Top Free and Open Source Invoicing and Billing Software

Top Free and Open Source Invoicing and Billing Software

It is easy to prepare a simple document with the word processor or spreadsheet but to keep the track of payment and receive reminders to follow up the invoices, you need an application. You can view the invoices that are sent through the Invoicing Software and billing software. 

Top free and open source invoicing and billing software are: 

Simple invoices

  • Simple invoices are open-source billing software that facilitates the recurring preparation of managing multiple customers, sales reports, recurring payments, and a variety of other payments. You can install it yourself, in case if you need any help you can contact the developers. Send invoices, track finances and bills, and do many more from the Linux, Windows, or IOS device. 


  • Export data to various formats: PDF, Excel, MS Word, or plain text format. 

  • Create multiple invoice types such as a total invoice or itemized invoice. 

  • Multiple template options. 

  • PayPal integration

  • Selection of layouts 

  • Efficient payment tracking. 

  • Various languages. 

  • Unlimited invoicing


  • This is a free billing software for businesses and service providers. It consists of excellent tracking and cloud storage as well as backup. It provides a simple user interface with easy invoice creation. It supports multiple users and is suggested for small and medium-sized businesses.


  • Strong and secure with easy editing in products, services, and databases. 

  • Easy management of reports and invoices with easy to print options. 

  • Support multiple currency locations depending on the location. 

  • Built-in Invoicing software updates to have the current and secure version. 

  • Support creating and sending reports and invoices in a PDF manner. 

Sleek Bill Visit Website

  • It is one of the top free invoicing software in India with the best invoicing features making it ideal for freelancers and small businesses. It allows the users to create customized invoices and in different formats such as PDF or Excel.


  • Easy to create and send estimates to the clients. 

  • Easy to add data or edit data from the database. 

  • Automatic backups to the local file that is easy to retrieve. 

  • Features for appending the brand, logo, and any other particulars to the invoice. 

  • The invoicing software comes with preloaded data for tax. 

  • PayPal integration for prompt payments. 

Invoice Expert

  • It is billing software that lets to send billing estimates to their clients for approval. It is easy to use and takes minimal time for installing. It reduces the time spent on administrative tasks as well as the overall processing time of the organizations.


  • Unlimited tag: unlimited payments, products, invoices, and customers. 
  • Seamless PayPal integration with faster payments. 

  • Easy exports of the data to PDF or Excel or importing data from Excel through the inbuilt data import wizard. 

  • Easy customization allows appending branding or logo to have a professional output. 

  • Compatible with the latest operating systems. 

  • Detailed reports of the earning and expenditure. 

  • Stable and secure backup at cloud storage. 

  • Sending SMS notifications regarding work and invoices is a plus. 

Invoice Ninja

  • It is a powerful software with invoicing as a primary function and loaded with various other features. Being open-source software, the functionalities it provides are commendable. With hefty functionalities, it may be the first preference in open-source software.


  • Integration with more than 40 payment gateways. 

  • Real-time invoice creation. 

  • Google analytics support. 

  • Professional quotation and invoice templates. 

  • Time tracking tools. 

  • Automatic conversions of currency


  • It is a perfect software for small businesses. It allows us to create professional and elegant invoices within a few minutes. It takes the estimates in a smooth and effortless flow. The invoices can be in any of the currency for the customers. They also can pay directly on the invoice.


  • Convenient dashboard with the activity log. 

  • Monthly and yearly financial reports. 

  • Unlimited invoices. 

  • Customized invoices and recurring invoice accounts. 

  • Customizable icons, statements, and logos. 

  • Automatic reminders. 

  • Track expenses, billable hours, and miles. 


  • It is a self-hosted software to manage invoices, quotes, clients, and payments. This billing software has garnered more than 12000 users across 150 countries. It was built with the intention of providing billing, invoicing, payment, and client management.


  • Easy to customize. 

  • Multi-lingual supporting 23+ languages. 

  • Easy invoice creation. 

  • CRM makes it easy to manage customers.

  • Prepare and send quotes with a single click. 

  • Easy to keep track of payments

  • Easy integration with PayPal. 

Bamboo invoice

  • Being an independent contractor, Bamboolnvoice is one of the best choices. The easy-to-use and simple interface provide easy access even to a non-tech person. 
  • Create and edit invoices along with tracking through the client numbers. The system gives notifications for the pending invoices and also sends email invoices or generates PDFs. 


  • Available in 11+ languages including English, French, Spanish, Dutch, Romanian, German, Swedish, Bulgarian, Portuguese, Estonian, Italian with increased languages in each update. 

  • Easy to use and active in the industry.

  • Functional systems build on modern coding standards. 

  • Compliant with the web browsers and support all the modern options. 


  • This billing software offers various pre-designed templates for billing purposes and with customizing options. It allows invoice creation in multiple currencies along with calculation of profit in own currency. 
  • It automated invoicing, billing, and product provisioning. Order gets suspended automatically if payment is not received till the due date. It is powered by an Intuitive Web 2.0 AJAX interface that provided a 100% usability score. 


  • Allows accepting one-time and recurring payments in different currencies. 

  • Allows sharing shared and reseller hosting accounts, software licenses, recurring billing products as well as downloadable products. 

  • The Billing software can be configured to send payment reminders until it is terminated. 

  • Integrated helpdesk to communicate easily with clients. 


  • This Billing software gives full access to the code. The code can be customized to suit the business needs. It is specially designed for small and medium-level enterprises and agencies. It supports Windows as well as web platforms.  
  • Users get full control over the calculation and presentation of invoices. Template generators allow us to design every element of the invoice. Maintain numerous formats with easy to update interface. 


  • The system facilitates accurate billing with customized invoice presentation and flexible delivery. 

  • It can be easily deployed over cloud platforms. 

  • Multi-language and multi-currency support. 

  • Automatic payments collection.

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