Why microservices?

Microservices has become an increasingly popular subject over the last few years. As with any new architectural concept, there is plenty of room for misunderstanding. Even the term microservices is confusing. Newcomers are often unsure about the appropriate size of a microservice (hint: it's not actually about the size of the code base) and can get stuck on how to get started with this architectural style.

Service-oriented architectures are nothing new. Web services were being promoted by various companies in the 1990s as a solution to large, inflexible code bases. The promise was that web services would provide reusable capabilities that could be easily consumed by your code bases. Technologies such as SOAP and WSDL started gaining adoption, but never seemed to deliver on the ease of use promise. Meanwhile, open source languages such as PHP, Ruby, and Python with frameworks such as Symfony, Rails, and Django made developing monolithic web-centric code bases easier.

Fast forward a couple of decades and we started seeing a renewed interest in services. So, what's changed? For one, with the advent of rich web and mobile applications, every system is now a distributed system. Thanks to the advent of cloud computing, compute and storage resources are cheaper than they've ever been. Containers are changing the way we think about deploying and operating our services. Many consumer services are outgrowing their monolithic code bases, and teams are finding them hard to scale. Microservices can help with many of these challenges.