Future-proofing BSS/OSS: the journey to API-first design

In modern enterprise software, agility is king. Leonardo Hodgson explores the process of API-first design, and how it is bringing integrated solutions to market faster.

Building robust and scalable BSS/OSS solutions demands a strategic approach that goes beyond the usual methodologies to address the complexity inherent in today’s software architectures. On the path from telco to techco, the pace of change is rapid, and systems need to be adaptable to the changing requirements of your business and your users without compromising the software's stability.

This is why API-first design, a paradigm shift from the traditional “functionality first, APIs later” approach, is a game-changer for CSPs. In this model, organisations design and develop feature-rich APIs before the rest of the application. This approach is gaining popularity among software teams because it offers multiple benefits and allows for the creation of consistent and reusable APIs that can be consumed by multiple client and partner applications.

While the “functionality first, APIs later” strategy is still very common, particularly in legacy BSS/OSS systems, its limitations become clearer as businesses expand and evolve. Every integration becomes a bespoke project, demanding significant time and resources to adapt into a clunky and badly designed interface, slowing down the entire development and delivery cycle.

The functionality-first approach is also more expensive, as the same logic has to be duplicated in multiple interfaces or integration wrappers, and it is hard work for the development team to learn and replicate code causing an inferior experience not only for users but for everyone involved in maintaining the application too.

In the API-first approach, the development team works on API design before the rest of the application. Therefore, it often involves additional planning, documentation and collaboration with the stakeholders, providing feedback on the design of each API before any functional code is written, ensuring that interfaces remain consistent and reusable across applications.

Many digital tech companies have adopted this approach with great success, for example Etsy documented its transformation in this blog from back in 2016. However, the telecoms industry has been somewhat slower to transition, bound by legacy software stacks with decades of evolution.

At Cerillion, we recognised early on the opportunity to use the TM Forum Open APIs, a standardised set of industry-specific REST APIs, as part of the modernisation and architectural transformation of our BSS/OSS suite. So unlike other vendors who have strapped Open APIs on to their existing applications, we have redeveloped our product suite using the API-first approach that puts the APIs at the core of the application, enabling consistent functionality across interfaces including self-service portals, mobile apps and external integrations, as well as streamlined product development and maintenance.

An API-first approach to enterprise application development can help organisations achieve their goals by providing a number of key benefits, including:

Faster Time-to-Market
By designing APIs first, developers can create consistent, modular and reusable APIs that can be consumed by multiple applications. This approach speeds up the overall development and release times, and complements a microservices architecture with the APIs serving as standalone features you can plug into any application.

Increased productivity
An API-first development model means organisations can boost their productivity by facilitating quicker cooperation throughout the whole API design and development. Developers have access to common resources including templates, documentation, test servers and other necessities for the team. They also set up consistent processes that enhance the creation, implementation and management of APIs.

Increased agility
APIs can be developed and deployed independently of the client application. This allows for greater flexibility and agility in the development process. It also reduces the risk of issues during integration as bugs and problems are identified much earlier in the lifecycle.

Easier adoption of open standards
When APIs are designed and developed first, the business can introduce new specifications and governance rules in the design and development stage to conform with the chosen standard. This was crucial for Cerillion when adopting TM Forum Open APIs at the core of its product suite.

The limitations of the “functionality first, APIs later” approach become evident as software ecosystems mature – integration struggles, scalability issues and developer frustration grow, directly affecting productivity and innovation.

The ability to easily interconnect multiple different applications and features is crucial in our current connected world, where users have access to different interfaces, platforms and devices to get their job done, and always demand consistent and seamless experiences across them.

Embracing API-first design offers a powerful solution for building scalable, secure and reliable BSS/OSS applications, and firmly propels CSPs on the path from telco to techco.