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. |
If you're unsure which features your binary includes, run bext-server version — it prints the full compiled feature list. This is the fastest way to confirm a feature was included without inspecting the build command.
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:
BUN_PATHenvironment variablewhich bun(searchesPATH)/usr/local/bin/bun,/usr/bin/bun$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.
Related#
- V8 Render Engine — configuration for the
v8feature once compiled in - Rust CSS Engine — configuration for the
route-cssfeature - bext.config.toml — runtime configuration that pairs with compile-time features
- Environment Variables — runtime flags that complement build-time choices
- Architecture: Crate Reference — what each crate provides and how features map to it