I Built a Live UK Electricity Price Dashboard. Here's What Went Wrong (and Right)

I'm on Agile Octopus, where electricity prices change every 30 minutes. Every evening I'd open the Octopus app trying to figure out when to run the dishwasher. The app shows you the rates, but not "the cheapest 2-hour window tonight", which is the thing you actually need to know when you're standing in the kitchen at 8pm.

So I built ukelectricityprices.co.uk. A dashboard that shows live half-hourly prices, finds the cheapest slots for appliances, and compares tariffs across all 14 UK regions. Next.js 16, TypeScript, Tailwind, deployed on Vercel. No database. It pulls live from the Octopus API on each request.

This is the story of building it, including the bugs that cost me the most time.

"The API is free? Seriously?"

The Octopus Energy API is public, well-documented, and doesn't need an API key for tariff data. You just hit https://api.octopus.energy/v1/products/ and you're off. I had half-hourly Agile rates rendering in a table within an hour of starting.