# Signals > All 46 components: what each one reads, why it helps and what a value looks like. Source: https://whiskerjs.com/docs/signals/ (last updated 2026-10-26) > **In plain words:** > > A signal (or component) is one measurement, such as the screen size or the list of installed fonts. Each one differs a little between devices; together they tell devices apart. 37 signals rarely change and form the visitorId, sorted into seven groups (graphics, audio, fonts, device, browser, locale, preferences). Nine change too easily (zoom, taskbar, permissions and so on), so they are reported but kept out of the ids. Every component also has its own page, with how the technique works, stability, browser support, privacy and every status it can report: see [Signals](https://whiskerjs.com/signals/) and the [glossary](https://whiskerjs.com/glossary/). WhiskerJS reports 46 components. 37 of them are **stable** and make up the visitorId; each stable component belongs to exactly one of seven groups (the parts of the structuredId). The other 9 are reported for your server to use but kept out of both ids, because they change too easily. How to read each entry: - **Reads**: the browser API and exactly what is taken from it. - **Why it helps**: what makes it differ between devices. - **Typical value**: the shape of an `ok` value. Values shown as “digest” are 32 hex characters (see [How it works](https://whiskerjs.com/docs/how-it-works/#hashing)). - **Support**: where it is usually `ok`, and what it reports elsewhere. Values in the examples are illustrative, not from a particular device. ## Overview | Component | Group | In visitorId | Always hashed | | --- | --- | --- | --- | | [`apple_pay`](https://whiskerjs.com/signals/apple-pay/) | browser | yes | no | | [`audio`](https://whiskerjs.com/signals/audio/) | audio | yes | yes | | [`audio_latency`](https://whiskerjs.com/signals/audio-latency/) | none | no | no | | [`browser_class`](https://whiskerjs.com/signals/browser-class/) | browser | yes | no | | [`canvas`](https://whiskerjs.com/signals/canvas/) | gpu | yes | yes | | [`canvas_readback`](https://whiskerjs.com/signals/canvas-readback/) | none | no | no | | [`color_depth`](https://whiskerjs.com/signals/color-depth/) | device | yes | no | | [`color_gamut`](https://whiskerjs.com/signals/color-gamut/) | prefs | yes | no | | [`content_blockers`](https://whiskerjs.com/signals/content-blockers/) | none | no | no | | [`cpu_architecture`](https://whiskerjs.com/signals/cpu-architecture/) | device | yes | no | | [`device_memory`](https://whiskerjs.com/signals/device-memory/) | device | yes | no | | [`dynamic_range`](https://whiskerjs.com/signals/dynamic-range/) | prefs | yes | no | | [`font_preferences`](https://whiskerjs.com/signals/font-preferences/) | fonts | yes | yes | | [`fonts`](https://whiskerjs.com/signals/fonts/) | fonts | yes | yes (`none` plain) | | [`fonts_canvas`](https://whiskerjs.com/signals/fonts-canvas/) | fonts | yes | yes (`none` plain) | | [`forced_colors`](https://whiskerjs.com/signals/forced-colors/) | prefs | yes | no | | [`hardware_concurrency`](https://whiskerjs.com/signals/hardware-concurrency/) | device | yes | no | | [`heap_limit`](https://whiskerjs.com/signals/heap-limit/) | device | yes | no | | [`intl_locale`](https://whiskerjs.com/signals/intl-locale/) | locale | yes | no | | [`keyboard_layout`](https://whiskerjs.com/signals/keyboard-layout/) | none | no | no | | [`languages`](https://whiskerjs.com/signals/languages/) | locale | yes | no | | [`math`](https://whiskerjs.com/signals/math/) | browser | yes | yes | | [`media_codecs`](https://whiskerjs.com/signals/media-codecs/) | browser | yes | yes | | [`pdf_viewer`](https://whiskerjs.com/signals/pdf-viewer/) | browser | yes | no | | [`permissions`](https://whiskerjs.com/signals/permissions/) | none | no | yes | | [`pixel_ratio`](https://whiskerjs.com/signals/pixel-ratio/) | none | no | no | | [`platform`](https://whiskerjs.com/signals/platform/) | browser | yes | no | | [`plugins`](https://whiskerjs.com/signals/plugins/) | browser | yes | yes (`none` plain) | | [`prefers_contrast`](https://whiskerjs.com/signals/prefers-contrast/) | prefs | yes | no | | [`private_click`](https://whiskerjs.com/signals/private-click/) | browser | yes | no | | [`reduced_motion`](https://whiskerjs.com/signals/reduced-motion/) | prefs | yes | no | | [`screen_frame`](https://whiskerjs.com/signals/screen-frame/) | none | no | no | | [`screen_resolution`](https://whiskerjs.com/signals/screen-resolution/) | device | yes | no | | [`speech_voices`](https://whiskerjs.com/signals/speech-voices/) | none | no | yes (`none` plain) | | [`storage`](https://whiskerjs.com/signals/storage/) | browser | yes | no | | [`time_zone`](https://whiskerjs.com/signals/time-zone/) | locale | yes | no | | [`touch_support`](https://whiskerjs.com/signals/touch-support/) | device | yes | no | | [`ua_client_hints`](https://whiskerjs.com/signals/ua-client-hints/) | browser | yes | no | | [`ua_versions`](https://whiskerjs.com/signals/ua-versions/) | none | no | no | | [`vendor`](https://whiskerjs.com/signals/vendor/) | browser | yes | no | | [`vendor_flavors`](https://whiskerjs.com/signals/vendor-flavors/) | browser | yes | no | | [`webgl_image`](https://whiskerjs.com/signals/webgl-image/) | gpu | yes | yes | | [`webgl_params`](https://whiskerjs.com/signals/webgl-params/) | gpu | yes | yes | | [`webgl_renderer`](https://whiskerjs.com/signals/webgl-renderer/) | gpu | yes | no | | [`webgl_vendor`](https://whiskerjs.com/signals/webgl-vendor/) | gpu | yes | no | | [`webgpu`](https://whiskerjs.com/signals/webgpu/) | gpu | yes | yes | “No” in the last column still means: hashed when the value is longer than 128 characters or not printable ASCII. The exclusion table removes some of these under Brave and Firefox resistFingerprinting; see [How it works](https://whiskerjs.com/docs/how-it-works/#the-exclusion-table). ## gpu: graphics Graphics output depends on the GPU, its driver, the operating system and the browser’s rendering engine together, which makes this the most distinguishing group and also the one that changes after a driver update. ### `canvas` - **Reads**: a 260x80 2D canvas scene (a filled rectangle, the text “Whiskers twitch, jumpy fox” with a cat emoji in Times New Roman and Arial, three circles with `multiply` blending, an even-odd ring), exported with `toDataURL()`. Rendered twice. - **Why it helps**: font rasterising, anti-aliasing, emoji images and blending differ between systems. - **Typical value**: digest. - **Support**: all browsers. `noisy` / `render_mismatch` where readback is randomised; `excluded` under Brave and Firefox resistFingerprinting. ### `webgl_image` - **Reads**: a 32x32 WebGL drawing of one triangle with a procedural colour shader, read back with `readPixels()`. Drawn twice. - **Why it helps**: shader maths and rasterising differ between GPUs and drivers. - **Typical value**: digest. - **Support**: where WebGL 1 is available. `unavailable` / `no_context` without WebGL; `noisy` when readback is randomised; `excluded` under Brave and Firefox resistFingerprinting. ### `webgl_params` - **Reads**: 21 WebGL parameters (texture sizes, viewport limits, bit depths, shading language version and others), the range and precision of four float and int formats in both shader types, and the sorted list of supported extensions. - **Why it helps**: limits and extensions follow the GPU, driver and browser. - **Typical value**: digest. - **Support**: where WebGL 1 is available. ### `webgl_renderer` - **Reads**: the unmasked renderer string from `WEBGL_debug_renderer_info` where the extension exists, otherwise `gl.RENDERER`. In Firefox the extension is not requested (it prints a deprecation warning there) and `gl.RENDERER` already carries the unmasked string. - **Why it helps**: names the GPU, often with the graphics back end. - **Typical value**: `ANGLE (Apple, ANGLE Metal Renderer: Apple M2, Unspecified Version)`; hashed when longer than 128 characters. - **Support**: where WebGL 1 is available. `excluded` under Firefox resistFingerprinting. A software renderer here also sets the `software_renderer` flag. ### `webgl_vendor` - **Reads**: the unmasked vendor string, same method as `webgl_renderer`. - **Typical value**: `Google Inc. (Apple)`. - **Support**: as `webgl_renderer`. ### `webgpu` - **Reads**: `navigator.gpu.requestAdapter()`, then the adapter’s `info` (vendor, architecture, device, description), its sorted feature list and seven limits (`maxBindGroups`, `maxBufferSize`, `maxComputeInvocationsPerWorkgroup`, `maxComputeWorkgroupStorageSize`, `maxStorageBufferBindingSize`, `maxTextureDimension2D`, `maxVertexBuffers`). No device is requested, and the deprecated `requestAdapterInfo()` (which warns in the console) is not called. - **Why it helps**: a second, newer view of the GPU. - **Typical value**: digest. - **Support**: browsers with WebGPU, in secure contexts. `unavailable` / `no_api` without `navigator.gpu`, `no_context` when no adapter is returned. ## audio ### `audio` - **Reads**: an `OfflineAudioContext` (1 channel, 5000 frames at 44100 Hz) renders a 10 kHz triangle wave through a dynamics compressor; the last 500 samples are taken. Nothing is played and no audio device is opened. - **Why it helps**: the floating-point details of the audio stack differ between engines, operating systems and CPUs. - **Typical value**: digest. - **Support**: all current browsers. `blocked` / `silent` when the render is all zeros; `excluded` under Brave. ## fonts Which fonts are installed, and how the default fonts are set, depend on the operating system, its language packs and installed software. ### `fonts` - **Reads**: for each of 54 font families, text in that font with a generic fallback (`monospace`, `sans-serif`, `serif`) is measured in hidden spans and compared with the fallback alone. A family counts as present when any width or height differs. The spans sit in one hidden, off-screen container that is removed at once. - **Why it helps**: installed fonts vary a lot between systems. - **Typical value**: digest of the sorted list of found families, or `none`. - **Support**: needs a `document.body` and layout (`unavailable` / `no_document` or `no_layout` otherwise). `excluded` under Brave. ### `fonts_canvas` - **Reads**: the same 54 families, detected a second way: canvas `measureText()` widths at 72 px against the three fallbacks. No DOM layout, so page CSS cannot disturb it. - **Typical value**: digest, or `none`. - **Support**: all browsers with a 2D canvas. `excluded` under Brave. ### `font_preferences` - **Reads**: the width of the text “Whiskers quietly judge 0123456789” in seven hidden spans: the browser default font, `serif`, `sans-serif`, `monospace`, `system-ui`, `-apple-system`, and the default font at 1 px (which reveals the minimum font size setting). - **Why it helps**: follows the user’s font settings and the operating system’s system font. - **Typical value**: digest. - **Support**: needs a body and layout. ## device: screen, memory and CPU ### `screen_resolution` - **Reads**: `screen.width` and `screen.height`, larger side first, so that rotating a phone does not change it. - **Typical value**: `1920x1080`, `2560x1440`, `932x430`. - **Support**: all browsers. `excluded` under Firefox resistFingerprinting. ### `color_depth` - **Reads**: `screen.colorDepth`. - **Typical value**: `24`, `30`. ### `hardware_concurrency` - **Reads**: `navigator.hardwareConcurrency` (logical CPU threads). - **Typical value**: `8`, `12`. - **Support**: all current browsers. Some browsers cap or round it. `excluded` under Brave and Firefox resistFingerprinting. ### `device_memory` - **Reads**: `navigator.deviceMemory` (approximate GB, coarse buckets). - **Typical value**: `8`, `4`. - **Support**: Chromium-based browsers only. Safari, iOS browsers and Firefox do not offer it, so it is `unavailable` / `no_api` there by design. ### `heap_limit` - **Reads**: `performance.memory.jsHeapSizeLimit`. - **Typical value**: `4294705152`. - **Support**: Chromium-based browsers only; `unavailable` elsewhere. ### `cpu_architecture` - **Reads**: computes `Infinity - Infinity` in a `Float32Array` and reports the high byte of the resulting NaN’s bit pattern. - **Why it helps**: x86 produces a NaN with the sign bit set, ARM one without, so it tells CPU families apart even when the user agent hides them. - **Typical value**: `255` (x86), `127` (ARM). ### `touch_support` - **Reads**: `navigator.maxTouchPoints`, whether `document.createEvent('TouchEvent')` works, and whether `ontouchstart` exists on the window. - **Typical value**: `points=0,event=0,start=0` (desktop), `points=5,event=1,start=1` (phone). ## browser: engine and build ### `browser_class` - **Reads**: WhiskerJS’s own class: `brave`, `firefox_rfp`, `firefox`, `safari`, `chromium` or `other`, from `navigator.brave`, the user agent, `navigator.vendor` and the resistFingerprinting traits. - **Why it helps**: picks the exclusion row; separates browser families. - **Typical value**: `chromium`. ### `math` - **Reads**: 24 Math results (acos, acosh, asin, asinh, atanh, atan, sin, sinh, cos, cosh, tan, tanh, exp, expm1, log1p and polyfill forms of some, plus `PI` to the power -100) on fixed inputs. The operations and inputs are adapted from FingerprintJS 5.3.0 (MIT). - **Why it helps**: the last digits of these functions differ between JavaScript engines and their versions. - **Typical value**: digest. ### `media_codecs` - **Reads**: for 8 audio and 12 video MIME types, `canPlayType()` on a new `