Configuration

Kyushu works out of the box. Each command uses defaults but supports its own optional config file to override them.

The build config typically lives on your local machine and in CI, while the run config lives where you serve your worker.

Note

You can split your configuration across separate files for development and your server, or keep everything in a single e.g. kyushu.toml. There are no strict rules, up to you.

Build

Controls how kyu build bundles and pre-initializes your worker.

Field	Type	Default	Description
input.src	string	src/index.ts	Path to your TypeScript or JavaScript entry point
output.dir	string	worker	Output directory for the built worker
output.file	string	__kyushu_worker.wasm	Output filename for the built worker

[input]
src = "src/server.ts"

[output]
dir = "dist"

Scripts

Run shell commands before or after kyu build. Useful for example when using static assets, to build your frontend app or website beforehand.

[scripts]
prebuild = ["pnpm build"]
postbuild = ["echo done"]

Field	Type	Default	Description
scripts.prebuild	array	—	Commands to run before kyu build
scripts.postbuild	array	—	Commands to run after kyu build

Assets

Controls static asset bundling during kyu build. See the Static Assets guide for setup instructions.

Field	Type	Default	Description
assets.dir	string	—	Directory of static assets to bundle into the worker
assets.precompress	array	—	Compression formats to pre-generate: "brotli", "gzip"

[assets]
dir = "dist"
precompress = ["brotli", "gzip"]

Run

Controls how kyu run loads and serves your worker.

Field	Type	Default	Description
run.wasm	string	worker/__kyushu_worker.wasm	Path to the built worker .wasm file
run.port	number	5987	Port to listen on
worker.mounts	array	—	Filesystem mounts to expose to the worker
worker.mounts[].host	string	—	Path on the host filesystem
worker.mounts[].guest	string	—	Path inside the worker sandbox
worker.mounts[].writable	bool	false	Whether the mount is writable
worker.env	array	—	Environment variables to expose to the worker
worker.env[].key	string	—	Environment variable name
worker.env[].value	string	—	Environment variable value
worker.network.ip_name_lookup	bool	false	Allow IP name lookup (resolving hostnames to IP addresses, e.g. DNS)
worker.network.tcp	bool	false	Allow outbound TCP connections
worker.network.udp	bool	false	Allow outbound UDP connections

[run]
wasm = "build/__custom_kyushu_worker.wasm"
port = 8080

[[worker.mounts]]
host = "./public"
guest = "/public"

[[worker.mounts]]
host = "./data"
guest = "/data"
writable = true

[[worker.env]]
key = "API_KEY"
value = "secret"

[worker.network]
ip_name_lookup = true
tcp = true

Dev

Controls how kyu dev serves your worker during development with live-reload.

[dev]
port = 5987  # default

Field	Type	Default	Description
dev.port	number	5987	Port to listen on
dev.watch	bool	true	Watch for file changes and reload automatically

A custom [input] or [worker] configuration can also be applied; the details are omitted for brevity but follow the same options documented above.