InvoiceKoi

About the tool

InvoiceKoi is a mobile invoicing app built for self-employed tradespeople and small service businesses such as electricians, plumbers, builders, cleaners, and mobile mechanics. Users pick a saved client, tap rates from their own price book, and send a professional PDF invoice by email, WhatsApp, Telegram, or Messages, choosing from nine templates with their logo and colours. Quotes can be signed on the phone and turned into the invoice in one tap, and the app tracks every document as sent, opened, part paid, paid, or overdue. The app focuses on doing the paperwork on site rather than at the kitchen table. Core invoicing and PDF creation work offline with no account, while Koi Pro adds AI features: a receipt scanner and Read a photo feature that use a vision model (DeepSeek) to pull the merchant, amount, tax, and category from a picture, voice-to-invoice that turns a spoken note into a draft, and a tool that answers questions about a document. Clients can pay by card or bank through a Stripe link, daily alerts flag overdue invoices, and reports show income, tax, and hours with CSV, spreadsheet, and PDF export. InvoiceKoi is aimed at sole traders in the US and UK who find paper too little and field service software too much. Setting up and drafting is free, and sending invoices requires Koi Pro at $9.99 per week or $99.99 per year on the US App Store, or £9.99 per week and £99.99 per year in the UK, with free trials for eligible new iOS subscribers. It is available on Android now, with the iPhone app in App Store review.