Build & Feature Flags

bext-server uses Cargo feature flags to keep the binary lean. Enable only what your deployment needs.

Available Features

Feature	What it enables	When you need it
`v8`	V8 SSR engine (heap snapshots, TurboFan JIT)	Default. The only supported render engine — required for SSR.
`tls`	Auto-TLS (Let's Encrypt / ZeroSSL), SNI, OCSP	Any production server serving HTTPS.
`nginx-compat`	Drop-in nginx.conf parser, masquerade mode	Replacing nginx. Required for `--nginx-masquerade`.
`php`	PHP/FastCGI (embedded SAPI + FPM proxy)	WordPress, Laravel, or any PHP site.
`redis`	Redis pub/sub, sessions, distributed cache	Horizontal scaling across multiple instances.
`realtime`	SSE + WebSocket hub, topic pub/sub	Real-time features (chat, notifications).
`waf`	Web Application Firewall	IP filtering, geo-blocking, SQLi/XSS detection.
`plugins`	WASM + QuickJS + nsjail sandbox	Running third-party plugins.
`websocket-proxy`	Upstream WebSocket proxy passthrough	Proxying WebSocket connections to backends.
`otel`	OpenTelemetry tracing + metrics	Observability pipelines (Jaeger, Grafana).
`h3-quic`	HTTP/3 over QUIC	Bleeding-edge HTTP/3 support.
`ebpf`	eBPF-based monitoring	Kernel-level observability.
`react-compiler`	React Compiler Rust (auto-memoization)	Experimental. Optimizes React bundles at build time.
`turbopack`	In-process Turbopack bundler	Experimental. Requires nightly Rust.
`route-css`	Rust-native Tailwind CSS generation	Per-route CSS, `bext css` command, live rebuild.

Common Build Profiles

Development (single app)

cargo build -p bext-server --release

Uses default features (v8 + route-css). Good for local development and simple deployments.

Production nginx replacement

cargo build -p bext-server --release \
  --features nginx-compat,tls,php

The minimum for replacing nginx on a server with PHP sites.

Production with V8

cargo build -p bext-server --release \
  --no-default-features \
  --features nginx-compat,tls,php,v8

V8 is the only SSR engine. --no-default-features drops feature baggage we don't need for this profile.

Full-featured production

cargo build -p bext-server --release \
  --no-default-features \
  --features nginx-compat,tls,redis,realtime,waf,v8,react-compiler,turbopack,php

Everything enabled. Requires nightly Rust for the turbopack feature:

cargo +nightly-2026-04-02 build -p bext-server --release \
  --no-default-features \
  --features nginx-compat,tls,redis,realtime,waf,v8,react-compiler,turbopack,php,route-css

Bun Detection

bext auto-detects the Bun binary for on-demand compilation. Detection order:

1. BUN_PATH environment variable 2. which bun (searches PATH) 3. /usr/local/bin/bun, /usr/bin/bun 4. $HOME/.bun/bin/bun

Override with: export BUN_PATH=/path/to/bun

Verifying Features

Check which features are compiled into a binary:

bext-server version

Output:

bext 0.1.2
build: release
features: v8, react-compiler, turbopack, tls, redis, realtime, waf, php, nginx-compat

Render Engine

bext ships with V8 as the single SSR engine (via rusty_v8). Characteristics:

	V8
Startup	~1ms per worker (heap snapshots)
JIT	TurboFan
Thread model	tokio-compatible (Send), in-process worker pool
Crash recovery	~1ms snapshot reload + per-route crash markers (see V8 Crash Isolation)
Config	`[render] workers = N` — no engine selection needed

A second backend (WebKit/JavaScriptCore) historically existed; it was removed once V8's snapshot-based cold start made JSC redundant.

Release Profile

The workspace Cargo.toml configures aggressive optimization:

[profile.release]
opt-level = 3
lto = "fat"
codegen-units = 1
strip = true

Build times are ~8-10 minutes with LTO on a typical server. Most of this is the final linking stage.