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Introduction

heph is an open-source build system and task orchestrator. You define targets; heph hashes their inputs, runs each action in parallel in a sandbox, and content-addresses the output. Same inputs, byte-identical artifacts — on your laptop and in CI.

Build once. Trust the cache.

warning

Documentation for deprecated v0 can be found here.

The model in one minute​

A build is a directed graph of targets. Each target declares its inputs and the action that produces its outputs. Before running anything, heph hashes the inputs. A matching digest is a cache hit — heph returns the cached output instead of rebuilding.

BUILD
target(
    name = "server",
    driver = "bash",
    run = "go build -o $OUT .",
    deps = [glob("**/*.go"), "//gen:assets"],
    out = "server",
)
note

Every input you reference — sources, deps, the toolchain — is tracked. If it isn't declared, the sandbox won't see it.

Build it, and watch heph rebuild only what changed:

terminal
$ heph run //app:server
0.565s · 1 / 1 done · 1 cached · 0 failed

Next steps​