The bext engine

A render & execution engine, written in Rust.

Under every bext site is an engine: it compiles TypeScript and JSX, runs your code in a pool of V8 isolates, renders HTML in under a millisecond, caches and isolates — all in a single binary. That technology is what's licensable and embeddable.

What's inside

Six layers, one binary

Every layer is written from scratch in Rust, built for speed and isolation — with no native dependencies to wire together.

Rust core

An async, GC-free, production server: routing, automatic TLS, compression, ISR. One binary, zero runtime dependencies.

tsc-rs compiler

Our own TypeScript/JSX compiler in Rust — type-stripping + JSX transform. WASM-portable: it runs in the browser too.

V8 isolate pool

Your loaders and components run in shared, supervised V8 isolates — warm, pooled, with a circuit breaker and render budget.

route_css

A Rust Tailwind generator (encre-css) emits exactly the utilities each page uses, at compile time. WASM-portable as well.

Streaming SSR + ISR

Server-first React via PRISM: TTFB streaming, Suspense, incremental static regeneration, cache-key normalization.

Sandbox & security

WAF, rate limiting, per-site isolation, sandboxed execution. Every workload is contained.

Measured in production

Fast where it counts

8.9ms
p50 page render
<1ms
incremental transpile
8isolates
shared V8 pool
2.8MB
compiler in WASM
Portable

The same engine runs anywhere — even in a tab

Because the compiler and CSS engine are pure Rust, we compile them to WebAssembly. play.bext.dev is the proof: it compiles and renders real bext code entirely in the browser, using our actual toolchain. Server, edge, CI, browser, agent sandbox — the same engine, everywhere.

See the engine run in your browser →
Embeddable

Built to drop into your product

The engine is a clean, ownable dependency — not a service to call. Ideal for platforms that need to execute and render generated code, safely and at scale.

Code-gen sandboxes

Compile and run AI-generated code in disposable isolates, with renders measured in milliseconds.

App preview

Give users an instant, live preview of the app an AI just wrote — like our playground.

Agent environments

A contained, fast runtime for agents to build, test, and serve real applications.

Edge & self-host

A single binary to deploy anywhere, or a library to embed — with no external runtime.

Build on it. Or embed it.

Free to run, self-host, and distribute. An OEM license to embed it in your product or AI platform.

Build freeLicense the engine