More and more companies nowadays are faced with this very important question, as new and more advanced business applications are emerging: when is it necessary to purchase a new business application? Is it better to modernize a legacy (old) application or put new business systems in place? Legacy system integration can be defined as reusing existing legacy systems and applications by integrating them with newly developed enterprise applications. Legacy system integration provides a non-intrusive method of reusing existing mission-critical applications that reside on legacy systems such as the mainframe or AS/400. Reclaiming these existing resources has many advantages, including reduced risk and significant cost savings.
Certainly, if you are building ecommerce from scratch, then you should consider products as the base of your future ecommerce web application. However, and this is probably your case, in ecommerce scenarios we often see legacy ecommerce portal, which does the job, and your role is to give some impulse as software developer in your IT department to ecommerce integration evolution






