stygian-browser

High-performance, anti-detection browser automation library for Rust.

Built on the Chrome DevTools Protocol via chromiumoxide with comprehensive stealth features for bypassing modern anti-bot systems: Cloudflare, DataDome, PerimeterX, Akamai.

---

Features

Feature	Description	Default
stealth	Navigation spoofing, canvas noise, WebGL randomization, CDP protection	✓
tls-config	TLS fingerprint profiling via rustls (requires stealth)	—
mcp	MCP (Model Context Protocol) tools	—
mcp-attach	Attach to an existing browser via CDP WebSocket (browser_attach tool; requires mcp)	—
metrics	Prometheus metrics exporter	—
extract	Structured data extraction via #[derive(Extract)]	—
similarity	Similarity scoring for duplicate detection	—
browserbase	Optional Browserbase-managed acquisition stage integration (requires MCP/runtime opt-in)	—
full	All features enabled	—

---

Installation

[dependencies]
stygian-browser = "*"
tokio = { version = "1", features = ["full"] }

Enable (or disable) stealth features:

[dependencies]
# stealth is the default feature; disable for a minimal build
stygian-browser = { version = "*", default-features = false }

Enable optional Browserbase acquisition integration:

[dependencies]
stygian-browser = { version = "*", features = ["browserbase"] }

When enabled, runner-first acquisition can opt into a Browserbase-managed stage via request flags. Set BROWSERBASE_API_KEY and BROWSERBASE_PROJECT_ID in the runtime environment.

---

Quick Start

use stygian_browser::{BrowserConfig, BrowserPool, WaitUntil};
use std::time::Duration;

#[tokio::main]
async fn main() -> Result<(), Box<dyn std::error::Error>> {
    // Build a config — defaults are headless Chrome with Advanced stealth
    let config = BrowserConfig::default();

    // Launch a warm pool (2 browsers ready immediately)
    let pool = BrowserPool::new(config).await?;

    // Acquire a browser handle (< 100 ms from warm pool)
    let handle = pool.acquire().await?;

    // Open a tab and navigate
    let browser = handle
        .browser()
        .ok_or_else(|| std::io::Error::other("browser handle already released"))?;
    let mut page = browser.new_page().await?;
    page.navigate(
        "https://example.com",
        WaitUntil::Selector("body".to_string()),
        Duration::from_secs(30),
    )
    .await?;

    println!("Title: {}", page.title().await?);

    // Release the browser back to the pool
    handle.release().await;
    Ok(())
}

---

Configuration

BrowserConfig controls every aspect of browser launch, anti-detection, and pooling.

use stygian_browser::{BrowserConfig, StealthLevel};
use stygian_browser::config::PoolConfig;
use stygian_browser::webrtc::{WebRtcConfig, WebRtcPolicy};
use std::time::Duration;

let config = BrowserConfig::builder()
    // Browser basics
    .headless(true)
    .window_size(1920, 1080)
    // Use a specific Chrome binary
    // .chrome_path("/usr/bin/google-chrome".into())
    // Stealth level
    .stealth_level(StealthLevel::Advanced)
    // Proxy (supports http/https/socks5)
    // .proxy("http://user:pass@proxy.example.com:8080".to_string())
    // WebRTC policy
    .webrtc(WebRtcConfig {
        policy: WebRtcPolicy::DisableNonProxied,
        ..Default::default()
    })
    // Pool settings
    .pool(PoolConfig {
        min_size: 2,
        max_size: 10,
        acquire_timeout: Duration::from_secs(5),
        ..Default::default()
    })
    .build();

Environment Variable Overrides

All config values can be overridden at runtime without recompiling:

Variable	Default	Description
STYGIAN_CHROME_PATH	auto-detect	Path to Chrome/Chromium binary
STYGIAN_HEADLESS	true	false for headed mode
STYGIAN_STEALTH_LEVEL	advanced	none, basic, advanced
STYGIAN_POOL_MIN	2	Minimum warm browser count
STYGIAN_POOL_MAX	10	Maximum concurrent browsers
STYGIAN_POOL_ACQUIRE_TIMEOUT_SECS	30	Seconds to wait for pool slot
STYGIAN_CDP_FIX_MODE	addBinding	addBinding, isolatedWorld, enableDisable, none
STYGIAN_PROXY	—	Proxy URL
STYGIAN_DISABLE_SANDBOX	auto-detect	true to pass --no-sandbox (see note below)

---

Stealth Levels

Level	navigator spoof	Canvas noise	WebGL random	CDP protection	Human behavior
None	—	—	—	—	—
Basic	✓	—	—	✓	—
Advanced	✓	✓	✓	✓	✓

Trade-offs:

• None — maximum performance, no evasion. Suitable for sites with no bot detection.
• Basic — hides navigator.webdriver, masks the headless UA, enables CDP protection. Fast; appropriate for most scraping workloads.
• Advanced — full fingerprint injection (canvas noise, WebGL, audio, fonts, hardware concurrency, device memory), human-like mouse/keyboard events. Adds ~10–30 ms overhead per page but passes all major detection suites.

---

Browser Pool

The pool maintains a configurable number of warm browser instances and enforces backpressure when all slots are occupied.

use stygian_browser::{BrowserConfig, BrowserPool};
use stygian_browser::config::PoolConfig;
use std::time::Duration;

# async fn run() -> Result<(), Box<dyn std::error::Error>> {
let config = BrowserConfig::builder()
    .pool(PoolConfig {
        min_size: 2,
        max_size: 8,
        idle_timeout: Duration::from_secs(300),
        acquire_timeout: Duration::from_secs(10),
    })
    .build();

let pool = BrowserPool::new(config).await?;
let stats = pool.stats();
println!("pool: {}/{} browsers, {} active", stats.available, stats.max, stats.active);
# Ok(())
# }

Browsers returned via BrowserHandle::release() go back into the pool automatically. Browsers that fail their health check are discarded and replaced with fresh instances.

---

Anti-Detection Techniques

navigator Spoofing

• Overwrites navigator.webdriver to undefined
• Patches navigator.plugins with a realistic PluginArray
• Sets navigator.languages, navigator.language, navigator.vendor
• Aligns navigator.hardwareConcurrency and navigator.deviceMemory with the chosen device profile

Canvas Fingerprint Noise

Adds sub-pixel noise (<1 px) to HTMLCanvasElement.toDataURL() and CanvasRenderingContext2D.getImageData() — indistinguishable visually but unique per page load.

WebGL Randomisation

Randomises RENDERER and VENDOR WebGL parameter responses to prevent GPU-based fingerprinting while keeping values plausible (real GPU family names are used).

CDP Leak Protection

The Chrome DevTools Protocol itself can expose automation. Three modes are available via CdpFixMode:

Mode	Protection	Compatibility
AddBinding	Wraps calls to hide Runtime.enable side-effects	Best overall
IsolatedWorld	Runs injection in a separate execution context	Moderate
EnableDisable	Toggles enable/disable around each command	Broad

Human-Like Behavior (Advanced only)

MouseSimulator generates Bézier-curve mouse paths with:

• Distance-aware step counts (12 steps for <100 px, up to 120 for >1000 px)
• Perpendicular control-point offsets for natural arc shapes
• Sub-pixel micro-tremor jitter (±0.3 px)
• 10–50 ms inter-event delays

TypingSimulator models:

• Per-key WPM variation (70–130 WPM base)
• Configurable typo-and-correct rate
• Burst/pause rhythm typical of humans

---

Integration with stygian-proxy

To use proxies from a stygian-proxy pool dynamically (at browser launch time):

use stygian_proxy::types::ProxyConfig;
use std::sync::Arc;

#[tokio::main]
async fn main() -> Result<(), Box<dyn std::error::Error>> {
    use stygian_browser::BrowserPool;
    use stygian_proxy::ProxyManager;

    // Create proxy pool
    let manager = Arc::new(
        ProxyManager::with_round_robin(
            Arc::new(MemoryProxyStore::default()),
            ProxyConfig::default()
        )?
    );

    // Create bridge that implements ProxySource
    let bridge = Arc::new(ProxyManagerBridge::new(manager));

    // Pass to browser config
    let config = BrowserConfig::builder()
        .proxy_source(bridge)
        .build();

    // Each browser context will acquire its own proxy via the bridge
    let pool = BrowserPool::new(config).await?;
    let handle = pool.acquire().await?;

    // This browser is now routed through a proxy from the pool
    // On release: proxy success/failure is automatically recorded
    
    handle.release().await;
    Ok(())
}

When a browser is released after use, the proxy's circuit breaker is updated:

• Clean return to idle queue: proxy marked as success ✓
• Browser unhealthy: proxy marked as failure ✗
• Browser crashed: proxy marked as failure ✗

---

use stygian_browser::{BrowserConfig, BrowserPool, WaitUntil};
use stygian_browser::page::ResourceFilter;
use std::time::Duration;

# async fn run() -> stygian_browser::error::Result<()> {
let pool = BrowserPool::new(BrowserConfig::default()).await?;
let handle = pool.acquire().await?;
let browser = handle
    .browser()
    .ok_or_else(|| std::io::Error::other("browser handle already released"))?;
let mut page = browser.new_page().await?;

// Block images/fonts to speed up text-only scraping
page.set_resource_filter(ResourceFilter::block_media()).await?;

page.navigate(
    "https://example.com",
    WaitUntil::Selector("h1".to_string()),
    Duration::from_secs(30),
).await?;

// Evaluate JavaScript
let title: String = page.eval("document.title").await?;
let h1: String = page.eval("document.querySelector('h1')?.textContent ?? ''").await?;

// Full page HTML
let html = page.content().await?;

// Save cookies for session reuse
let cookies = page.save_cookies().await?;

page.close().await?;
handle.release().await;
# Ok(())
# }

---

WebRTC & Proxy

use stygian_browser::{BrowserConfig};
use stygian_browser::webrtc::{WebRtcConfig, WebRtcPolicy, ProxyLocation};

let config = BrowserConfig::builder()
    .proxy("http://proxy.example.com:8080".to_string())
    .webrtc(WebRtcConfig {
        policy: WebRtcPolicy::DisableNonProxied,
        location: Some(ProxyLocation::new_us_east()),
        ..Default::default()
    })
    .build();

WebRtcPolicy::BlockAll is the safest option for anonymous scraping — it prevents any IP addresses from leaking via WebRTC peer connections.

---

MCP Behavior Policy Usage

When compiled with the mcp feature, you can apply structured anti-bot behavior plans at runtime using browser_apply_behavior_json.

Accepted behavior shapes:

• RuntimePolicy object (direct policy payload)
• InvestigationBundle object (uses nested policy)
• Direct override object (for simple headless / stealth_level tuning)

Example: RuntimePolicy payload

{
    "jsonrpc": "2.0",
    "id": 1,
    "method": "tools/call",
    "params": {
        "name": "browser_apply_behavior_json",
        "arguments": {
            "behavior": {
                "execution_mode": "Browser",
                "session_mode": "Sticky",
                "telemetry_level": "Deep",
                "rate_limit_rps": 0.8,
                "max_retries": 4,
                "backoff_base_ms": 1200,
                "enable_warmup": true,
                "enforce_webrtc_proxy_only": true,
                "sticky_session_ttl_secs": 1800,
                "required_stygian_features": ["browser", "stealth"],
                "config_hints": {
                    "proxy_url": "http://127.0.0.1:8080",
                    "viewport_width": "1366",
                    "viewport_height": "768"
                },
                "risk_score": 0.92
            }
        }
    }
}

Example: InvestigationBundle payload

{
    "jsonrpc": "2.0",
    "id": 2,
    "method": "tools/call",
    "params": {
        "name": "browser_apply_behavior_json",
        "arguments": {
            "behavior": {
                "report": {
                    "page_title": "example",
                    "total_requests": 42,
                    "blocked_requests": 4,
                    "status_histogram": {"200": 38, "403": 4},
                    "resource_type_histogram": {"document": 1, "script": 12},
                    "provider_histogram": {"Cloudflare": 4},
                    "top_markers": [],
                    "hosts": [],
                    "suspicious_requests": [],
                    "aggregate": {
                        "provider": "Cloudflare",
                        "confidence": 0.87,
                        "markers": ["turnstile"]
                    }
                },
                "requirements": {
                    "provider": "Cloudflare",
                    "confidence": 0.87,
                    "requirements": [],
                    "recommendation": {
                        "strategy": "StickyProxy",
                        "rationale": "bot challenge observed",
                        "required_stygian_features": ["browser", "stealth"],
                        "config_hints": {"proxy_url": "http://127.0.0.1:8080"}
                    }
                },
                "policy": {
                    "execution_mode": "Browser",
                    "session_mode": "Sticky",
                    "telemetry_level": "Standard",
                    "rate_limit_rps": 1.0,
                    "max_retries": 3,
                    "backoff_base_ms": 800,
                    "enable_warmup": true,
                    "enforce_webrtc_proxy_only": true,
                    "sticky_session_ttl_secs": 1200,
                    "required_stygian_features": ["browser", "stealth"],
                    "config_hints": {"proxy_url": "http://127.0.0.1:8080"},
                    "risk_score": 0.78
                }
            }
        }
    }
}

Bind behavior to an active session by also passing session_id:

{
    "jsonrpc": "2.0",
    "id": 3,
    "method": "tools/call",
    "params": {
        "name": "browser_apply_behavior_json",
        "arguments": {
            "session_id": "01JXYZ...",
            "behavior": {
                "headless": false,
                "stealth_level": "basic",
                "interaction_level": "medium"
            }
        }
    }
}

Response includes:

• adapter_kind (RuntimePolicy, InvestigationBundle, or DirectOverrides)
• adapter_kind (runtime_policy, investigation_bundle, or direct_overrides)
• plan (normalized behavior plan)
• effective_config (resolved browser config view)
• session_updated flag

---

FAQ

Q: Does this work on macOS / Linux / Windows?
A: macOS and Linux are fully supported. Windows is validated in CI on windows-latest, with runtime behavior depending on the chromiumoxide backend.

Q: Which Chrome versions are supported?
A: The library targets Chrome 120+. Older versions may work but stealth scripts are only tested against current release channels.

Q: Can I use it without a display (CI/CD)?
A: Yes — the default config is headless: true. No display server is required.

Q: Does Advanced stealth guarantee Cloudflare bypass?
A: There is no guarantee. Cloudflare Turnstile and Bot Management use both JavaScript signals and TLS/network-layer heuristics. Advanced stealth eliminates all known JavaScript signals, which is necessary but may not be sufficient.

Q: How do I set a custom Chrome path?
A: Set STYGIAN_CHROME_PATH=/path/to/chrome or use BrowserConfig::builder().chrome_path("/path/to/chrome".into()).build().

Q: Why does stats().idle always return 0?
A: idle is a lock-free approximation. The count is not maintained in the hot acquire/release path to avoid contention. Use available and active instead.

Q: Should I set STYGIAN_DISABLE_SANDBOX=true?
A: Only inside a container (Docker, Kubernetes, etc.) where Chromium's renderer sandbox cannot function due to missing user namespaces. This is auto-detected via /.dockerenv and /proc/1/cgroup on Linux — you normally don't need to set it explicitly. Never set this on a bare-metal host without an equivalent isolation boundary; doing so removes a meaningful OS-level security layer.

For highest-security deployments, run each browser session in its own container and let the container runtime provide isolation — the sandbox flag will be set automatically inside the container.

---

Testing

# Pure-logic unit tests (no Chrome required)
cargo test --lib -p stygian-browser

# Integration tests (requires Chrome 120+)
cargo test --all-features -p stygian-browser

# Run only ignored Chrome tests explicitly
cargo test --all-features -p stygian-browser -- --include-ignored

# Measure coverage for logic units
cargo tarpaulin -p stygian-browser --lib --ignore-tests --out Lcov

Coverage notes: All tests that launch a real browser instance are annotated #[ignore = "requires Chrome"] so the suite passes in CI without a Chrome binary. Pure-logic coverage (config, stealth scripts, fingerprint generation, simulator math) is high; overall line coverage is structurally bounded by the CDP requirement.

---

License

Licensed under the GNU Affero General Public License v3.0 (AGPL-3.0-only).