How ASOS devolved integration to scale up for Black Friday


In the midst of a 5-year digital transformation, online fashion retailer ASOS has devolved integration to platform teams as they scale up for Black Friday

ASOS UK website on Black Friday 2017For online retailers, Black Friday is the ultimate challenge as shoppers pile in to snap up bargains. Any systems failure quickly racks up thousands of losses in missed sales, which means IT teams have to be on top of their game. So spare a thought for the crew at online fashion giant ASOS, which is in the middle of a 5-year digital transformation program that brings new challenges every year as Black Friday comes around.

Founded in 2000 to deliver fashion to twenty-somethings, the British online retailer has become a global brand, with annual revenues up 27% this year to £1.7 billion ($2.2bn). It has more than 15 million active customers, who between them buy 300,000 dresses each week. This summer, its sales of wedding dresses alone exceeded 10,000. As sales peaked over the Black Friday weekend last year, its systems processed 33 orders per second.

Just in time for Black Friday

That performance was achieved on an all-new, microservices architecture running on Microsoft Azure PaaS (platform-as-a-service), which the ASOS IT team had brought live in the run-up to last years’s Black Friday to replace the existing 15-year-old platform. This was a significant milestone, but there’s more to come. This year the team has rebuilt its customer-facing web applications. Next comes the replacement of legacy back-office systems, with a final completion date of October 2018 — as always, just in time for Black Friday.

While all of this is going on, the team has a big integration challenge to ensure all the various systems, old and new, continue talking to each other. At the same time, it’s standardizing on new integration tools that replace a hodge-podge of legacy technologies. That’s a big job in itself, says CTO Bob Strudwick:

In our legacy software stack we had every integration technology known to man, so this is a big leap for us.

It has also meant a big change in how IT manages integration. Rather than having a central integration team become a bottleneck, it was vital to devolve responsibility for integration to the various platform teams, says Strudwick.

There was a big cultural change aspect to this. The way you scale is to give individual platform teams cradle-to-grave responsibility.

Devolve integration for scale

The approach taken at ASOS follows the concept of a Center for Enablement (C4E) advocated by integration vendor MuleSoft, whose technology ASOS has adopted for enterprise application integration. Under this model, the integration team defines the standards, best practices and patterns for deploying integrations, and builds common components and the underlying integration platform. Knowledge of how to use these assets must then transfer to each of the seven separate application platform teams, so that they can take full ownership of the integrations they’re deploying and managing to their own stacks.

The C4E works with them to transfer the necessary skills, but if the platform teams can’t independently reliably stand up an integration, deploy code and figure out for themselves any problems that occur, then it creates too many dependencies, explains Strudwick.

The principle of pairing up is the right one, but make sure those teams are operating independently of the integration platform team as early as possible, because then you find out what they don’t understand. It stops the occurrence of trying to be too helpful. A core Center for Enablement platform team cannot do the work of seven program teams. Flushing out the areas where those teams do not know what to do is essential to get things moving forward.

While MuleSoft is doing the heavy lifting of integration to back-office enterprise applications, ASOS is also using the Azure PaaS integration framework for connections between digital applications. A decision will be taken later whether to standardize on MuleSoft for API management or the equivalent Azure capability, says Strudwick.

My take

The roll-out of a microservices architecture implies a move to continuous integration, and therefore it’s essential to disseminate the necessary skills to manage integrations in such a fast-moving environment. This is a big change from previous approaches, but enables a more flexible application framework that can adapt to the fast-moving demands of a modern business environment. Shoppers at ASOS this holiday weekend are witnessing the fruits of that evolution at first hand.

Image credit - Screenshot from ASOS website