Vosk vs WhisperX
Both are alternatives to Deepgram. Here's how they stack up — verified facts, no spin.
Also searched as WhisperX vs Vosk — same comparison, one verdict.
Vosk
Real-time transcription on a CPU. Runs on a Raspberry Pi.
Vosk is a lightweight offline speech-recognition toolkit built for constrained environments — it runs in real time on a CPU, works on Android, iOS and single-board computers, and its models are tens of megabytes rather than gigabytes. It will not match Whisper on accuracy for difficult audio. It is the right answer when you need speech recognition on a device, offline, with no GPU and no network, which is a requirement no managed API can satisfy at any price. Apache-2.0.
WhisperX
Accurate word timestamps and speaker labels — Whisper's two weak spots, fixed.
WhisperX wraps Whisper with forced phoneme alignment to produce genuinely accurate word-level timestamps, and adds speaker diarization so output is attributed by speaker. Those are precisely the two things plain Whisper does poorly and the two things a managed API is usually bought for. If your product needs subtitles that land on the word, or meeting transcripts that say who spoke, this closes the gap. BSD-2-Clause, though note the diarization component it uses carries its own model terms worth checking.
Side by side
| Vosk | WhisperX | |
|---|---|---|
| Sovereignty Score | 95 | 90 |
| Open source | Yes | Yes |
| Self-hostable | Yes | Yes |
| Local-first | Yes | Yes |
| License | Apache-2.0 | BSD-2-Clause |
| Pricing | Free, Apache-2.0. | Free. Diarization models may require accepting separate terms. |
Vosk edges it on the Sovereignty Score, but the right pick depends on the trade-offs below.
Vosk
Strengths
- +Real-time on CPU — no GPU required at all
- +Tiny models; runs on phones and single-board computers
- +Fully offline, which some products require by law
- +Around twenty languages supported
Trade-offs
- −Noticeably less accurate than Whisper on hard audio
- −Smaller language coverage
- −No built-in diarization
WhisperX
Strengths
- +Word-level timestamps accurate enough for subtitles
- +Speaker diarization included in the pipeline
- +Batched inference makes it fast on long recordings
- +BSD-2-Clause
Trade-offs
- −Diarization models have their own licence terms to review
- −More moving parts than faster-whisper alone
- −Heavier GPU memory requirement with diarization enabled
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Facts verified 2026-08-11. Licenses and pricing change — spotted something out of date? That's a correction we want.