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Introduction

Zeyn is an open source Rust web framework for data heavy applications: grids, forms and workflows. AI agents write the application code. People read it, review it and change it when they need to.

This site is itself a Zeyn app. Every page is Markdown rendered once on the server, the menu on the left is the app menu, and the examples marked Live example are real components running on this server.

What an app looks like

An app is a set of features. A feature holds entities, actions and screens. Screens are rendered on the server; a small runtime in the browser applies changes, so there is no JavaScript to write.

use zeyn::prelude::*;

#[entity(table = "products")]
pub struct Product {
    #[key]
    pub id: ProductId,
    #[rule(required, max_len = 20)]
    pub code: String,
    pub price: Money,
}

#[action(permission = "stock.product.read")]
pub async fn search_products(q: DataQuery, store: ProductStore) -> Result<Page<Product>> {
    Ok(q.apply(store.all()?))
}

#[screen(route = "/products", permission = "stock.product.read")]
pub fn product_list() -> Screen {
    Screen::new(t!("stock.products")).body(DataGrid::of(search_products).column(Product::code).filter().column(Product::price).sum())
}

The same three macros carry the whole language: #[entity] describes data, #[action] is server code with declared access, and #[screen] is a page or a window. The compiler checks that every field, text key and action fits.

Try it

cargo run -p zeyn-example-showcase
cargo run -p zeyn-example-docs
cargo run -p zeyn-cli -- new my-app

The showcase listens on 127.0.0.1:3002 and shows every component with sample data. This documentation listens on 127.0.0.1:3008; set ZEYN_DOCS_SERVER__ADDR to change it.

Finding your way

  • Press Alt+Shift+P to open the command palette. Type a word and it searches every page of this site on the server.
  • Getting started covers the CLI and the structure of a project.
  • Language covers entities, actions, screens, forms, the DataGrid and texts.
  • Components shows each component with a live example next to its code.
  • Guides covers time and languages, security, the API, MCP, data and theming.
  • Reference has the runtime protocol and the architecture.

Principles

  • Performance first. Pages are rendered on the server and streamed as HTML. There is no per user UI state on the server and no client framework.
  • No page reloads. Navigation, windows, language, time zone and theme changes are applied in place.
  • Secure defaults. Every action and screen declares its access. CSRF tokens, a strict Content Security Policy and escaping of user data are always on.
  • One way to do each thing. The language is small, so code written by an agent reads like code written by a person.