Could Tesco’s revamped application programming interface (API) be the spur for other retailers to encourage third-party developers to build new customer-facing e-tail applications?

Sometimes it takes a market-leading brand to adopt an innovation for others to take the plunge.

They don’t get much bigger than Tesco, so a more public relaunch this week of its API, or application programming interface, could be a watershed moment for the idea that retailers can increase online sales by providing programmers outside their organisation with controlled access to their databases in order to build new consumer-facing applications highlighting their offering.

Encouraging third-party innovation by providing public-facing APIs has become a common approach on the web. They are a key feature of many of Silicon Valley’s current dotcom darlings, from Google on down. The meteoric microblogging service Twitter, for example, recently revealed that just 20 per cent of its traffic came via its own website, with third-party applications powered by its API — like iPhone apps and desktop clients — accounting for 80 per cent.

For retailers, an open API strategy should be a no-brainer. Existing affiliate programmes already encourage third-party website publishers to drive traffic to retailers’ transactional sites. Giving them more advanced tools to create innovative ways of improving these services or rapidly bringing them to new platforms benefits both the retailers and the affiliate. But, with a handful of exceptions — Amazon, eBay and Best Buy have been pioneers — few retailers have taken the leap. R&D head Nick Lansley has been developing the grocer’s API for some time. Last November, the grocer unveiled Tesco @ Home, a desktop gadget built using the API and Windows Presentation Foundation. But now, as Lansley wrote on his blog last week, the API is is being revamped and changes to its terms will allow developers to release consumer-facing applications they have built using the tool.

And Tesco isn’t just taking a “if you build it, they will come” approach; it is taking positive steps towards nurturing a community of outside developers who might be interested in using the API. This week, it invited developers to “T-Jam” , a Tesco “innovation day” to be held at Microsoft’s London offices in early August.

It will be fun to see what innovations spring from a community of developers coming up with new ways to bring groceries to online consumers.

And with any luck Tesco’s success will spur similar approaches to encouraging third-party innovation from Tesco’s retail rivals.