Which browsers run the transcriber.
Two things decide it: how the browser decodes audio and where the model runs. What we tested, what should work, and what your browser reports.
Runs in your browser, sends nothing. It is the same check the transcriber does before downloading anything.
| Browser | Desktop | Mobile | WebGPU | CPU fallback | Tested by us | Notes |
|---|---|---|---|---|---|---|
| Chrome | Yes | Yes, phone mode | Since 113 on Windows, macOS and ChromeOS; Linux only on Intel Gen12+ (144) or behind a flag | Yes | Chrome 153 on Windows 11, and Chrome on an iPhone 17, 25 September 2026 (log below) | The path we develop and test on. On iPhone, Chrome uses the Safari engine and runs in phone mode (the small model on the processor); verified on an iPhone 17. Chrome for Android (WebGPU since 121) is untested; it would run in phone mode on devices reporting 4 GB or less. |
| Edge | Yes | Untested | Same engine and versions as Chrome | Yes | Not run separately; same engine as Chrome | Expected to behave exactly like Chrome. Listed as tested on that basis only. |
| Firefox | Untested | No | Since 141 on Windows; 145 on macOS Apple silicon; not on Intel Macs or Linux | Yes | Not yet | Firefox 130 and later ship WebCodecs audio decoding, so Firefox 141+ on Windows should take the full-speed path. Older Firefox falls back to CPU mode with whole-file decoding. Firefox for Android has neither WebGPU nor WebCodecs audio. |
| Safari | Untested | Yes, phone mode | Since Safari 26 on macOS and iOS | Yes | iPhone 17, Safari and Chrome (same engine), 25 September 2026: works in phone mode | On iPhone the tool runs in phone mode, the tiny model on the processor, because the graphics path crashed the tab. Verified working by the site owner; timing not yet recorded. Desktop Safari 26 ships WebGPU and WebCodecs audio and should take the full-speed path, untested. Safari 16.4 to 18 fall back to CPU mode with whole-file decoding. |
| Other Chromium browsers (Brave, Opera, Vivaldi, Arc) | Untested | Untested | Follows the Chromium version they are built on | Yes | Not yet | Brave disables WebGPU by default in some configurations; the page reports what it finds. |
"Yes" means we ran the tool there. "Yes, phone mode" means it ran there with the small model on the processor, which is what phones get. "Untested" means the browser ships the needed APIs according to its maker, so it should work, but we have not tried it. "No" means the browser lacks something the tool cannot do without. Version facts are from MDN's browser compatibility data, fetched 25 September 2026. If you run it somewhere marked untested, tell us how it went, with the browser version and the hardware.
The two paths
Full speed. WebCodecs decodes the file a few seconds at a time and WebGPU runs the model on your graphics card. Memory stays flat and the text appears as it goes. This is what we test.
Fallback. Without WebGPU, the model runs on your processor through WebAssembly. Because the site sets no cross-origin isolation headers, that path is single-threaded and slower than WebGPU. Without WebCodecs, the whole file is decoded at once with Web Audio instead of streamed, which works for shorter recordings and can run out of memory on very long ones. The page tells you which of these applies before you commit, and the choice is yours.
In our one test so far, on a 2021 laptop processor, the 71-second sample took 46 seconds in this mode including the model download; slower machines can take longer than the recording. That is one machine; more measurements will be added to the log below and to the examples page as they are made.
Why a working adapter matters more than the browser version
A browser can ship WebGPU and still hand back no adapter: virtual machines, remote desktop, old drivers, blocklisted hardware. So the check asks for an adapter instead of trusting the version number.
Phones
On 25 September 2026 an iPhone 17 running Safari and Chrome downloaded the model, then reloaded the page as transcription began, and on the second try showed "a problem repeatedly occurred": Safari's message for a tab that crashed. That is the moment the graphics backend builds the model, so phones and other low-memory devices now use phone mode: the tiny English model (about 120 MB) on the processor, not the graphics card. Slower, but it avoids that path. Verified the same day on the same iPhone 17 in both browsers. Processing time on the phone has not been recorded yet. Android phones are untested; if you try one, tell us the phone, browser and what happened.
To test the other combinations from a phone, add these to the address: ?device=webgpu or ?device=wasm for where the model runs, ?decode=stream or ?decode=webaudio for how the file is read, and ?model=whisper-tiny or ?model=whisper-base. For example /?device=wasm&decode=webaudio. They change nothing about what is uploaded, which is still nothing.
Hardware
Any graphics card with WebGPU support runs the base model. The one machine we have measured so far ran it on integrated Intel graphics, faster than the recording; the details are with the sample on the examples page. Numbers for discrete graphics cards and phones are still to be measured and are marked as such rather than estimated.
Test log
| Date | Browser | OS and hardware | Result |
|---|---|---|---|
| 2026-09-14 | Chrome, desktop | Windows 11, the development machine (hardware listed with the sample on the examples page) | 71 s synthetic sample transcribed on WebGPU in about 50 s including cached model load; no word errors |
| 2026-09-15 | Chrome, desktop | Same machine | 4:45 MP3 transcribed end to end in about 2 minutes with monotonic timestamps, after the streaming fix |
| 2026-09-25 | Chrome 153, desktop | Windows 11, Intel Core i7-11390H, Intel Iris Xe integrated graphics, 16 GB | 71 s MP3 sample on WebGPU in 25 s with the model cached (27 s including the download in a fresh profile); 0 word errors against the reference; full details on the examples page |
| 2026-09-25 | Safari and Chrome on iPhone 17 | iOS, phone mode (tiny model on the processor) | Transcribed a file in both browsers after the graphics path had crashed the tab twice; reported by the site owner, time not recorded |
| 2026-09-25 | Chrome 153, headless, WebGPU and WebCodecs disabled by script | Same machine, CPU mode (single-threaded WebAssembly) with Web Audio decoding | Same 71 s sample in 46 s including the model download; 165 words, same text as the WebGPU run |