Tesco.com is a UK e-commerce success story. Although a helping hand from a parent company with a £14bn turnover last year undoubtedly helped it weather some of the early turbulence that has drowned other fledgling dot-coms, Tesco.com's smart attitude to technology has also been a major differentiator. Testament to this is that US grocery chain Safeway has licensed its whole Web front end.
Instead of getting buried in overheads building expensive warehouses like the competition did, Tesco focused on a cost efficient programme to base its Web strategy around existing logistics and pick products directly from its network of 720 UK stores.
And it is this cost efficient approach that has seen the company explore the write-once, use-on-multiple-platforms benefit of Web services. Allying itself closely with Microsoft's .Net platform, Tesco.com has overhauled the entire structure of its site to take advantage of emerging access devices such as PDAs.
"Tesco.com found itself in a position where it was producing multiple and essentially redundant pieces of code to facilitate multiple platforms. Our reuse was really poor; we implemented many solutions to the same problem," says Jon Higgins, Tesco.com head of e-commerce development.
"What we decided a while ago was that we wanted a model that would support multiple clients, affiliates and our own Web site, which all had requirements for the same kind of data," he adds. "We could implement the Web service once and then the Web service would be ultimately reusable by any of those clients and indeed anything that happened in the future."
Tesco.com took around a dozen business objects, such as customer log-in, check-out, "show me" promotion and exposed them as Web services and configured their clients to use them.
Higgins claims that maintenance overheads are much lower as a result and the consistency of information is better; it eliminates the possibility that you are giving different information to different clients because they are all using the same service.
Code written as a Web service is also being used for another unique platform. Conscious of the need to keep connection costs down for a customer base mostly surfing via dial-up, Tesco.com has developed an offline client that allows users to update their shopping lists offline.
The importance of this offline client to Tesco.com could be seen as one of the main reasons that it has decided to go with a complete Microsoft approach to Web services. Opting to use the Web technology of a company that practically owns the desktop must help when it comes to getting Tesco.com's offline client, and Web site in general, to perform efficiently in the Windows environment used by the vast majority of its customers.
But Higgins claims the decision to go Microsoft was one based on cost and efficiency. "Microsoft's dominance of the desktop and PocketPC didn't influence our decision at all. Our decision to go Microsoft is purely based on the fact it's the most cost effective and quickest development tool," he claims.
"Once you are using one technology, you are less likely to change, because change usually puts you back while you accommodate the change. But saying that, if there was a good financial or function cause for us to change then we would."
"We've looked at using other database and development technology and Microsoft is definitely the best return on investment for us. We have been very profitable and I think if we converted it would cost us so much more to do the same thing without question."
But Higgins concedes that the .Net concept was pretty confused for a while, with Microsoft reticent to commit to anyone of the myriad early definitions of what Web services were. "I think it is clearer now. It felt like a global term for everything. Everything released in 2002 was something .Net."
Tesco.com was also on the early adopter programme for Windows Server 2003 but apart from the inherent speed increase, which Higgins says is not to be downplayed, there haven't been any major functionality advantages in the move.
"We were running a 2000 server with the .Net framework on top and there isn't much difference there in terms of functionality. But in terms of speed, the kernel mode Web server is hugely quicker," he explains.
But despite the faster server platform and a clearer vision of the realities of Web services, Higgins claims current deployments -- including his own -- are still in their infancy.
"A lot of people have implemented Web services in a local or known way. Ours are very much between our own clients and know affiliates to us," he says.
The nirvana of Web services, according to Higgins, is to the full Universal Description, Discovery and Integration model (UDDI). UDDI acts a registry and locator service for Web services; applications access UDDI directories automatically, in the background, to find the information they need to complete transactions.
"Everyone can look them up and find them as they want almost without the owner of them knowing they are doing it. Which would be a good thing but I haven't seen any implementations that have got there yet."
"I'm interested to see where the whole UDDI model goes with Web services. I think they have gone as far as they can get now until some real killer type UDDI apps appear and I haven't seen any yet," he says.
Although Higgins claims UDDI is the key for business to business Web services he is less enthusiastic for its potential in the business to consumer space.
"If you're a car supplier and you want to buy a few hundred wheel nuts, using UDDI to find a service to allow to buy them from the cheaper supplier makes sense; but in terms of business to consumer I don't think you want to get your lemons from Tesco, your oranges from Safeway and your bananas from Sainsbury's just because those sites happen to give you the best price or convenience."
Find out more about Web services in this IT Priorities Special Report: