capiumbrowser 1.0.3

A stealth Chromium built to withstand bot detection — because it's a real browser.

Not a patched config. Not a JavaScript injection. A real Chromium binary whose fingerprints are rewritten at the C++ source level and compiled in. Page scripts that hunt for injected hooks find nothing to catch — the values a site reads are the persona's values, produced by the engine. Drive it with the Playwright API you already know.

_{Say hi to Capzy 🕵️ — the stealth little guy who helps your automation blend in.}

capiumbrowser.com · Documentation · Pricing · Demo · Examples

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pip install capiumbrowser — import capiumbrowser · CLI: python -m capiumbrowser

Using Node.js? The same browser ships as an npm package for Playwright and Puppeteer.

• Source-level C++ stealth — User-Agent & UA-CH, WebGL/GPU, canvas, audio, screen, hardware, fonts, voices, WebRTC, navigator.webdriver, DevTools, pointer, client-rects — all rewritten in the browser's own source, below the JavaScript layer.
• Coherent per-seed identities — one integer seed derives a complete, self-consistent device (OS, GPU, cores, memory, screen, fonts, UA). Same seed ⇒ same machine, on any host, every run.
• humanize=True — ordinary page.click / fill / type become curved, human-timed mouse, keyboard, and scroll. One flag, and interactions look human rather than scripted.
• geoip=True — the binary resolves its own exit IP through your proxy and pins timezone, WebRTC IP, geolocation, and navigator.languages to match. The clock, locale, and IP all tell one story.
• Plain Playwright over CDP — no patched driver, no init-script signature, no Object.defineProperty shim to detect. Update the engine with pip install -U playwright.
• Always the latest binary — one license key fetches the newest checksum-verified build for your platform and reuses it thereafter.
• Free tier — 1 concurrent session. Paid tiers raise the concurrent-session cap. Start free →

from capiumbrowser import launch_context

browser, ctx, page = launch_context(
    seed=200123,                 # a coherent, repeatable device
    proxy="http://user:pass@host:port", geoip=True,   # exit IP + matching tz/geo/WebRTC
    humanize=True,               # human-like clicks/typing/scrolls
    url="https://fingerprint.com/demo/")

page.fill("#email", "alex@example.com")   # humanized automatically
page.click("#submit")
browser.close()                  # also stops the Playwright driver — no leaked processes

The capiumbrowser Python package is open; the Capium browser binary is licensed per concurrent session. There's a free tier with 1 concurrent session — see Licensing.

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Table of contents

• Install · Why Capium · Licensing & tiers
• What a persona reads · Comparison · How it works
• API · Parameters · Personas & seeds · Fingerprint switches
• Human behavior · Proxies & geo · Fonts
• Framework integrations · Deployment · Platforms
• CLI · Troubleshooting · FAQ · Security · License

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Install

pip install capiumbrowser              # the SDK
pip install -U playwright              # the driver — a normal, independently-updatable dependency
python -m playwright install-deps      # OS libraries for Chromium (once, on Linux)

You do not run playwright install chromium — Capium ships its own binary. On first launch the SDK fetches the per-platform build from the license service (authenticated, checksum-verified) and caches it.

Download the browser — just your license key

The browser binary is fetched with only your Capium license key — no separate token, no manual download, no per-platform URL to figure out. Set the key once:

export CAPIUM_LICENSE_KEY=cap_your_key_here
# or put a `KEY=cap_...` line in ~/.capium/license

Then the right build for your OS/arch downloads automatically — either on first launch, or ahead of time with the CLI:

python -m capiumbrowser install     # ...or skip it: the first launch() downloads the binary for you.

That same key both authorizes the download and licenses the browser, and it's passed to the binary through the environment — never on the command line. The download is checksum-verified before anything runs and cached (under ~/.capium), so it's fetched once and reused. Run python -m capiumbrowser (the info check) to see your license, the installed build, and anything still missing.

Migrating from Playwright? It's a one-line change — the returned object is a standard Playwright Browser:

- from playwright.sync_api import sync_playwright
- pw = sync_playwright().start()
- browser = pw.chromium.launch()
+ from capiumbrowser import launch
+ browser = launch(seed=200123)

  page = browser.new_page()
  page.goto("https://example.com")     # the rest of your code is unchanged

⭐ Star the repo to follow along — Capium tracks Chrome closely and ships new builds as detection evolves.

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Why Capium

• Config-level stealth breaks. playwright-stealth, undetected-chromedriver, and friends inject JavaScript or flip flags. Every Chrome update breaks them, and modern anti-bot ML detects the patches themselves — the very act of hiding trips the alarm.
• Capium patches Chromium source. Fingerprints are modified at the C++ level and compiled into the binary. Detection sites see a real browser because it is one — no init script, no toString tampering, no CDP hooks to sniff.
• Coherence is the product. A convincing device isn't one clean signal; it's every signal telling the same story. Capium derives GPU, screen, fonts, UA-CH, timezone, locale, and WebRTC from a single seed + your proxy's geography, so nothing contradicts anything else.
• Same behavior everywhere. Local, Docker, VPS, Lambda — no environment-specific config.
• Works with your stack. Drop-in stealth for Selenium, undetected-chromedriver, browser-use, Crawl4AI, Crawlee, Scrapling, LangChain, and more. See integrations.

Capium doesn't solve CAPTCHAs, and no stealth tool can promise you'll never see one. What a coherent, real-browser fingerprint does is remove the automation tells that commonly trigger challenges — it reduces friction, it doesn't guarantee a challenge-free session. No CAPTCHA-solving services, no built-in proxy rotation: bring your own proxies and use the Playwright API you already know.

Responsible use. Capium is a stealth browser for legitimate automation, testing, QA, and research. It makes no guarantee of evading any particular bot-detection or anti-fraud system, and results vary by site, proxy, and configuration. You are responsible for complying with the terms of service of the sites you access and with all applicable laws.

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Licensing

The browser binary is licensed per concurrent session — each running browser holds one seat, freed the moment it closes. Installing or activating on many machines is free; only live sessions count, across all your machines. The capiumbrowser SDK never holds a seat itself.

Tier	Concurrent sessions	For
Free	1	Trying it, one browser at a time
Solo	5	Solo projects
Team	20	Small teams
Business	200	Production scraping / QA / monitoring
Scale	2,000+	High-volume automation

See capiumbrowser.com/#pricing for current pricing and to create a key.

Get a key

1. Create an account at capiumbrowser.com and create a license (start with the free 1-session tier). Keys look like cap_XXXXXXXXXXXXXXXXXXXXXXXX.

2. Make it available to the SDK any one way (checked in this order):

   export CAPIUM_LICENSE_KEY="cap_xxxxxxxxxxxxxxxxxxxx"
   # optional — defaults to https://license.capzy.ai
   export CAPIUM_LICENSE_SERVER="https://license.capzy.ai"
   

   …or a file at ~/.capium/license (chmod 600) with a KEY=cap_… line, or pass launch(..., license_key="cap_…").

The same key gates the binary download. The key is passed to the browser via the environment, never on the command line (so it can't leak through ps). Check entitlements without spending a session:

python -m capiumbrowser status
# {"plan": "free", "sessions_cap": 1, "live_sessions": 0, "period_end": "...", ...}

Handle license errors with typed exceptions — CapiumSeatLimitError, CapiumExpiredError, CapiumServerDownError, CapiumConfigError (all subclass CapiumLicenseError → CapiumError). Full model: docs.capiumbrowser.com.

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What a persona reads

On a matching-OS host (a Windows persona on Windows, a macOS persona on macOS), a Capium persona reads clean against a modern fingerprinting suite — with the correct GPU, fonts, and voices for the claimed device:

Signal	Stock Playwright Chromium	Capium
navigator.webdriver	true	false (source-level)
FingerprintJS bot detection	detected	not detected
FingerprintJS tampering / anti-detect	—	false
DevTools/CDP console tell (FPJS developer_tools)	detected	false
User-Agent	HeadlessChrome/…	Chrome/152.0.0.0
window.chrome	thin / missing	present, like real Chrome
Google TTS voices	absent	present (matches real Chrome)
JA4 TLS fingerprint	differs from Chrome	matches stock Chrome
WebRTC IP behind a proxy	real IP leaks	pinned to the proxy exit

Honesty matters more than a green screenshot. A GPU-less headless Linux box makes WebGL fall back to SwiftShader, which any modern suite (and stock Chrome) flags as virtual_machine / anti_detect — an artifact of the host, not the browser. Run headed (Xvfb is fine) on a GPU-backed, matching-OS host for the clean verdict. And os_mismatch is a network signal — genuine Chrome trips it behind some proxies/NATs too, so treat it as a routing concern, not a browser one. Full method: Verifying stealth.

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Comparison

	Playwright	playwright-stealth	undetected-chromedriver	Capium
Patch level	none	JS injection	config / flags	C++ (Chromium source)
Survives Chrome updates	n/a	breaks often	breaks often	yes (rebased builds)
navigator.webdriver	true	false	false	false
Coherent per-seed device	no	no	no	yes
Timezone/locale/WebRTC ↔ proxy	manual	manual	manual	auto (geoip=True)
Human input	no	no	no	humanize=True
Playwright API	native	native	no (Selenium)	native

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How it works

1. You install → pip install capiumbrowser. This downloads nothing but the Python package — the ~230 MB binary needs your license key, so it can't be fetched at pip-install time.
2. First launch → the license-gated binary auto-downloads for your platform (checksum-verified) and caches. It's fetched lazily on that first launch() — or eagerly with python -m capiumbrowser install.
3. Every later launch → the cached binary is reused instantly; plain Playwright starts it with your seed.
4. Upgrade → when a newer SDK bumps the target build (CAPIUM_BINARY_VERSION), the next launch notices the cached binary is a different version, removes it, and downloads the new one — no manual reinstall.

The spoofing lives in the compiled binary — not injected via JavaScript, not set via a detectable CDP Emulation call. Identity comes from one seed; proxy, geolocation, timezone, WebRTC, and locale are all aligned to a single coherent story.

Download mechanics. The binary is fetched from the license service with a signed, path-based GET (/download/distro/chromium-v<version>/capiumbrowser-<os>-<arch>.tar.gz): the key travels in the X-Capzy-License header (never the URL) and the request path is HMAC-signed. The response's X-Capzy-SHA256 is verified against the streamed bytes before extraction, so a corrupted or tampered archive is rejected. The filename is version-independent — only the chromium-v<version>/ folder changes. Env overrides: CAPIUM_LICENSE_KEY (or ~/.capium/license), CAPIUM_VERSION (target a specific build), CAPIUM_BINARY (use an exact local binary, skip download), CAPIUM_DOWNLOAD_URL (unsigned direct URL escape hatch), CAPIUM_HOME (where builds cache). A missing platform, an unpublished version (404), a rejected license (401/403), an unreachable server, or a checksum mismatch each raise a distinct, typed Capium* error.

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API

Every entry point has an await-able twin (launch_async, launch_context_async, launch_persistent_context_async).

Function	Returns	Use for
launch(...)	Browser	full control; create your own contexts/pages
launch_context(url=None, humanize=False, ...)	(browser, context, page)	one-liner: open a page, optionally navigate + humanize
launch_persistent_context(user_data_dir, ...)	BrowserContext	persistent cookies/localStorage/login across runs

from capiumbrowser import launch, launch_async, launch_persistent_context

# Full control
browser = launch(seed=200123, platform="windows", headless=False)

# Proxy + coherent geo (HTTP/HTTPS/SOCKS5, inline creds)
browser = launch(seed=200123, proxy="socks5://user:pass@host:port", geoip=True)

# Explicit timezone/locale always win over geoip auto-detection
browser = launch(seed=200123, proxy="http://host:port", geoip=True, timezone="Europe/London")

# Persistent profile — stays logged in, avoids the "always fresh incognito" tell; extensions need this
ctx = launch_persistent_context("~/profiles/acct1", seed=200123, platform="linux",
                                extension_paths=["/path/to/unpacked-extension"])

# Bring your own flags — disable the defaults and build the command line yourself
browser = launch(stealth_args=False, args=["--fingerprint=200123", "--fingerprint-platform=linux"])

import asyncio
from capiumbrowser import launch_async

async def main():
    browser = await launch_async(seed=200123, proxy="http://host:port", geoip=True)
    page = await browser.new_page()
    await page.goto("https://example.com")
    print(await page.evaluate("() => navigator.userAgent"))
    await browser.close()

asyncio.run(main())

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Parameters

Every parameter the SDK accepts. Unless noted, all of these work on launch, launch_context, and launch_persistent_context (and their _async twins) — launch_context and launch_persistent_context forward everything to launch.

Identity & rendering

Parameter	Type	Default	Description
seed	int | None | "off"	None	Persona seed → a complete coherent device. None = fresh random seed each launch. The range selects the OS family (see Personas & seeds). "off"/"false"/"none" = passthrough (host's real values; debugging).
platform	str	"windows"	Spoofed OS: "windows" | "macos" | "linux". Sets --fingerprint-platform and picks the seed range if you didn't.
headless	bool	False	Headed is recommended (reads cleaner). On a server, run headed under Xvfb.
stealth_args	bool	True	Apply the default coherent fingerprint flags. Set False to build the whole command line yourself via args.
args	list[str] | None	None	Extra raw Chrome flags appended verbatim (see Fingerprint switches).

Proxy, geo & locale

Parameter	Type	Default	Description
proxy	str | dict | "env"/True | None	None	HTTP/HTTPS/SOCKS5 URL with inline creds, a {"server","username","password"} dict, "env"/True (reads CAPIUM_PROXY), or None/"none"/"".
geoip	bool | None	None	Geo coherence, resolved inside the binary. None (default) — OFF: no lookup runs, even with a proxy (a proxy alone doesn't trigger it, so proxied launches aren't slowed). True — ON: pins timezone/geo/WebRTC/navigator.languages to the egress (proxy exit, or the host IP if proxyless). False — explicit opt-out. No SDK-side probe.
timezone	str | None	None	IANA tz (e.g. "America/New_York") → --timezone. Overrides geoip.
locale	str | None	None	BCP-47 (e.g. "en-US") → --lang + --accept-lang. Overrides geoip.

Profiles & extensions

Parameter	Type	Default	Description
user_data_dir	str	—	launch_persistent_context only (first positional arg). Directory where cookies/localStorage/cache persist across runs.
extension_paths	list[str] | str | None	None	Unpacked Chrome extension directory(ies). Extensions require a persistent context.

License

Parameter	Type	Default	Description
license_key	str | None	None	cap_… key. Falls back to CAPIUM_LICENSE_KEY env / ~/.capium/license. Passed to the binary via the environment, never argv.
license_server	str | None	None	Override the license server (default https://license.capzy.ai).
license_through_proxy	bool	False	Route license/session calls through --proxy-server instead of direct.
license_preflight	bool	True	Fail fast with a typed CapiumConfigError when no key is configured, before spinning up a browser. Set False for a dev build that runs without enforcement.

launch_context only

Parameter	Type	Default	Description
url	str | None	None	If set, navigate the returned page to it (domcontentloaded, 60 s) as a driven navigation.
humanize	bool	False	Wire page.click/fill/type/hover to human-like input and attach page.human_* helpers. Sync API only (no-op on async).
human_preset	str	"default"	Pace of humanized input: "default" (natural) or "careful" (slower, more deliberate).

Binary & Playwright passthrough

Parameter	Type	Default	Description
binary	str | None	None	Exact path to the capium wrapper — skips discovery/download (same as CAPIUM_BINARY).
**kwargs	—	—	Forwarded to Playwright's chromium.launch (e.g. slow_mo, timeout, env). For launch_persistent_context, forwarded to launch_persistent_context — so viewport, no_viewport, user_agent, color_scheme, permissions, extra_http_headers, etc. work too (persistent defaults to no_viewport=True unless you pass a viewport).

Prefer the friendly parameters (proxy=, geoip=, timezone=, locale=) over raw args= — reach for args only when a convenience parameter doesn't cover the surface. Environment variables that affect every launch are in CLI & environment.

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Personas & seeds

A persona is a complete, self-consistent device deterministically derived from one integer seed. The seed range selects the OS family (or pass platform= and Capium picks the range for you):

OS family	Seed range	platform=
Windows	10000–99999	"windows"
macOS (Apple Silicon)	100000–199999	"macos"
Linux	200000–299999	"linux"

launch(seed=200123)     # a specific, repeatable device
launch(seed=None)       # random seed each launch (still fully coherent)
launch(seed="off")      # PASSTHROUGH — the host's real values (debugging only)

Tip — pin a seed per account. A fresh random seed every visit looks like a new device each time, which is suspicious when you keep hitting the same site from the same IP. A fixed seed reads as a returning visitor. And match the persona to the host OS — a macOS persona is flawless on a Mac and a Windows persona on Windows, because the host's real text-rasterizer and GPU back the claim.

Launch every persona — and persist per account

from capiumbrowser import launch_context, launch_persistent_context

# One coherent device per OS: pick platform + any stable seed
for platform, seed in (("windows", 200111), ("macos", 200222), ("linux", 200333)):
    browser, ctx, page = launch_context(seed=seed, platform=platform, url="https://browserscan.net/")
    browser.close()                       # non-persistent: close the browser

# Persist a logged-in account across runs — give it a profile DIRECTORY (persistent-only;
# launch()/launch_context() are always throwaway). Returns a context; close the context.
ctx = launch_persistent_context("~/capium-profiles/acct-a", seed=210001, platform="windows")
page = ctx.pages[0] if ctx.pages else ctx.new_page()
page.goto("https://example.com")          # cookies/localStorage persist in the profile dir
ctx.close()

# A fleet: each account its own coherent device AND its own profile
for name, seed in {"acct-a": 210001, "acct-b": 210002, "acct-c": 210003}.items():
    ctx = launch_persistent_context(f"~/capium-profiles/{name}", seed=seed, platform="macos")
    ctx.close()

Full runnable version (personas, persistent profiles, a fleet, proxy+geo, full control): examples/profiles.py.

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Fingerprint switches

The SDK sets the essentials from seed/platform. Everything below is available for precise control — pass any through args=[...] (or stealth_args=False to build the whole command line yourself):

launch(seed=200123, args=[
    "--fingerprint-hardware-concurrency=8",
    "--fingerprint-screen-width=2560", "--fingerprint-screen-height=1440",
])

Identity

Switch	What it controls
--fingerprint=<seed>	Master seed → the whole coherent device. off/false/none = passthrough.
--fingerprint-platform=<windows|macos|linux>	Spoofed OS: navigator.platform, UA, UA-CH platform.
--fingerprint-platform-version=<v>	UA-CH platformVersion.
--fingerprint-brand=<name> / --fingerprint-brand-version=<v>	UA-CH brand and version entries.
--fingerprint-hardware-concurrency=<n>	navigator.hardwareConcurrency (CPU cores).
--fingerprint-screen-width=<n> / --fingerprint-screen-height=<n>	screen.width / screen.height.
--fingerprint-device-scale-factor=<f>	devicePixelRatio.
--fingerprint-storage-quota=<GB>	navigator.storage.estimate().quota in gigabytes (also affects incognito-from-quota checks). Auto-set per-seed by the SDK (128–576 GB) so the real host/container disk never leaks — including on Windows, where no wrapper runs.

Rendering & noise

Switch	What it controls
--fingerprint-noise=<true|false>	Deterministic per-seed noise on canvas image data, measureText, and audio. Default off (per-seed noise can read as tampering when the DevTools tell is patched).
--disable-spoofing=<canvas,font,…>	Selectively turn off spoofing for named surfaces (comma-separated).

Fonts & voices

Switch	What it controls
--fingerprint-windows-font-metrics	Measure default text with Windows metrics (requires real Windows fonts — see Fonts). Default on for a Windows persona.
--fingerprint-sapi-voices=<true|false>	Present the Windows SAPI voice list for a Windows persona.

Location, network & content

Switch	What it controls
--timezone=<IANA>	In-browser timezone (e.g. America/New_York).
--fingerprint-location=<lat,lon>	Geolocation API coordinates (permission auto-granted).
--fingerprint-webrtc-ip=<ip|auto>	The IP WebRTC reports (pin to your proxy exit — the SDK does this with geoip).
--fingerprint-allow-3p-cookies	Allow third-party cookies (some SSO / embedded-payment flows need them).
--disable-ads	Built-in ad/tracker blocker with a login/captcha-safe allowlist (default on).

Most of these have friendly SDK equivalents (timezone=, locale=, proxy=, geoip=). The full per-switch matrix lives in the docs.

---

Human behavior

Behavioral anti-bot systems score how you move, not just what you send. Set humanize=True on any synchronous launch and your ordinary Playwright calls are driven the human way automatically:

browser, ctx, page = launch_context(seed=200123, humanize=True, url="https://example.com")
page.click("#login")          # curved, overshoot-and-settle cursor, then a human press
page.fill("#user", "alice")   # focus, clear, per-key typing with realistic timing & the odd slip
page.hover(".menu")           # natural move onto the element

• Cursor follows a Catmull-Rom spline through bowed way-points, briefly overshoots and settles, timed by a bell-shaped (min-jerk) velocity.
• Keystrokes come from a log-normal inter-key distribution with longer gaps at word boundaries, plus occasional adjacent-key slips noticed and corrected with Backspace.
• Scrolling is an inertial flick that decays toward the target.

Two presets tune the pace: "default" (natural) and "careful" (slower). It's pure Playwright input (page.mouse / page.keyboard) — no CDP tricks. Original methods stay reachable as page.raw_click, etc., and helpers are importable: from capiumbrowser.human import humanize, click, type_text, scroll.

Humanized input is a synchronous engine, so humanize=True applies to the sync API. On async pages it's a safe no-op — drive async input yourself.

---

Proxies & geo

No proxy provider and no credentials ship with the package — you supply your own.

launch(seed=200123, proxy="http://user:pass@host:port", geoip=True)
launch(seed=200123, proxy="socks5://user:pass@host:port")   # RFC 1929 auth

proxy= accepts an HTTP/HTTPS or SOCKS5 URL (inline credentials), a {"server","username","password"} dict, "env"/True (reads CAPIUM_PROXY), or None. Credentials are passed inline to the Capium binary — which authenticates natively (SOCKS5 RFC 1929; preemptive HTTP Proxy-Authorization) — and are URL-encoded so special characters can't truncate the proxy string into a real-IP-leaking DIRECT fallback.

Geo coherence is resolved inside the binary at launch (PreBrowserStart), which geolocates the egress IP and pins timezone, geolocation, WebRTC IP, and navigator.languages — so the WebRTC IP equals the site-visible IP and the clock/locale match the egress geography. There's no SDK-side network call. geoip is tri-state:

• geoip=None (default) — OFF. No geo lookup runs, even with a proxy — a proxy alone does not trigger it (the lookup is a blocking egress round-trip we don't pay unless you ask). Timezone/geo stay at the persona/host defaults. Pass geoip=True to opt into proxy-exit coherence.
• geoip=True — ON. Geolocates the egress and pins timezone/geolocation/WebRTC/navigator.languages to it — the proxy exit when --proxy-server is set, else the host's own public IP.
• geoip=False — explicit opt-out. Same effect as None for a lookup, but forwards --geoip=false so the in-binary resolver is unambiguously off.

Explicit timezone= / locale= always win (they're set at launch, so they also cover the HTTP Accept-Language header).

---

Fonts

Font detection is measurement-based — a font only counts as "present" if it genuinely renders with the right metrics. Capium controls what actually resolves, gating each persona to a coherent per-seed set and hiding the host's other fonts.

• Bundled & free (ship anywhere): DejaVu, Liberation, and the metric-identical MS clones Carlito (= Calibri) and Caladea (= Cambria).
• Proprietary (you supply from a licensed source): genuine Apple fonts for a macOS persona on a non-Mac host, and genuine Microsoft fonts for a Windows persona on a non-Windows host.

On a matching-OS host the persona uses the operating system's own fonts and there's nothing to install.

Copying Windows fonts to a Linux host (Windows persona on Linux) — copy the whole font folder from any real Windows machine you own; it covers the required set (Segoe UI, Segoe UI Light, Calibri, Marlett, MS UI Gothic, Franklin Gothic, Consolas, Courier New) and more:

# on the Linux box:
mkdir -p ~/.local/share/fonts/windows
# from the Windows machine (PowerShell):
scp C:\Windows\Fonts\* user@linuxbox:~/.local/share/fonts/windows/
# back on the Linux box:
fc-cache -f

The distro also ships capium-install-fonts.sh, which installs the free baseline (emoji/CJK + the Carlito/Caladea/Liberation substitutes) via apt and then checks for the required Windows set. Once the fonts resolve, the capium wrapper auto-enables --fingerprint-windows-font-metrics — no flag needed.

Copying Windows fonts to a macOS host — install the same .ttf/.ttc files via Font Book, or drop them into ~/Library/Fonts/ (picked up immediately). Calibri/Cambria are the highest-value ones for text metrics.

macOS persona on a non-Mac host — needs genuine Apple fonts (SF Pro, Helvetica Neue, …) from a Mac you own, placed in the same font locations. This is the hardest cross-OS direction — a macOS persona reads cleanest on a real Mac.

Copy proprietary fonts only between machines you hold licenses for. On Linux, CAPIUM_FONTS_DIR adds a custom font directory; CAPIUM_SUPPRESS_FONT_WARNING=1 silences the "missing Windows fonts" hint once you've supplied them. Full per-OS guide: docs.

---

Framework integrations

Capium is a Chromium fork, so any Chromium automation tool works — point it at the binary and add the persona flags. Runnable examples live in examples/integrations/:

Framework	Language	Example
Selenium	Python	selenium.py
undetected-chromedriver	Python	undetected_chromedriver.py
browser-use	Python	browser_use.py
Crawl4AI	Python	crawl4ai.py
Crawlee	Python	crawlee.py
Scrapling	Python	scrapling.py
LangChain	Python	langchain_loader.py
agent-browser	Shell	agent_browser.sh

Two patterns cover them all:

# 1) Framework launches our binary directly (Selenium, undetected-chromedriver, Crawlee)
from capiumbrowser.download import ensure_binary
from capiumbrowser.config import get_default_stealth_args
binary_path = ensure_binary()                               # auto-downloads if needed
stealth_args = get_default_stealth_args(seed=200123, platform="windows")

# 2) Capium launches first, framework connects over CDP (browser-use, Crawl4AI, Scrapling)
from capiumbrowser import launch_async
browser = await launch_async(seed=200123, geoip=True,
                             args=["--remote-debugging-port=9242"])
# point your framework at http://127.0.0.1:9242 — all stealth flags are already set

---

Deployment

Capium runs identically local, in Docker, and on a VPS. For serverless one-shot scrapes there's a complete AWS Lambda container recipe (headed under Xvfb, cold-start-hardened) in examples/integrations/aws_lambda/.

Build your own image from pip — download the binary at build time with a BuildKit secret so the key never lands in a layer:

FROM python:3.12-slim
RUN pip install capiumbrowser playwright && python -m playwright install-deps chromium
RUN --mount=type=secret,id=capium_license \
    CAPIUM_LICENSE_KEY="$(cat /run/secrets/capium_license)" python -m capiumbrowser install
COPY your_script.py /app/
CMD ["python", "/app/your_script.py"]

DOCKER_BUILDKIT=1 docker build --secret id=capium_license,env=CAPIUM_LICENSE_KEY -t my-capium .

On a headless Linux server, run the browser under a virtual display (Xvfb :99 + DISPLAY=:99) so it launches headed, which reads cleaner than headless.

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Platforms

Platform	Distro tag	Notes
Windows x86_64	windows-x64	Native GPU/fonts back a Windows persona flawlessly
macOS arm64 (Apple Silicon)	macos-arm64	M1–M4 by design (covers 2020+ Macs); a Windows persona uses installed Windows fonts for fallback
Linux x86_64	linux-x64	Defaults to a Windows persona; supply Windows fonts for the cleanest result
Linux arm64	linux-arm64	Same as Linux x64 for aarch64 hosts

The SDK auto-detects your host and downloads the matching tag; macOS Intel and Windows ARM are not published and raise a clear error. Capium currently targets Chromium 152.

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CLI & environment

python -m capiumbrowser info       # environment check: license + binary + deps + system libs
python -m capiumbrowser status     # license entitlements (plan, seats, live sessions, renewal)
python -m capiumbrowser version    # SDK version + the Chromium build it targets
python -m capiumbrowser install    # download the capium browser binary
SEED=200123 PLATFORM=linux PROXY="http://user:pass@host:port" GEOIP=1 HUMANIZE=1 \
  python -m capiumbrowser run https://example.com    # launch a demo browser (Ctrl-C to exit)

info is the "what do I still need installed?" check — Playwright, the binary (path + version), the license key, and (on Linux) required system libraries; it prints a fix for anything missing and exits non-zero if the environment isn't ready. A bare python -m capiumbrowser runs info.

Variable	Purpose
CAPIUM_LICENSE_KEY / CAPIUM_LICENSE_SERVER	license key (cap_…) + server (default https://license.capzy.ai)
CAPIUM_BINARY	exact path to the capium wrapper (skips download)
CAPIUM_DOWNLOAD_URL	direct archive URL ({platform}/{version} placeholders); unsigned escape hatch
CAPIUM_HOME / CAPIUM_VERSION	where distros extract / pin a binary version
CAPIUM_PROXY	default proxy URL used when proxy="env"
CAPIUM_FONTS_DIR / CAPIUM_SUPPRESS_FONT_WARNING	custom font dir / silence the font hint
CAPIUM_DRIVER=patchright	opt into the Patchright driver (default is plain Playwright)

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Troubleshooting

Symptom	Fix
capium wrapper not found	Set CAPIUM_LICENSE_KEY (to download), or CAPIUM_BINARY, or drop the distro beside the package.
no license configured	Set CAPIUM_LICENSE_KEY, pass license_key=…, or create ~/.capium/license (KEY=cap_…).
CapiumSeatLimitError	Free tier is 1 concurrent session — close the other Capium browser (or upgrade the tier).
Still blocked on aggressive sites	Run headed (headless=False under Xvfb) + a residential proxy + geoip=True + humanize=True. Most blocks are IP reputation or a mismatched clock, not fingerprint.
FPJS tampering: true	Cross-OS persona on a mismatched host, or per-seed noise unmasked — run on a matching-OS host; --fingerprint-noise=false is the default.
"Windows persona but missing fonts"	Supply real C:\Windows\Fonts\*.ttf (see fonts) or set CAPIUM_SUPPRESS_FONT_WARNING=1.
os_mismatch: true	A network/transport signal (genuine Chrome shows it too behind some proxies) — a routing concern, not the browser.
Headed browser won't start on a server	Run under Xvfb and export DISPLAY=:99.

More: docs.capiumbrowser.com.

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FAQ

Is this legal? Capium is a browser built on open-source Chromium. Use it only where you're authorized to. Automating systems without authorization, credential stuffing, and account-creation abuse are prohibited.

Is it free? The capiumbrowser Python package is open. The binary has a free tier with 1 concurrent session using the same latest build; paid tiers raise the concurrent-session cap. See capiumbrowser.com.

Do I need a license key? Yes — the binary is license-gated and fails closed. A free key (from the dashboard) gives one concurrent session; a paid key raises the limit.

How is this different from JS stealth plugins? They inject JavaScript that modern ML detects. Capium rewrites fingerprints in the Chromium source and compiles them in — there's no injected hook to catch.

Will detection eventually catch this? Bot detection is an arms race. Source-level patches are much harder to detect than config-level ones, and Capium rebases onto new Chromium and ships updates as detection evolves.

Can I use my own proxy? Yes — HTTP/HTTPS and SOCKS5 are supported natively. Bring your own.

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Security

The SDK fetches the binary over an authenticated request — the license key travels in a header (over TLS), never in the URL, and the request target is HMAC-signed. The response's X-Capium-SHA256 is verified against the downloaded bytes before anything is extracted, so a corrupted or tampered download is rejected. The key is handed to the browser subprocess through the environment, never on argv.

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License

• capiumbrowser Python package (this directory) — open; see LICENSE.
• Capium browser binary (compiled Chromium) — licensed per concurrent session; requires an active key to download and run. Free tier available. See capiumbrowser.com.

_{Capium Browser is a product of Capzy. Use responsibly and only where you are authorized to.}