OSAS Business Accounting Software

The most stable Business Accounting Software available

Over 35 years of enhancements, added security, and streamlined operations
at an affordable price.
Cross-Platform Accounting Solutions

Complete Business Management Solutions in a fully integrated ERP System

OSAS gives you the scalability your business needs, and the flexibility to run your business and accounting software on Mac OS, Linux, UNIX, Windows, or any combination of these operating systems. OSAS puts you in charge of your business. With OSAS business accounting software, you get fully-integrated applications that link all parts of your organization and provide you with the real-time, business critical information you need to thrive. You’ll speed your workflow and conserve money when you let OSAS take care of the heavy data lifting with complete ERP systems designed specifically for industry verticals in distribution and construction.

Scalable Accounting

From 5 to 500 users, from 1 to 100,000 products, OSAS adapts to the way you do business. When you choose OSAS as your enterprise resource planning software solution, you do not have to worry about outgrowing your software selection, because OSAS gives you the flexibility you need no matter the stage of growth your business is in today.

Secure Business Software

Consolidating all of your business data in a single system helps establish and maintain access codes, protect data from larger customers and vendors, provide greater control over financial period reporting, and enhance traceability and access to general ledger data generated from other applications.

Streamline Solutions

Profitable organizations run streamlined and efficient operations. OSAS gives your employees the ability to accomplish more with a fully integrated ERP system, eliminating the need for time-consuming double entry of information.

Affordable ERP

At a fraction of the price of traditional business ERP systems, OSAS business accounting software not only gives you modern solutions to your business’ problems, but it provides you with completely personalized solutions to help your business succeed.


  • OSAS is very flexible and allows us
    to do whatever we need to do.
    Carolina Mattress Guild Logo
    Phil Grigg, Carolina Mattress Guild
    100 employees, Manufacturing industry
  • The system handles as large an amount
    as we can put in. It’s very robust.
    Pizza Boys logo
    Norman Sagba Aboud, Pizza Boys
    125 restaurants, Restaurant industry
  • I group data by product or by customer
    or by year. I love that!

    Mancuso Chemicals logo
    Tracy Brewster, Mancuso Chemicals
    100 employees, Manufacturing industry
  • It gives everyone a nice breakdown of all
    the orders entered that day, and no one
    has to do anything to get it.
    Sleeptronic logo
    Alim Sunderji, Sleeptronic
    100 employees, Manufacturing industry
OSAS on mobile, tablet, and desktop

The Technology Behind the Accounting Software

Built using the powerful Java-based BBj language, OSAS includes a full database management system and application development tools. The OSAS framework gives you the flexibility to completely customize your ERP software solution for your business’ industry specific needs.

  • Create functions from scratch
  • Modify screen layouts and forms
  • Customize fields and functions
  • Integrate with existing databases
  • Get real-time reporting and audits
  • Use the SDK and technical resources

Accounting Software for Mac

OSAS is the only mid-market business ERP solution available for users running Mac OS X. Whether you want to run an all-Mac or a cross-platform environment, OSAS gives you the benefits of an accounting software and ERP system, trusted by thousands of businesses, all while maintaining everything you love about the Mac platform.

OSAS running on a MacBook Pro
OSAS runs on Linux

Linux Accounting Software

Open Systems has developed a complete business ERP solution that supports both Linux and Unix platforms, giving you the cross-platform flexibility and freedom to choose the best operating system for your company instead of compromising on your technology choices or heavily modifying an open source ERP accounting package to suit your business.

Why Choose Open Systems?

When you choose OSAS for your accounting software and ERP solution, you can do so with confidence, knowing Open Systems has been supporting businesses for almost 40 years – constantly innovating, enhancing, and most importantly, supporting businesses likes yours every day.