giolt

Build, run and deploy Gleam apps on Giolt.

Add it as a dev dependency and run it. It works on Node 20 or newer, which is Gleam’s default JavaScript runtime, and on Bun:

gleam add --dev giolt
gleam run -m giolt build
gleam run --runtime bun -m giolt build

Your entry module exports one function named handle:

// JavaScript target
pub fn handle(req: Request(conversation.RequestBody)) -> Response(conversation.ResponseBody)

// Erlang target (GlowVM)
pub fn handle(req: wisp.Request) -> wisp.Response

giolt build checks this signature against gleam export package-interface and fails with the expected and found types when it does not match.

Commands

Command	Does
`giolt build [--config FILE]`	Checks `handle`, compiles and bundles into `outdir`
`giolt dev [--config FILE]`	Builds, watches `watch`, serves on `port` and reloads on change (JavaScript target)
`giolt deploy [--preview] [--artifact DIR] [--config FILE]`	Builds, then uploads `outdir` to Giolt (JavaScript target). With `artifact`, uploads that directory instead

deploy reads the token from GIOLT_TOKEN. GIOLT_API_URL overrides api_url.

Configuration

Everything is optional and lives under [tools.giolt] in your gleam.toml, or in the TOML file you pass with --config FILE when one package needs several builds (the package name and target still come from gleam.toml, and keys the file leaves out take their defaults):

Key	Default	Meaning
`entry`	your package name	Module that exports `handle`, such as `my_app/server`
`assets`	none	Directory of static files, copied to `outdir/static` and served by `dev`
`outdir`	`"./dist"`	Where the bundle goes. It is deleted before every build
`esbuild_args`	`[]`	Extra esbuild flags, appended after the fixed ones so they win
`spa`	`false`	Serve `index.html` for paths that match no file (static-only apps)
`watch`	`["src"]`, plus `assets`	Directories `dev` watches
`port`	`3000`	`dev` server port
`live_reload`	`true`	Reload the browser after a rebuild
`api_url`	`"https://dash.giolt.com"`	Giolt API used by `deploy`
`prebuild`	none	Shell command run before every build, such as `gleam run -m docs/build`
`artifact`	none	Deploy this directory as a static site. Skips the `handle` check, the compile and the bundle

Erlang target

A project with target = "erlang" builds for GlowVM. You need Erlang/OTP and rebar3 installed, and giolt build tells you which one is missing. The output in outdir is app.avm plus the runtime files (glowvm.wasm, index.js, index.min.js). dev and deploy do not support this target yet.

Issues

Report bugs and requests at github.com/withgiolt/issues.