Safari on macOS

At a glance

• Browser class: safari (the vendor is Apple Computer, Inc.); safari_afp when Advanced Fingerprinting Protection alters canvas or WebGL readback.
• Excluded components: none in stock Safari; 5 under Advanced Fingerprinting Protection (audio, canvas, screen_frame, screen_resolution, webgl_image, ruleId safari_afp).
• CPU threads: a 4 or an 8 is reported as the bucket 4_8.
• Unavailable by design: device_memory, heap_limit, ua_client_hints, ua_versions, keyboard_layout.
• Read only here and on iOS (and, for latency, Android): apple_pay with a version, private_click, audio_latency.
• Lab sample: Mac Safari kept one id across 2 runs at signalsVersion 1.

What works

• Safari-specific components: apple_pay reports version=<n>;can_pay=<1 or 0>, found by asking supportsVersion() from 20 down; can_pay is blocked where canMakePayments() throws (insecure or cross-origin contexts). private_click reads attributionSourceId from a new, unattached <a> element. audio_latency reads AudioContext.baseLatency and closes the context at once.
• Graphics: canvas and WebGL are read as elsewhere. The webgl_renderer string is often generic (for example Apple GPU), which tells less than on other browsers.
• hardware_concurrency: read 16 times; a 4 or an 8 is reported as 4_8, because WebKit alternates between 4 and 8 for scripts on its known-fingerprinting list (Safari 26, Safari Technology Preview 254), also between page loads. Other values are exact.
• Fonts, font preferences, offline audio, Math, codecs, plugins, locale, storage presence and the display preference queries.

What is unavailable or blocked

These report unavailable with ruleId no_api because Safari does not offer the API:

Component	Missing API
device_memory	navigator.deviceMemory
heap_limit	performance.memory
ua_client_hints	navigator.userAgentData
ua_versions	navigator.userAgentData
keyboard_layout	navigator.keyboard

Because a non-ok status counts the same in every run, these do not make the id unstable: they are simply “missing” every time. webgpu depends on the Safari and macOS version; it is unavailable where navigator.gpu is missing.

What WhiskerJS excludes and why

Nothing in stock Safari. The safari row of the exclusion table is empty.

Safari’s Advanced Fingerprinting Protection (AFP) is on in private browsing, and in all browsing where the Safari setting (or a newer Safari’s default) says so. It adds noise to canvas, WebGL and Web Audio readback and reports the window size as the screen. WhiskerJS does not read the setting: it classes a Safari as safari_afp when the canvas or WebGL known-answer probe came back altered. Then:

Component	Why it is left out
audio	Web Audio readback gets noise
canvas	canvas readback gets noise
screen_frame	the window size is reported as the screen
screen_resolution	the window size is reported as the screen
webgl_image	WebGL readback gets noise

All five report excluded with ruleId safari_afp. Stock Safari reads the known answers back exactly and stays safari. Wherever noise is not covered by a row, canvas, webgl_image and audio still catch it: two renders that differ give noisy / render_mismatch, and a failed known-answer probe gives noisy / seeded_noise. canvas_readback then reports altered.

Integrity flags to expect

• iframe_mismatch used to fire in stock Safari and in Playwright’s WebKit build, because WebKit gives a hidden (display: none) iframe a 0 by 0 screen. Since signalsVersion 9 the screen values are compared only when the iframe reports a screen wider than 0, so this no longer happens.
• engine_mismatch checks that a safari or safari_afp class behaves like WebKit: the printed source of eval must be 37 characters and navigator.productSub 20030107. A user-agent switcher can raise it.
• native_tampering and prototype_lie with extensions that change browser functions.
• vm_renderer when macOS runs as a virtual machine guest (Apple Paravirtual device). ua_ch_mismatch is never checked: Safari has no navigator.userAgentData. media_query_mismatch does not run for the safari_afp class.
• Advanced Fingerprinting Protection’s noise is never a flag: it shows in noise_profile and the excluded components.

Early lab observations

An early, small sample at signalsVersion 1, not a benchmark: on a Mac, Safari kept one id across 2 runs, different from the ids of the other three pairs. device_memory was unavailable, by design. The sample used the first collector (30 components), not the current 47.

Testing it yourself

Run the live demo in a normal Safari window and then in a private window, and compare browser_class, noise_profile and the canvas, WebGL and audio statuses. In the private window the class should say safari_afp and five components excluded, which is why the visitorId differs between the two modes. The lab mode copies one line per run. Nothing is sent anywhere.

Support table for Safari on macOS

Expected status of every component in this browser at signalsVersion 9, from the support matrix (updated 2026-10-26). Basis "code" means expected from the library code and documentation, not yet measured; "lab" means seen in the early lab sample.

Component	Status	Basis	Note
apple_pay	ok	code	version=<n>;can_pay=<1, 0 or blocked>; can_pay is blocked in insecure or cross-origin contexts.
audio	varies	code	Excluded (safari_afp) when Advanced Fingerprinting Protection is on: always in private browsing, and in all browsing where the setting says so. Otherwise ok.
audio_latency	ok	code	Read for browser class safari; the context is closed at once.
browser_class	ok	code	Class safari; safari_afp when Advanced Fingerprinting Protection alters canvas or WebGL readback.
canvas	varies	code	Excluded (safari_afp) when Advanced Fingerprinting Protection is on: always in private browsing, and in all browsing where the setting says so. Otherwise ok.
canvas_readback	varies	code	exact, or altered with Advanced Fingerprinting Protection (always in private browsing).
color_depth	ok	code
color_gamut	ok	code
content_blockers	ok	code	none, or the bait names a content blocker hid.
cpu_architecture	ok	code
device_memory	unavailable	lab	Seen unavailable on Mac Safari in the lab sample; Safari does not offer navigator.deviceMemory.
dynamic_range	ok	code
font_preferences	ok	code
fonts	ok	code
fonts_canvas	ok	code
forced_colors	ok	code
hardware_concurrency	ok	code	Read 16 times; a 4 or an 8 is reported as the bucket 4_8, because WebKit alternates between them for scripts on its known-fingerprinting list.
heap_limit	unavailable	code	performance.memory is a Chromium API. Reports unavailable / no_api.
intl_locale	ok	code
keyboard_layout	unavailable	code	No navigator.keyboard here: unavailable / no_api.
languages	ok	code
math	ok	code
media_codecs	ok	code
noise_profile	ok	code	exact in a normal window; seeded for the APIs Advanced Fingerprinting Protection randomises.
pdf_viewer	ok	code
permissions	ok	code
pixel_ratio	ok	code
platform	ok	code
plugins	ok	code
prefers_contrast	ok	code
private_click	ok	code	Safari Private Click Measurement exposes attributionSourceId.
reduced_motion	ok	code
screen_frame	varies	code	Excluded (safari_afp) when Advanced Fingerprinting Protection is on: always in private browsing, and in all browsing where the setting says so. Otherwise ok.
screen_resolution	varies	code	Excluded (safari_afp) when Advanced Fingerprinting Protection is on: always in private browsing, and in all browsing where the setting says so. Otherwise ok.
speech_voices	ok	code	Digest of the voice list, or none; some browsers fill the list late.
storage	ok	code
time_zone	ok	code
touch_support	ok	code
ua_client_hints	unavailable	code	navigator.userAgentData (Client Hints) is a Chromium API. Reports unavailable / no_api.
ua_versions	unavailable	code	navigator.userAgentData (Client Hints) is a Chromium API. Reports unavailable / no_api.
vendor	ok	code
vendor_flavors	ok	code
webgl_image	varies	code	Excluded (safari_afp) when Advanced Fingerprinting Protection is on: always in private browsing, and in all browsing where the setting says so. Otherwise ok.
webgl_params	ok	code	Where WebGL 1 is available; unavailable / no_context without it.
webgl_renderer	ok	code	Often a generic string such as Apple GPU.
webgl_vendor	ok	code
webgpu	varies	code	Depends on browser version, operating system and GPU; needs a secure context. unavailable / no_api without navigator.gpu, no_context without an adapter.

Questions and answers

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