API-driven microservices refer to a software architecture approach where microservices communicate with each other and with external systems primarily through well-defined API (Application Programming Interfaces).

This architecture is designed to enhance modularity, scalability, and flexibility by breaking down an application into smaller, independent services that can be developed, deployed, and scaled independently.

API-driven microservices architecture is particularly beneficial for large, complex applications that require frequent updates and scaling. It allows organizations to innovate faster, improve fault isolation, and better align development efforts with business needs. However, it also introduces complexity in terms of service orchestration, data consistency, and network communication, which must be carefully managed.

Key characteristics of API-driven microservices include:

  1. Decoupled Services: Each microservice is a separate, self-contained unit that performs a specific business function. Services are loosely coupled, meaning changes to one service do not directly impact others.

  2. API Communication: Microservices interact with each other and with external clients through APIs. These APIs are typically RESTful, but they can also use other protocols like gRPC, GraphQL, or messaging systems like Kafka.

  3. Independent Deployment: Each microservice can be developed, tested, deployed, and scaled independently of the others. This allows for more agile development and continuous deployment practices.

  4. Technology Agnostic: Different microservices can be built using different technologies or programming languages, as long as they adhere to the agreed-upon API contracts.

  5. Scalability and Resilience: Microservices can be scaled independently based on demand. If one service fails, it does not necessarily bring down the entire system, enhancing resilience.

  6. Focused Functionality: Each microservice is designed to handle a specific business capability, making it easier to understand, develop, and maintain.

  7. API Gateway: Often, an API gateway is used to manage and route requests to the appropriate microservices. It can also handle cross-cutting concerns like authentication, logging, and rate limiting.