Thursday, 20 January 2011

'Grocery-Grazing' Tesco App Customers Get More Respect

Over the past week I have been working with my colleagues to tune the Application Programming Interface (API) service that supports communications from all our apps, now that our TV advertising campaign has brought many new customers to the joy of mobile grocery shopping.

Anecdotal evidence shows that we can support five times the numbers of simultaneous customers using their mobile phones than we could just a few days ago.

It's been a tremendous learning curve to make the communications between the API and our grocery platform as efficient as possible, because customers are behaving differently on their mobile phones than on the web site.

Most customers using our grocery website have sat down to put their full grocery order together. Customers using our mobile phones, however, are 'grocery-grazing'. Throughout the day they are are reminded / inspired to think of a product, pick up their phone, start Tesco Groceries, search for products (or scan them), check the price / offer and, if all good, add to their basket.

We know this because it has changed the 'journey' that our web customers normally make. The main technical consequence is that customers on mobile are constantly authenticating with our servers throughout the day. If you leave the app for more than 10 minutes, it shows 'reconnecting to Tesco' when you start to use it again and re-authenticates (logs in again) with our service.

So I have been working to trim down the steps the API has to go through to login a customer without compromising our security. If encryption and other forms of authentication had to stay (of course!), something else had to give. After much research about the CPU/network/database 'weight' of each login step, we concluded that the API's process to go to a customer's personal details to extract their first name in order for our apps to say, "Welcome (first name)" - with the extra authentication needed to extract it - had to go. This is because it has to take the customer's login details and step through more authentication, network and data hoops to get to their account data. 

In this update, API would use the customer's Title and Surname that had always been available through the cookies provided by our web servers to web browsers.

Tonight, instead of my Tesco Groceries app and iPad Tesco Recipes app saying, "Welcome Nick" it will soon - and rather more respectfully - say,  "Welcome Mr. Lansley".

That API update that will give us five times the throughput that it did before. It's more learning in our new mobile world and one that shows how much more thought I need to put into how the API talks efficiently with our existing grocery platform. 


  1. From what I have seen the app is good, not tried it apart from just adding a few things to my basket, but i have had a customer ask for someone from Dot Com to come and explain how it works to them. They was unaware they needed an account in the first place to use it.

  2. Good to know what's happening behind the scenes Nick. I also heard GS1 UK is helping with the barcoding and product information - hopefully my phone will recognise a greater percentage of products very soon.
    Regarding the API's process being streamlined, I hope it does work in the future with the phone having atleast EDGE coverage, if not basic GPRS.. It now only logs me in via 3G or Wi-Fi, and I'm assuming it's because of the login process..

    Nonetheless, great job with the app, hope it keeps improving the end-user experience!

  3. and how long do the millions of android users have to wait please??

  4. Any idea when this app is coming out for Android OS

  5. Another person who would love news on the Android app here. A mobile grocery site would be also be handy for those of us waiting on the app.


As this blog grows in readership - and because it carries the Tesco brand - I have had to become more careful about the sort of comments that are acceptable. The good news is that I'm a champion of free speech so please be as praising or as critical as you wish! The only comments I DON'T allow through are:

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