Invoice Koi is one app for iPhone and Android, with the new iPhone Duo to follow. Start the invoice on one, open it on another, and it is the same document: the same lines, the same number, the same PDF.
The whole app: invoices, estimates, clients, the price book, time, expenses and reports, with the PDF drawn on the phone itself.
The same app, not a port of it. An invoice made on Android has the same templates, numbering and PDF as one made on an iPhone.
Planned: closed, the iPhone you know; opened out, the invoice list on one side and the open invoice on the other.
Yes. Invoice Koi is on Google Play, and it is the same app as the iPhone one: the same invoices, templates and PDF.
Not yet. A layout for iPhone Duo is planned, with the list and the open invoice side by side when it is opened out, and when it arrives is still to be confirmed. iPhone Duo goes on sale on 23 October 2026.
Yes. Sign in on both and the same business is on each: clients, rates, the next invoice number and every document. Without an account the books stay on the phone that made them, and a backup file moves them to another.
iOS 16.4 or later. It runs on iPad too, where the list and the open invoice sit side by side.
No account is needed for core invoicing. Sign in for cloud backup, a second device or payment collection. Payments also need Stripe setup. Subscriptions use your App Store or Google Play account.
