Invoice Automation Software Python Source Code, Estimate to Invoice Generator with Payment Links and Reminders for Contractors

You finished the work. The invoice is still unsent.

This system builds the estimate PDF, converts it to an invoice, adds a working payment link and sends the reminders that chase it. The reminders stop the moment someone pays.

WHAT YOU GET
Full Python source code, customizable PDF templates, a local database, an estimate builder spreadsheet, complete documentation, sample data and 111 automated tests you can run yourself.

GETTING PAID
Payment links work through Stripe, PayPal, Square, your own page, or plain bank transfer instructions. Through Stripe you also accept Apple Pay, Google Pay, Amazon Pay and Cash App Pay with no extra accounts.

REMINDERS
Email or text through your choice of provider, on the schedule you set. They cancel themselves when an invoice is paid, so nobody is chased for money they already sent.

THE MONEY IS CHECKED
Thirty six of the included tests check only the money, so the payment link asks for the invoice total including tax, never the subtotal and never twice.

WHO THIS IS FOR
Contractors, trades, cleaning companies, consultants, photographers, small agencies, bookkeepers, and any business that quotes in advance and invoices after the work.

WHAT YOU NEED
Python 3.9 or newer. Windows, Mac or Linux. No coding required for normal use. No payment account needed to start.

LICENSE
One payment, no subscription, no recurring fees. Single use license for one (1) business. Client work requires the Commercial License. Not affiliated with Stripe, PayPal or Square.

Everything runs on your machine. Your customer list never leaves it. This is a digital download with no physical item shipped.


Common Questions about the System

Do I need to know how to code?
No. You fill in the included spreadsheet and run one command you copy and paste. Sample data ships with it, so your first branded invoice appears before you enter anything of your own.

Will this work on my computer?
Yes, if you have Windows, Mac or Linux. It needs Python 3.9 or newer, which is free and installs in a few minutes. The documentation walks you through it.

Do I need a Stripe or PayPal account?
No. The whole estimate to invoice flow runs with no payment account at all. Point the invoice at your own page or at bank transfer instructions, and add a payment provider later, or never.

Which payment methods can my customers use?
Stripe, PayPal, Square, a provider you write yourself, or plain bank transfer instructions. Through Stripe your customers can also pay with Apple Pay, Google Pay, Amazon Pay and Cash App Pay, with no extra accounts to open.

Will it chase my customers for me?
Yes. Reminders go out on the schedule you set, by email or text through your choice of provider, and they cancel themselves the moment an invoice is paid, so nobody is chased for money they already sent.

Is this a subscription?
No. One payment and it is yours. No monthly fee, nothing to cancel, and no price rise later.

What if it does not work for me?
All sales are final, because you receive the complete source code the moment you pay. What you can do is check it before you trust it. One hundred and eleven automated tests ship with it and run in about six seconds. Thirty six of them check only the money, so the payment link asks for the invoice total including tax, never the subtotal and never twice.

Where does my customer data go?
Nowhere. Your customer list, estimates and invoices stay on your machine. Nothing is uploaded and nothing phones home.

Can I use this for my clients?
Not under this license. The Single Use License covers one (1) business that you own or operate. Client work requires the Commercial License, which is listed separately.

Is anything shipped to me?
No. This is a digital download. You receive the files immediately after payment.