Hemx is checked hypermedia for Rust. Applications render Hemplate views, handle events in typed Rust functions, and return generated UI effects. The browser runs a small effect interpreter instead of a virtual DOM, hydration framework, or client-side expression language. The same core compiles for native servers and server-side Wasm isolates; platform storage, sockets, and lifecycle remain application concerns.

How it works

.heml templates declare page roots, slots, forms, handles, and keyed targets.
hemx-build generates typed Rust helpers from that surface.
#[hemx::handler] functions accept ordinary Rust inputs and return typed effects.
hemx-axum serves pages, assets, handler routes, and effect responses.
The browser runtime validates the build fingerprint and applies effects within the current root.

#[hemx::handler]
async fn add_todo(form: NewTodo) -> impl IntoEffect {
    ui::todos().append(TodoRow::from(form))
}

<form data-hemx-form="new_todo">
  <input name="title" required>
  <button type="submit">Add</button>
</form>
<ul data-hemx-slot="todos"></ul>

Design boundary

Hemx owns checked UI effects and their browser runtime. It does not own routing, databases, authentication, CSS, or application state. Those remain ordinary Rust and web concerns. Browser-specific behavior belongs in explicit leaf islands rather than a second application model.

The normal application path is:

hemx for handler and effect APIs;
hemx-build for generated resources;
hemx-axum for Axum integration;
hemx-js for the browser effect runtime.

Server-side Wasm uses the same core crates and canonical effect batches; it does not require a separate Hemx Wasm runtime package.

Workspace

Package	Purpose
`hemx`	Application-facing facade and handler macro export
`hemx-core`	Effect types, protocol values, validation, and runtime primitives
`hemx-derive`	Procedural macros
`hemx-build`	Build-time template analysis and generated resources
`hemx-axum`	Axum routes, responses, assets, and server push
`hemx-js`	Browser runtime source
`hemx-test`	Test support for applications

Agent skill

The optional idiomatic-hemx skill helps coding agents apply Hemx's generated-resource and server-owned effect model:

npx skills@latest add tmk241/hemx-skills --skill idiomatic-hemx

Development

cargo fmt --all -- --check
cargo clippy --workspace --all-targets --all-features -- -D warnings
cargo test --workspace --all-targets --all-features
cargo deny check licenses sources

htmx helped popularize the HTML-over-the-wire, hypermedia-driven approach that inspired Hemx. Hemx is an independent implementation and does not bundle htmx.

Hemx builds on Hemplate, Tokio, Axum, and the Rust procedural-macro ecosystem. Thank you to their maintainers and contributors.

License

MIT

README.md

Hemx