Allegro, a major e-commerce platform, successfully transformed its monolithic application into a microservices architecture. Along the way, it shifted away from physical servers to a cloud-based infrastructure, which led to a much better developer experience. It also made large investments in tooling and infrastructure to reduce manual work for its engineers. Allegro made sure to allow room for experimentation, but also kept teams accountable for their architectural decisions.

Authorization is complex and creates problems in microservice-based applications. Existing approaches either mix authorization logic with application code (making it hard to understand and update) or centralize authorization data, leading to tough data synchronization. A new service called Oso Cloud solves these issues with policy-based logic and a new distributed authorization architecture, allowing developers to define logic centrally while still using local data to make authorization decisions.

This author is part of a team that built microservices the “wrong way” where everything depends on everything else and thus it's too difficult to make architectural changes. Commenters give their recommendations, such as collapsing the system to an actual monolith if possible and turning remote calls to local calls.