A new experimental templating library called zt is bringing typed, compile-time HTML generation to Zig applications. Developer Peter Lalik described the project as an adaptation of Go’s Templ approach: templates are parsed during `zig build`, converted into Zig source and imported directly by the application. That design allows templates and application code to share types rather than exchanging loosely structured values at runtime.
The generated renderer writes to Zig’s standard I/O writer abstraction. An application can stream output to a socket or collect it in a buffer, and the rendering path is designed as a sequence of writes without additional allocations. Lalik developed zt while working on the zio and Dusty libraries, which target API backends and web applications.
Type checking is central to the proposal. Template parameters can use application-defined types, so a misspelled field or an incompatible argument becomes a compiler error. The generated source includes comments pointing back to locations in the original template, helping developers connect a Zig diagnostic with the markup that produced it. Components can be passed as values, and an `@children` mechanism supports layouts that wrap other templates.
The library also provides defensive defaults for dynamic content. Values inserted into text or attributes are HTML-escaped automatically. Values placed in URL attributes such as `href` and `src` are checked for dangerous schemes, while raw HTML requires an explicit syntax. Elements must be properly closed, preventing one common class of malformed output. These measures do not eliminate every web-security risk, but they make potentially unsafe operations visible in source code.
Control flow uses Zig constructs including `if`, `for` and `switch`, with payload captures available inside templates. The current syntax has an acknowledged ambiguity: a line beginning with one of those keywords is treated as code, meaning ordinary prose that begins the same way can cause a parse error unless it is wrapped or expressed differently. Lalik is considering prefixed forms such as `@if`, `@for` and `@switch` to resolve that issue.
The broader goal is server-rendered interactivity without requiring a JavaScript-heavy frontend. Lalik points to tools such as htmx and Datastar as ways to build dynamic applications while keeping most application logic on the server. A demonstration application in Dusty combines zt templates with the surrounding web stack.
Zt is not presented as mature software. Lalik said multiple people are already using it but invited issue reports and design feedback, particularly on control-flow syntax. Its significance is therefore architectural rather than a claim of production readiness: Zig’s compile-time facilities can support a higher-level HTML authoring experience while retaining explicit output, type safety and low-level control.
