Dapr

Dapr (Distributed Application Runtime) is an open-source, CNCF graduated runtime for building microservices, event-driven systems, and AI agents without hand-rolling the same distributed-systems plumbing in every service. It runs as a sidecar alongside an application and exposes building blocks - service-to-service invocation, state management, publish/subscribe messaging, workflow orchestration, and secrets - over standard HTTP and gRPC, so any language can use them without a Dapr-specific SDK, though native SDKs exist for .NET, Java, Python, Go, JavaScript/TypeScript, and Rust.

Because these capabilities are accessed through Dapr's APIs rather than baked into application code, the underlying infrastructure - which message broker, which state store, which secrets vault - can be swapped through configuration without changing application code, and the same building blocks work consistently across Kubernetes, other clouds, the edge, or a local machine.

Dapr is a fit for teams building microservices or event-driven backends who want distributed-systems primitives as infrastructure rather than reimplementing them per service - a different abstraction level than the backend-as-a-service platforms elsewhere in this catalog like Supabase or Appwrite, which provide an opinionated backend with its own data model rather than unopinionated building blocks a team wires into its own services.