How Dagger Works

Before you design a module, learn the world it lives in.

Dagger has a simple shape:

1. A workspace is the project using Dagger.
2. A module adds capabilities to that workspace.
3. A function is the typed action a module exposes.
4. The engine runs the work as a graph.
5. The cache makes repeated work fast.
6. A check turns a function into project validation.

That is the core model. Everything else in the Module Developer Guide builds on it.

Learn It in This Order

Read these pages in order:

• Workspaces: where Dagger starts.
• Modules: what a workspace installs.
• Functions: what callers run.
• Checks: how modules protect a project.
• Cache: why good modules feel fast.
• Execution: what happens under the hood.

Do not rush this. Most bad module APIs come from skipping one of these ideas.

What This Unlocks

Once this model clicks, module design gets much easier.

• You know what belongs in workspace config.
• You know what belongs in a module API.
• You know why functions return typed objects.
• You know why checks are different from tests.
• You know how cache rewards precise inputs.
• You know why Dagger works the same locally, in CI, and in Cloud.

Start with Workspaces.