Billing and invoice are the key requirements of every business venture. The feature is incorporated in every other organizational management system such as enterprise resource planning (ERP) solutions or company resource management (CRM) solutions, etc. However, there are tools and software solutions that are solely dedicated to managing the mere billing and invoicing demands of an organization, company, educational setup, or a hospital. Such tools incorporate all the basic features and entities needed to seamlessly handle the organization's (or any firm's) billing and invoicing needs. Key features of a typical billing and invoicing software include the capability to generate customized or standard invoicing, integration with external billing systems such as PayPal, credit card facility, etc., customer details and their purchase history record, import and export capability, and such other features. 

Here at Ibmi Media, as part of our Server Management Services, we regularly help our Customers to perform related Open Source Software Installation queries.

In this context, we shall look into the best software which are free, open-source, and cross-platform compatible, and ensure seamless billing and invoicing of any firm, organization, or company.

1. InvoicePlane

The successor of the previously renowned open-source project called FusionInvoice, the InvoicePlane is one of the best existing free, open-source, and cross-browser compatible invoicing and billing software solutions. The software was released to the market in 2014, and within the period of three years, the software has been acquired by its users by more than a hundred and thousand times from across 196 different countries. Written in PHP and hosted on an Apache server or 'Nginx', InvoicePlane is a web-based application and can support almost every leading web browser. InvoicePlane being a self-hosted open-source application offers a list of numerous features and capabilities, such as customizable application interface, PDF templates, amount formats, email templates, etc., supports CRM-style client management mechanism, the ability for the users to add their contact details, custom fields for project identifiers, and notes, generate an invoice with simple procedures, ability to easily save and apply tax-rates, tracking client payments, ability to translate and support up to 23 different languages, efficient integration with PayPal, and the list goes on.

Get it now from https://www.invoiceplane.com/downloads

2. BoxBilling

BoxBilling is an absolutely and completely free, and open-source billing and invoicing software application. Providing and ensuring a 100% usability score with an intuitive Web 2.0 AJAX interface, BoxBilling also provides the ability to work as a complete and fully enabled client management software. BoxBilling was released to its customers in the year 2011 and since then it has acquired itself a list of satisfied clients. The efficient invoicing and billing software comes equipped with a list of features such as its ability to support automated invoicing, billing, and product provisioning, automatic creation of the hosting accounts after receiving the payment from clients, support for multiple currencies, ability to sell shared and reseller hosting accounts, licenses, products, etc., efficient helpdesk, enhanced knowledge base, announcement, and notifications system, etc. BoxBilling software operates efficiently on Linux and supports MySQL V 4.20 database and is written in PHP. The application works most efficiently and smoothly on a VPS server with APC cache enabled to ensure the best performance and a secured environment.

Get it now from https://www.boxbilling.com/download

3. BambooInvoice

BambooInvoice is one of the best free and open-source software for small-scale businesses or new ventures, independent contractors, and entrepreneurs. Written in PHP 7.x and supporting MySQL and MySQLi 5+, Postgre, MSSQL, SQLite, ODBC, and OCI8 databases, BambooInvoice is structured on AJAX framework. The advanced billing and invoicing software run on a web-based platform and supports all leading web browsers. The software comes equipped with a list of features and capabilities such as its straightforward and easy-to-use user interface that enhances its user experience, built using modern coding standards thereby ensuring efficient running on a secured platform, it stands on one of the excellent web frameworks, i.e., CodeIgniter, secures MIT license, supports and provides translation capabilities for more than 11 languages and the list keeps on increasing every day owing to the efficient and an active community.

Get it now from https://sourceforge.net/projects/bambooinvoice/

4. InvoiceNinja

InvoiceNinja is one of the most desirable open-source platforms for billing, invoicing, and payment management. InvoiceNinja is a cross-platform compatible solution and supports most of the leading platforms such as Linux, Windows, macOS, iPhone/iPad, Android, and all the leading web browsers. InvoiceNinja is an efficient cloud-hosted system and within four years, the company acquired more than sixty thousand satisfied users associated with its wide-ranging software programs and unique applications. InvoiceNinja offers many features and functionalities such as its ability to allow the users to generate real-time invoices and quotations, easy and efficient tasks and projects management and organization, time tracking for completing invoices and bills, support for more than 40 efficient payments option, creates recurring invoices and generates automatic bills, accepts partial payments and deposits, facilitates client logo customized invoice generation and professional invoice template design, features enhanced product library system and unique item list, and the list of features goes on.

Sign up for a free subscription now from https://invoicing.co/#/

5. LogicInvoice

LogicInvoice is one of the most powerful, feature-packed, and straightforward billing and invoicing software. The software is completely open-source solution and comes under GNU General Public License Version 3 making it free to download on all the leading operating systems. It works on the PHP 5.3 version and MySQL Database. LogicInvoice seamlessly manages various users accounts, provides necessary reports for invoices, recurring payments, and accounts, keeps track of bills and invoices that need to be cleared by the customers, creates journal entries, automatically creates one-time and recurring invoices for the customers, supports a multi-language and multi-currency-based system, offers customized email notifications to the users as well as their customers, supports integrated payment gateways.

Get it now from http://www.logicinvoice.com/content/download

6. Invoice Expert

Invoice Expert is a free and open-source invoicing software package that supports any business and company structure. With InvoiceExpert, the users are able to seamlessly and most efficiently send out the billing and invoices to clients and get their approvals. Users can immediately start using the efficient and simple system after installing. InvoiceExpert free invoicing software helps corporations reduce the amount of time spent on administrative tasks as well as reduce overall invoice processing time. The Lite Edition is free to use while the Advanced Edition goes for a one-time fee of $69.95. It supports a list of features such as unlimited invoices, payments, customers, and products, faster and efficient paying system via PayPal integration, ability to most efficiently export and import data to and from Excel, and/or PDF, a customizable and configurable platform enabling logo appending capabilities in the billing and invoicing, compatible with all the leading operating systems, detailed reporting system giving an insight into expenditure and spending, secure and stable cloud-based data backup, efficient notification and alert system, and the list goes on.

Get it now from http://www.invoiceexpert.com/download.aspx

7. Carter

Carter is a free self-hosted mobile-ready invoicing and billing management system built with Laravel PHP framework and Vue JavaScript framework.  It allows companies to manage their expanses, invoices, payments and inventory.

Carter has a simple install wizard, modular structure with several active modules, supports multiple companies, and languages.

It accepts payments through with a seamless Stripe integration.

Get it now from https://github.com/bytefury/crater

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