In this article we will see benefits that API-led connectivity approach brings in the process of composing our business platform.
API technology is one of the key factors in the process of digital transformation. Let’s take mobile and cloud system as an example. At the beginning, they were treated just as a trend which will support current business processes, but today they are both key factors in daily work tasks when achieving biz goals.
Similar to that, API once treated as a tool for developers, today represents the way of connecting which companies can use to expand themselves on new marketplaces or to build new partnerships.
This way of connecting is not simple and it requires several different technologies to work together. But, we can benefit from the advantages that API connectivity offers and grant ourselves a relevant place on the market by extending our platform to the channels where our customers expect us the most. In this process, API-led connectivity approach can be of great help to us.
What is API-led connectivity approach
API-led connectivity approach is a methodical way of connecting data with applications through reusable and purposeful APIs. This approach changes the way IT operates and promotes decentralized access to data and capabilities, while not compromising on governance. API-led connectivity approach defines an operating model that can help us to organize our assets. It can help us to plan who should own those assets and what their roles will be. 
By accepting the API-led connectivity approach, we can build our own network of applications or integrate our existing platform into third-party software. We can also become more agile and react quickly on market changes. Being able to meet all the requirements of our customers, we can build stronger connections with them.
One research states that in Germany 58% of consumers would consider changing retailer due to a disconnected experience. 
The API-led connectivity paradigm
Business platforms have complex, interwoven connectivity needs between their components. To develop one with the help of API-led connectivity approach we can rely on the three-layered model that this approach suggests.
According to that we can have the abstraction representation of every part of our platform as a stand-alone API. Grouping them into multilayer architecture we can achieve agility and flexibility. Three layers are: System Layer, Process Layer and Experience Layer. They open up data, model processes and help us define innovative customer experiences.
“Three-layered” API-led connectivity architecture. 
System APIs are usually used to access the core system of records. Often these systems are not easily accessible due to connectivity concerns or because of architectural differences between them and their consumers. Those APIs should provide the means of hiding that complexity from the user while at the same time enabling the access to this data.
Process APIs shape the data according to the business requirements. To achieve component reusability their implementation have to be encapsulated independently of the source systems, from which their data originates, as well as the target channels through which that data is to be delivered.
Experience APIs provide the means by which data can be most easily consumed by its intended audience. All the data that has been sent from our platform to the outside world originates from a common data source, which gives us great consistency. Experience APIs should be created following the API-first design principles. There are three principles of API First Design:
1. Our API is the first user interface of our application.
2. Planning of our API comes first, then the implementation.
3. Our API is described (and maybe even self-descriptive, through hypermedia). 
Those principles can be achieved with the use of API description languages (i.e. OpenAPI Spec. or RAML). Characteristic of those languages is that they are both human and machine readable, which makes them very suitable for writing specification which will determine how our API will operate.
Benefits of API-led connectivity
Business benefits that API-led connectivity offers are numerous. For example, we can expose our data as a service to our customers. Through a self-discovery, we can increase the visibility of our platform. Also building a system that is not tightly coupled but service-oriented allows us to divide programming logic between the components. It gives developers an opportunity to use the same component in different applications, which reduces effort and increase productivity. By creating the modular system we are able to better estimate and ensure delivery against changes to the code. This architecture negates the nightmare scenario of a small database field change having a significant downstream impact, and requiring extensive regression testing.
In addition to the business benefits, there are also great technical advantages. Detached levels of APIs offer different levels of managing and control on each of them. This allows us to plan carefully and introduce slow changes in our core system of records, while at the same time we can be very flexible and introduce quick changes in the parts which are faced to our customers (mobile and web touchpoints).
Most important are advantages for our customers that we can offer. API-led connectivity concedes us to be highly adaptable on ever-changing demands. Today’s clients are using various channels and devices to acquire almost anything and expecting flawless and personalized experience during that process. With good integration between our in-store and online software, we are able to offer one uninterrupted experience wherever buyers are.
The exponential rise of API-based companies is a reflection of modern businesses looking for new ways to make use of their data, connect their systems and create great experiences for their customers and gain a competitive advantage.
 First, Break IT. Edited by Ross Mason. MuleSoft, Inc.
 MuleSoft Connected Consumer Report, 2017.
 Three Principles of API First Design by Lars Trieloff.