> ## Documentation Index > Fetch the complete documentation index at: https://docs.apostate.dev/llms.txt > Use this file to discover all available pages before exploring further. # Verify > Check what a launch presents: the composed machine, a local script that reads the page, a worker and the request headers, public test pages, and FingerprintJS Pro. Check a launch in this order. Each step costs more than the one before it and gets closer to what a real detector sees. ## 1. Read the composed machine `--fingerprint-explain` prints the machine a launch presents and exits without opening a window. Pass the same switches the launch uses: ```bash theme={null} apostate run -- --fingerprint=42 --fingerprint-platform=windows --fingerprint-explain ``` ```text theme={null} apostate fingerprint composition chromium 152.0.7977.83 profile schema 3 catalogue v2 (tables e6fb49ebe4d0b28b2e0b7f3d00b086d7c86a12d54d777f31200400cfb7b87766) platform persona windows host platform linux host cores 14 host memory 16818978816 bytes host backend swiftshader (no DRM render node on this host, not probed) seed 42 seed source --fingerprint (pinned by flag, identical on any machine) reproduce with --fingerprint=42 ... ``` Below the header, one row per value names the layer and the evidence it came from. Lines that start with `!` explain a row, and the `limitations` list at the end names what the launch could not apply on this host. [Quickstart](/quickstart) shows the value rows, and [Seeds and identity](/concepts/seeds-and-identity#read-the-seed-lines) explains the seed lines. The explain output comes from the composition. It does not show what a page reads, and it does not know the locale and timezone a package would look up. The next step shows both. ## 2. Read what a page sees [`what_a_page_sees.py`](https://github.com/heretic-tech/apostate/blob/main/examples/python/what_a_page_sees.py) launches a persona and serves it a page from a local HTTP server. The page reads its values, starts a worker that reads them again, fetches the request headers the browser sent, and posts everything back. The script prints the result as JSON. ```bash theme={null} python3 examples/python/what_a_page_sees.py --seed 42 --platform windows \ --locale en-US --timezone America/New_York --headed ``` Without `--locale` and `--timezone`, the package looks them up from your IP address. `--headed` uses the package's Xvfb on a server. Output from a Debian 13 container on an arm64 host, apostate 0.4.3: ```json theme={null} { "navigator": { "userAgent": "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/152.0.0.0 Safari/537.36", "platform": "Win32", "cores": 12, "memory": 8, "languages": [ "en-US", "en" ], "maxTouchPoints": 0, "webdriver": false }, "userAgentData": { "architecture": "arm", "bitness": "64", "brands": [ { "brand": "Chromium", "version": "152" }, { "brand": "Not?A_Brand", "version": "24" }, { "brand": "Google Chrome", "version": "152" } ], "fullVersionList": [ { "brand": "Chromium", "version": "152.0.7977.83" }, { "brand": "Not?A_Brand", "version": "24.0.0.0" }, { "brand": "Google Chrome", "version": "152.0.7977.83" } ], "mobile": false, "model": "", "platform": "Windows", "platformVersion": "19.0.0" }, "intl": { "locale": "en-US", "timeZone": "America/New_York", "date": "12/31/1969, 7:00:00 PM" }, "screen": { "size": [ 1920, 1080 ], "available": [ 1920, 1032 ], "window": [ 1920, 1032 ], "viewport": [ 1920, 889 ], "pixelRatio": 1, "colorDepth": 24 }, "webgl": { "vendor": "Google Inc. (Intel)", "renderer": "ANGLE (Intel, Intel(R) UHD Graphics 770 (0x00004680) Direct3D11 vs_5_0 ps_5_0, D3D11)" }, "webgpu": { "vendor": "intel", "architecture": "gen-12lp", "device": "", "description": "" }, "fonts": { "Segoe UI": true, "Calibri": true, "Helvetica Neue": false, "Menlo": false, "DejaVu Sans": false }, "voices": { "count": 22, "first": [ "Microsoft David - English (United States)", "Microsoft Mark - English (United States)", "Microsoft Zira - English (United States)" ] }, "mediaDevices": [ "audiooutput" ], "audio": { "sampleRate": 48000, "baseLatency": 0.01 }, "worker": { "userAgent": "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/152.0.0.0 Safari/537.36", "platform": "Win32", "uaPlatform": "Windows", "cores": 12, "memory": 8, "languages": [ "en-US", "en" ], "timeZone": "America/New_York", "gpu": "ANGLE (Intel, Intel(R) UHD Graphics 770 (0x00004680) Direct3D11 vs_5_0 ps_5_0, D3D11)" }, "headers": { "accept-language": "en-US,en;q=0.9", "sec-ch-ua": "\"Chromium\";v=\"152\", \"Not?A_Brand\";v=\"24\", \"Google Chrome\";v=\"152\"", "sec-ch-ua-arch": "\"arm\"", "sec-ch-ua-bitness": "\"64\"", "sec-ch-ua-full-version-list": "\"Chromium\";v=\"152.0.7977.83\", \"Not?A_Brand\";v=\"24.0.0.0\", \"Google Chrome\";v=\"152.0.7977.83\"", "sec-ch-ua-mobile": "?0", "sec-ch-ua-model": "\"\"", "sec-ch-ua-platform": "\"Windows\"", "sec-ch-ua-platform-version": "\"19.0.0\"", "sec-ch-ua-wow64": "?0", "user-agent": "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/152.0.0.0 Safari/537.36" } } ``` What to check in the output: * **Page, worker and headers agree.** The User-Agent, platform, cores, memory, languages, timezone and WebGL renderer in `worker` match the page's. The `user-agent` and `accept-language` headers match `navigator`, and `sec-ch-ua-platform` matches `userAgentData.platform`. * **Locale and timezone match the exit.** Behind a proxy, `intl` and `accept-language` should belong to the proxy's location. [Locale and timezone](/guides/locale-and-timezone) covers the lookup. * **The persona's fonts are present.** A Windows persona reads `true` for Segoe UI and Calibri and `false` for the macOS and Linux families. `false` for Segoe UI means the Windows fonts are not installed on the host. [Fonts](/guides/fonts) covers installing them. * **`webgpu` is not `null`.** On Linux it is `null` in headless launches and in headed launches as root. [Linux servers](/guides/linux-servers#headless-or-headed) compares the modes, and [Known gaps](/known-gaps#webgpu-in-headless-mode-on-linux) tracks the gap. * **`architecture` is the host's.** It reads `arm` here because the host is arm64, and `x86` in an amd64 container. No real Windows machine pairs `arm` with this GPU, and iphey.com flags the pair. [Hosts](/concepts/hosts#arm-hosts) explains why. * **`available` is smaller than `size`** for a Windows persona, by the taskbar. `viewport` is 889 high here, where a headless launch reads 945. The 0.4.3 package passes `--no-sandbox`, so this headed launch shows Chromium's unsupported-flag bar on its first tab, which takes 56 pixels. From 0.4.4 the package keeps the sandbox on where it runs and leaves the flag out. [Known gaps](/known-gaps#a-bar-on-the-first-tab) has the workaround. The script checks five font families by comparing text widths. `document.fonts.check()` returns `true` for every family name, installed or not, so it cannot tell. ## 3. Open public test pages Public test pages read more values than the script, and some compare them with what real browsers report. Open them in a launch with the same persona, proxy and options you use for real work, because several of them also judge the IP address. | Page | What it shows | | ----------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | [BrowserLeaks](https://browserleaks.com) | One page per surface: IP address, JavaScript and navigator values, WebRTC, canvas, WebGL, fonts, Client Hints and the TLS fingerprint. | | [CreepJS](https://abrahamjuliot.github.io/creepjs/) | Values from the page and from workers side by side, with the ones that disagree marked as lies, and scores for how headless or stealth-patched the browser looks. | | [bot.sannysoft.com](https://bot.sannysoft.com) | Automation checks: `navigator.webdriver`, the `chrome` object, permissions, plugins, WebGL vendor and renderer, and older headless tests. | | [FingerprintJS demo](https://fingerprintjs.github.io/fingerprintjs/) | The visitor ID of the open-source FingerprintJS library and every component it hashes. | | [FingerprintJS Pro playground](https://demo.fingerprint.com/playground) | The commercial service's verdicts for the visit, such as bot, VPN, proxy, tampering, anti-detect browser, developer tools and virtual machine, and a suspect score. | | [AmIUnique](https://amiunique.org/fingerprint) | Each attribute next to how often its value occurs in the site's collection of fingerprints. | | [Cover Your Tracks](https://coveryourtracks.eff.org) | How identifying the fingerprint is among the site's visitors, and whether the browser blocks trackers. | [WebRTC](/guides/webrtc) covers checking for WebRTC leaks. ## 4. Measure FingerprintJS Pro [`scripts/measure-fpjs.py`](https://github.com/heretic-tech/apostate/blob/main/scripts/measure-fpjs.py) launches one persona headed through a proxy, loads the FingerprintJS Pro playground and prints the exit's address, country and timezone, the suspect score and each flag behind it. It runs from a checkout of the repository and needs `curl` and a residential proxy. On a server it uses the package's Xvfb. ```bash theme={null} APOSTATE_PROXY=socks5://user:pass@proxy.example:1080 \ python3 scripts/measure-fpjs.py --platform windows --seed 42 ``` Use a new proxy session for each run, or the service sees a returning visitor. `--platform host` measures the real machine for comparison, `--out FILE` saves the full response, and `APOSTATE_BINARY` points it at a local build. [FingerprintJS](/testing/fingerprintjs) has dated results. ## Next steps The test suite checks what pages read on a real browser, in every context, and opens public detector pages beside control browsers. It writes every result to a file. What the offline and live tiers check, and how to read the outcomes. The offline checks and public detector pages from the newest run on each host.