See also: API Design Cheat Sheet, Platform Building Cheat Sheet

Microservices Cheat Sheet

1. Do only one thing and do it well. The "one thing" is defined by a "Bounded Context" in Domain-Driven Design (DDD).
2. Own your own data. No shared data stores.
3. Embrace eventual consistency.
   • Don't read your writes.
   • Publish your own state-changes (minimally) to an event log.
4. Leverage event logging and/or streaming to replicate and denormalize data from other services.
   • The event log must be subscribable to publish events to subscribers.
   • The event log must be durable and must not lose messages for publishing and replay.
   • Examples: Kafka, Confluent.io, Amazon Kinesis.
5. When aggregating microservice calls, use asynchronous, non-blocking I/O. Perform as much as possible asynchronously.
6. Support a registry/discovery mechanism.
   • Examples: Consul, Eureka
7. Support Location Transparency.
   • Support statelessness--no sticky sessions.
8. Support the use of back-pressure (see, Reactive Streams specification) to avoid cascading failures.
   • Examples: RxJava
9. Support the Circuit Breaker pattern to manage faulty service dependencies.
   • Examples: Hystrix, Apache Zest
10. Consider CQRS to scale reads separately from writes.