Zalando’s vision is to connect people and fashion. To do that, we want to get access to potentially all the fashion stock that’s out there in the world. This means connecting to stock from every possible source.

Therefore, stock integration for Zalando is divided into two areas: e-commerce stock, where we connect e-commerce warehouses from other brands and e-tailers, and offline stock, where we connect to brick and mortar stores, digitalise their stock, and make it visible and available online.

The goal of the rebuild

What we’re trying to do is to make every product available for any customer. When Zalando has access to stock sitting in local stores or decentralised warehouses, this enables a broader assortment offering and faster delivery for customers, as well as the potential to offer pick-up of items directly in store, a feature we’re working on via the rebuild of our Merchant Center.

The rebuild will offer a new way to connect our stock partners to the Zalando Platform. It will allow partners to connect to the Merchant Center API directly, or use the Merchant Center frontend in order to upload articles and receive orders manually. The new elements we’re implementing will save time for our partner brands, on top of ensuring better usability of the platform. How does this happen from a technical standpoint?

Under the hood

The major effort of stock integration is connecting the system landscape of brands and retailers to Zalando’s system. On the warehouse side, this is currently achieved by connecting partners via an aggregator (e.g. Anatwine, Tradebyte) that connects the partner’s systems (ERP or Shop System) to their own. For brick-and-mortar stores, the rebuild of the Merchant Center involves Zalando’s Fashion Connector team in Helsinki, who have created customised interfaces to easily integrate existing solutions into our platform.

Our current Partner Program has its technological foundation situated firmly in Java and the SOAP protocol. From an operational point of view, only backend interfaces exist: We have no frontend for external partners to enable them to manage the process themselves, however internal frontends exist to manage them within Zalando.

What we’re planning for our Merchant Center is to replace this with general interfaces that are based on Zalando’s current transition from a shop monolith to microservices. We’ll also be utilising AWS and RESTful architectural styles that incorporate both backend and frontend technologies. AWS simplifies the deployment of new versions of our services, on top of ensuring scalability and easy maintainability.

In the backend, Scala provides a type-safe and performant way of writing services, allowing us to embrace asynchronous computing and build scalable, resilient systems. It is the place where functional programming meets the object-oriented world, making it an excellent tool for solving business-critical challenges.

Together with Scala, we use Akka, the toolkit and runtime for building highly concurrent, distributed, and resilient message-driven applications on the JVM. This gives us an implementation of the actor model – a useful abstraction for building distributed systems. To incorporate RESTful architectural styles, we use Akka-HTTP for building REST APIs, as well as being a performant HTTP layer.

RDS, backed by PostgreSQL, gives us a scalable and managed SQL solution in the cloud, which we use as durable storage for critical data.​

For the frontend, our integration of AngularJS gives us the ability to modularize our code, allowing autonomous teams to maintain and deploy their own modules. We’re also able to use test-driven development practices (TDD), thanks to its built-in dependency injection mechanism.

AngularJS has a big community where we can find ready-to-use plugins and feedback if needed. It’s currently used in conjunction with Typescript and ES6 to enhance the productivity and maintainability of our code.

Benefits for brands and partners

The Merchant Center rebuild will allow us to fully utilise the components of the Zalando core platform, on top of an integration capacity to sell items on different consumer-facing applications such as the Zalando Shop, Lounge, and ZipCart. From a product management perspective, the whole process is currently working in an iterative fashion, where constant feedback loops (based on prototypes and MVPs) and waste elimination is key.

Partner brands will have frontend capacities in the rebuilt Merchant Center, unlike now, meaning that they’ll be able to operate the technological components required to onboard articles and define prices, stock, and their location. They’ll also be able to complete general order fulfilment, customer returns, and everything related to financial processes. This gives brands independence within the platform, rather than relying completely on Zalando to be integrated.

Supporting our partners on a technological level is important, with the end goal for both Zalando and brands being better options for customers. Accessing every possible piece of stock for every potential customer is strengthened by building partnerships, and improving the technological landscape to make it happen.

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