Dapr

A sidecar runtime that gives any app portable building-block APIs for state, pub/sub, service invocation, secrets, and actors over HTTP or gRPC.

Category: App Definition & GitOps
CNCF maturity: Graduated
Language: Go
License: Apache-2.0
Repository: dapr/dapr
Documented at commit: 9f2dcfd9 (2026-06-19, near v1.18.1)

What it is

Dapr (Distributed Application Runtime) runs as a sidecar next to your application. Your code talks to the local sidecar over HTTP or gRPC, and the sidecar handles the distributed-systems work: calling another service by its app ID, persisting state, publishing and subscribing to messages, reading secrets, and running actors and workflows. The sidecar binary is daprd and its entry point is a single app.Run() call (cmd/daprd/main.go:21).

The features are grouped into building blocks. Each one maps to a field on the in-memory component registry (pkg/runtime/compstore/compstore.go:42): state stores, pub/sub, bindings, secret stores, locks, crypto, workflows, and conversation (LLM) components. A building block exposes a stable API while the concrete backend (Redis, Kafka, a cloud service) is swapped through configuration.

The single dapr/dapr repository ships both the data plane (the daprd sidecar) and the control plane (operator, injector, sentry, placement, scheduler). On Kubernetes the injector adds the sidecar to annotated pods; in self-hosted mode the CLI runs the sidecar alongside your process.

When to use it

You build microservices in more than one language and want one consistent API for state, messaging, and service-to-service calls instead of a separate SDK for each backend in each language.
You want to defer the choice of state store or message broker to deployment time, swapping Redis for a cloud service without touching app code.
You need the virtual-actor model or durable workflows without writing the placement and persistence machinery yourself.
It is a weaker fit when you only need transparent L7 traffic routing and traffic splitting at the network layer; that is a service-mesh concern, and Dapr does not do it (source 9).
It adds a process per app instance, so an extremely latency- or footprint-sensitive single-language monolith may not benefit.

In this deep-dive

History: origin, milestones, and why it exists.
Architecture: components and how requests flow.
Adoption & Ecosystem: who runs it and what surrounds it.
Internals: the code paths that matter, read from source.
Getting Started: install and a first working setup.

Dapr ​

What it is ​

When to use it ​

In this deep-dive ​

Sources ​

Dapr

What it is

When to use it

In this deep-dive

Sources