Is ruyiJS for you?

Headless Chrome and Playwright hand you a whole browser: a GPU-rendering, window-managing, memory-hungry process that anti-bot vendors have spent years learning to detect. ruyiJS takes the opposite path — it embeds only the Firefox internals that matter for automation and leaves the rest behind:

• The real engine, not an impersonation. Genuine SpiderMonkey (Firefox 158) and the Necko network stack execute a site's JavaScript, challenges, signatures, and fingerprints exactly as Firefox would.
• Truly headless. No window, no layout, no renderer. A pure JavaScript + Web API environment that starts fast and stays light.
• Isolated and reproducible. Each Context is its own process with a persistent JavaScript world and its own proxy, so sessions never leak into each other.
• Offline when you need it. Serve scripts and responses yourself and replay a whole captured flow with no network.

If you scrape, reverse-engineer web JavaScript, or collect data behind a challenge, it's for you. If a plain HTTP client already gets your pages, you don't need it.

Runs on Windows x64 with Python 3.10+ (verified on Python 3.14). The wheel bundles the pinned native runtime, so there's nothing else to download.

🚀 Quick start

1 · Install.

python -m pip install ruyijs

_{The wheel ships the SHA256-pinned SpiderMonkey + Necko runtime; local scripts run offline right after install. No browser download.}

2 · Open a context and run JavaScript. Variables and functions persist across eval calls within the same context.

from ruyijs import Context

with Context() as context:
    context.eval("let count = 40")
    print(context.eval("count += 2"))        # 42
    print(context.eval("navigator.userAgent"))

3 · Point it at a real target. Configure the environment, load the page, and let the site's own JavaScript mint whatever token it demands.

with Context(proxy="http://127.0.0.1:7890") as context:
    context.configure_fingerprint({
        "navigator": {"language": "zh-CN", "hardwareConcurrency": 8},
        "locale": {"timezone": "Asia/Shanghai"},
    })
    context.load_page("https://target.example/", html)
    token = context.eval("window.__sign(payload)")   # run the page's signer
    print(token)

🏗️ How it fits together

Python  ──►  ruyiJS Context (isolated process)  ──►  Target site
                 ├─ SpiderMonkey — Firefox 158 JS engine
                 ├─ 38 browser contexts — DOM · Canvas · Workers · iframes · …
                 └─ Necko — HTTP/1.1 · 2 · 3, per-context proxy

Your Python code drives a Context. Inside it, the genuine SpiderMonkey engine runs the page's scripts against a real DOM and 38 bounded browser subsystems, while in-page fetch/XHR ride the Necko transport. The implementation lives under src/ (domain, application, and every browser subsystem) and python/ruyijs/ (the binding).

✨ Features

Run a site's JavaScript

Execute scripts in a persistent context, load real HTML with iframes and classic scripts, and query the resulting DOM. References to live JS objects come back as JSObject / JSFunction you can call from Python.

Capability	How
Execute JS, keep state	context.eval(src) — variables and functions persist
Get a callable back	context.eval(src, to_py=False) → JSFunction
Load a page	context.load_page(url, html) — relative URLs resolve against url
Top-level navigation	context.navigate(url) — no Referer, Sec-Fetch-Site: none
Query the DOM	context.eval("document.querySelector('#x').textContent")

with Context() as context:
    context.set("config", {"offset": 2})
    add = context.eval("(value) => value + config.offset", to_py=False)
    print(add(40))  # 42

Configure the browser environment

Set Navigator, Screen, viewport, timezone, and locale through one validated profile surface. Commit it before the first page script runs.

with Context() as context:
    context.configure_fingerprint({
        "navigator": {"language": "zh-CN", "hardwareConcurrency": 8},
        "screen": {"width": 1920, "height": 1080},
        "viewport": {"width": 1280, "height": 720},
        "locale": {"timezone": "Asia/Shanghai"},
    })
    print(context.eval("[navigator.language, screen.width]"))  # ['zh-CN', 1920]

Native network over Necko

In-page fetch and XHR ride real HTTP/1.1, 2, and 3, through a proxy scoped to the context. Serve responses yourself with put_resource() to replay an entire captured flow offline. Inspect every request with net_log().

with Context(proxy="http://127.0.0.1:7890", timeout=30) as context:
    context.load_page("https://example.com/", "")
    context.eval("globalThis.r = null; fetch('/api').then(x => x.json()).then(v => r = v)")
    context.advance(25)               # drive the event loop until it settles
    print(context.eval("r"))

Python ↔ JavaScript bridge

Pass data in with set(), get callable JS functions out, and expose Python functions to the running script. Workers, Service Workers, and iframes are included.

with Context() as context:
    context.expose(lambda a, b: a + b, "add")
    print(context.eval("add(20, 22)"))  # 42

Deterministic clock

Drive timers with a logical clock for perfectly reproducible runs, or use the system clock for live work. The host advances time explicitly.

with Context() as context:
    context.configure_clock("logical", epoch_ms=1700000000000)
    context.eval("globalThis.result = 0; setTimeout(() => { result = 42 }, 10)")
    context.advance(10)
    print(context.eval("result"))  # 42

Errors and logs

JavaScript exceptions surface as JSError with name, message, and stack. console_log() and net_log() return the captured console and network records.

from ruyijs import Context, JSError

with Context(timeout=10) as context:
    try:
        context.eval("throw new TypeError('bad input')", filename="demo.js")
    except JSError as error:
        print(error.name, error.message)  # TypeError bad input
        print(error.stack)

🛡️ Verification systems it defeats

Each example drives the site's own JavaScript to produce the parameters it demands, then completes the flow end to end. All ship runnable in the package: python -m ruyijs.examples <name>.

System	Category	Example
瑞数 Ruishu 5/6	Dynamic VM / page protection	fangdi · cebwm
极验 Geetest	Slider / one-click	geetest
腾讯天御 Tencent Captcha	No-feel + slider	tianyu
数美 Shumei	Slider	shumei
网易易盾 NetEase Yidun	Smart check	yidun
Arkose Labs + iovation	Enterprise risk / device	expedia-taap
CreepJS	Fingerprint audit — passes every section	creepjs

Full production data-collection flows: BOSS 直聘, 今日头条 Toutiao, 抖音 Douyin, 小红书 RedNote, Google, Expedia TAAP.

🔒 Strictly prohibited for any unlawful use. ruyiJS is provided solely for research into a new generation of AI browsers. Live results depend on current network conditions and each site's present responses.

🧪 Examples

Examples ship inside the package — no need to clone the repo:

python -m ruyijs.examples                      # list every example and its install path
python -m ruyijs.examples google --query python --pages 1
python -m ruyijs.examples boss --query ai --city 101210100
python -m ruyijs.examples fangdi               # 网上房地产 (Ruishu 6)
python -m ruyijs.examples cebwm --pages 3      # 光大理财 (custom Ruishu)
python -m ruyijs.examples toutiao --pages 3    # 今日头条
python -m ruyijs.examples xhs --pages 3        # 小红书 / RedNote home feed
python -m ruyijs.examples geetest              # 极验 one-click
python -m ruyijs.examples yidun                # 网易易盾
python -m ruyijs.examples shumei               # 数美 slider
python -m ruyijs.examples tianyu               # 腾讯天御

Every example supports --direct (direct connection) and --proxy http://127.0.0.1:7890. Add --help after a name for all options, and --output result.json to save results. Each example directory ships its own README.

📚 Documentation & API

Context.eval / set / expose	Execute JS, pass data in, expose Python callbacks
load_page / navigate / put_resource	Load HTML, top-level navigation, serve resources offline
configure_fingerprint / configure_environment	Navigator, Screen, viewport, timezone, locale
configure_clock / advance / tick	Logical vs. system clock, drive the event loop
JSError / console_log / net_log	Errors as exceptions, console and network records
JSObject / JSFunction / get_runtime_path	Live JS handles, bundled-runtime path

📏 Scope & limitations

ruyiJS provides JavaScript execution and a broad Web API environment on Windows x64. It has no browser window and no full page layout or rendering — it is a tool for automation, analysis, and research. Use it in compliance with the terms of service of any site you interact with and with applicable law.

Related: ruyiHttp — a Requests-style Python HTTP library built on Firefox's native networking components.

💬 Contact

Questions, permission requests, commercial licensing, or just to talk shop — add the author on WeChat, or scan to join the discussion group.

WeChat: 如意

Group: AI 浏览器过检测交流群

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📄 License

Licensed under the Mozilla Public License 2.0. See NOTICE for third-party attributions.

📌 As a courtesy: for redistribution and commercial use, please obtain the author's permission — add the author on WeChat (ID: 如意) or open an issue on GitHub.

If ruyiJS saved you from reimplementing a browser, a ⭐ helps others find it.