- “We want an LLM feature in the product and don't know where to start.” AI Feature Feasibility Sprint →
- “Our AWS bill has grown faster than our traffic.” Cloud Cost Audit →
- “PostgreSQL is slow and nobody knows why.” PostgreSQL Performance Audit →
- “We've inherited a system nobody understands.” Legacy Software Rescue →
- “The business runs on a spreadsheet we're scared to change.” Excel Workbook Audit →
- “We need a senior team to build the product properly.” Full-Stack Development →
Services
View all services →AI Consultancy
Practical AI integration — model selection, agent design, and custom LLM features built with the evaluation and guardrails that keep them dependable under production traffic. We also expose your existing applications to LLMs as tools agents can drive, automating workflows that used to take a person.
Anthropic · OpenAI · Google · OpenRouter · Python · pydantic-ai · LMStudio · llama.cppFull-Stack Application Development
Production web applications built end to end — data model, API, and interface. Go, Node.js and Python on the back end; Astro and HTMX for fast, lean front ends. Cross-platform mobile apps in React Native when you need to reach iOS and Android.
Go · Node.js · Python · Astro · HTMX · React Native · ExpoData Engineering & Analytics
The full data path — tracking and ingestion pipelines through to dashboards and reporting systems that turn raw events into decisions.
Python · PostgreSQL · ClickHouse · DuckDB · Data Warehousing · AirflowPackages
View all packages →AI Production-Readiness Audit
A fixed-price audit of an LLM feature or agent before — or after — it meets real users: evals, guardrails, prompt and tool design, cost, latency, and failure modes. From £5,500.
Cloud Cost Audit
A fixed-price audit of an AWS estate's spend — where the money goes, what's over-provisioned, idle, or architecturally expensive — delivered as a severity-ranked report and a prioritised savings roadmap. From £4,950.
Excel Workbook Audit
A fixed-price analysis of the Excel workbooks your business actually runs on — what they do, where they're fragile, and a clear route to fixing or replacing what the audit finds. From £3,950.
Selected work
All case studies →From an SQL reporting bottleneck to auditable answers in Slack
The team behind a UK membership business asks reporting questions in Slack; an agent answers against a read-only copy of the data, every figure traceable to the query behind it.
Have a project in mind? Let's talk.
Get in touchYour message is read by the engineer who would scope the work; the reply is a short technical conversation.