TallyPro has been developed in the UK by Commercial Software Limited (CSL).

CSL was formed in 1983 by a firm of Chartered Accountants wishing to provide their clients, and other firms of practicing accountants, with specialised software products and services.

A time recording system was one of the first products to be produced, initially for the firm but then marketed to other professional organisations and to clients within the construction industry. CSL has been run as an independent company since 1997.

The time recording product range has been extended over the years both in terms of functionality but also to take advantage of advances in technology such as the advent of the web and smart clients.

CSL has always sold direct to end-users and to date has an installed customer base in excess of 100 sites. A number of these sites, have been customised by CSL using internal features within the products, together with bespoke software and links to external programs. These sites range from single user or small networks to large multi-user real time systems.

More recently, CSL has become a Microsoft Certified Partner and Small Business Specialist, offering installation and customisation of a number of core Microsoft commercial products.