TaxIQ UK
UK income tax and National Insurance worked out across employment, side hustles, rental property, savings and dividends.
App pages →Independent developer · UK
I build iOS apps, small web products and the occasional over-engineered home energy system.
I'm Paul Graham. I make things for iPhone, iPad and Apple Watch in SwiftUI, run a booking platform for independent barbershops and salons, and spend my spare time teaching a Tesla Powerwall to make better decisions with Node-RED.
The work
Most of what I build starts with a problem I've had myself: working out what tax I owe across more than one income, checking industrial IoT events without opening a laptop, or running a small business's diary without a stack of paper. I design, build and ship them end to end.
IIOT Event Management
View, filter and update industrial IoT events and cases from your own Insights Hub tenant, on the go.
App pages →Intimate Activity
A private, discreet log for adults. Built around privacy first.
App pages →TrimBooking
Online booking for independent barbers and salons, each with their own branded booking site and owner dashboard.
trimbooking.co.uk →The hobby
At home there's solar on the roof and a Tesla Powerwall in the garage. The Tesla app is fine, but I wanted the house to react to things on its own: tell me when the battery's full, when the grid goes down, or when it's worth changing the backup reserve before a cheap overnight rate.
So a small Linux box runs Node-RED, which talks to the Tesla Fleet API and sends alerts to my phone over Telegram. Getting Tesla's OAuth working from a home server took longer than building the flow, so I've written up how it fits together.
Toolbox
- Apple
- Swift, SwiftUI, watchOS, StoreKit
- Web
- Next.js, TypeScript, Vercel
- Data
- Supabase / Postgres, REST APIs, OAuth 2
- Automation
- Node-RED, Telegram bots, Linux