There are 3 repositories under billing-software-open-source topic.
A simple GST invoice billing software
Simple Invoicing application for generating Invoice as per India GST Guideline. Visit website http://jujuapps.com for more details
Billing Software is a project which aims to make the process of creating a bill, setting new rates, new tax less frustrating and less stressful. This project has many features which are generally not present in billing software.
GST Billing Software working prototype in Java
Super Market Billing Software is built using Codeigniter Framework of PHP which leads you to easily manage and maintain products and stocks.
Billing Software In Java with Invoice Generation Code in Pdf format
Single Source Of Truth (SSOT) for subscription billing, aggregating transactions and partners through abstract Transaction Gateways and subscriber matching service
Billing Management System
A Open-Source Smart Billing Software. Supported Platform Android, iOS, Windows, Linux, MacOS.
This Project is developed by Uday Kiran Kumar. Hope guys Like it! Enjoy :-)