My weekend AI project: AI-assisted search of the UK Companies House database

Just to prove my point on AI assisted product development... As a little weekend project I created https://companychat.uk/ from scratch in net 2 days. That is from idea to a fully functional MVP (not just a demo proof-of-concept), delivering value to the end user. Feel free to give it a go, you get 5 free tokens to play with!

It's an AI aided advanced search tool for the publicly available Companies House dataset. It can help finding leads for all sorts of campaigns and help research by answering questions and prompts such as "How many companies in Brighton were founded by under 30s last year?" or "Give me a list of companies in Bournemouth that will turn 10 years old next month!".

It's hosted on a tiny EC2 instance (£6 per month), connects to an on-premise database server via Tailscale (PostgreSQL with GIS support, hosting Companies House dataset through an ETL pipeline) and to a local SQLite database for system data.

Application stack is FastAPI with Jinja templates for the backend and HTMX + TailwindCSS for frontend rendering.

AI stack: Cursor + Claude Sonnet 3.5 for development, Langchain and Langgraph with gpt-4o-mini for AI assistance.

End to end implemented by a single engineer using Cursor with Claude Sonnet 3.5.