Vosk vs NVIDIA NeMo ASR
Both are alternatives to Deepgram. Here's how they stack up — verified facts, no spin.
Also searched as NVIDIA NeMo ASR vs Vosk — same comparison, one verdict.
Vosk and NVIDIA NeMo ASR are closely matched on ownership (95 vs 89) — this one comes down to pricing and to which trade-offs below you can live with.
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.
NVIDIA NeMo ASR
The strongest open streaming and diarization story.
NeMo is NVIDIA's conversational-AI toolkit, and its speech models — the Parakeet and Conformer families — are among the most accurate open options available, with genuine streaming support and a mature diarization pipeline. This is the closest open equivalent to what you are buying from a managed service, including the real-time behaviour that is otherwise the hardest thing to reproduce. Apache-2.0, with the expected trade-off that it is built for NVIDIA hardware and is a heavier framework to adopt.
Side by side
6 points of comparison, every one read from a verified field. Green marks the side that wins a row outright. A dash means we do not hold that fact — never that it is zero.
| Vosk | NVIDIA NeMo ASR | |
|---|---|---|
| Sovereignty ScoreOur transparent 0–100 composite for data ownership and exit cost. | 95 | 89 |
| Open source | Yes | Yes |
| Self-hostable | Yes | Yes |
| Local-first data | Yes | Yes |
| License | Apache-2.0 | Apache-2.0 |
| Pricing | Free, Apache-2.0. | Free and Apache-2.0; assumes NVIDIA GPU hardware. |
Vosk edges it on the Sovereignty Score, but the right pick depends on the trade-offs below.
Weighing both against staying on Deepgram? Is Deepgram free? What it actually costs →
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
NVIDIA NeMo ASR
Strengths
- +Best open streaming performance — the managed services' main advantage
- +Mature speaker diarization built into the toolkit
- +Top-tier accuracy on English benchmarks
- +Apache-2.0 including the model weights
Trade-offs
- −NVIDIA hardware in practice
- −Large framework — heavier to adopt than a single library
- −Fewer languages well covered than Whisper
Which one fits you
The trade-offs above, turned into a decision. Find the line that describes your team.
Choose Vosk
if a lower exit cost matters more to you than any single feature, and real-time on CPU — no GPU required at all.
Choose NVIDIA NeMo ASR
if best open streaming performance — the managed services' main advantage.
Neither, yet
if both carry a real cost you should weigh first — noticeably less accurate than Whisper on hard audio, and nVIDIA hardware in practice. If either of those is a dealbreaker for your team, the shortlist is wrong rather than the choice.
Vosk vs NVIDIA NeMo ASR — common questions
Is Vosk a better fit than NVIDIA NeMo ASR for speech recognition & transcription?
It depends on what you are optimising for, and the honest split is this: Vosk scores 95 to NVIDIA NeMo ASR's 89 on data ownership and exit cost, so it is the safer choice if you care about being able to leave. NVIDIA NeMo ASR earns its place on a different axis — best open streaming performance — the managed services' main advantage. Neither is a wrong answer for every team; the table above is the actual comparison.
What happens if we want to switch later?
Vosk keeps its data local or in open formats, so leaving is an export rather than a negotiation. NVIDIA NeMo ASR is still self-hostable, so the files stay on your server either way — but it is not local-first by design, so check what its export produces before you rely on it.
Can I self-host Vosk or NVIDIA NeMo ASR?
Both can be self-hosted. The difference is what it costs you in time rather than whether it is possible — see the setup and maintenance rows above.
Are Vosk and NVIDIA NeMo ASR both alternatives to Deepgram?
Yes — both appear in our Deepgram comparison, which is why they are worth putting side by side. People usually arrive here already having decided to move off Deepgram and now choosing between the two replacements, which is a narrower and much easier question.
Related alternative guides
Facts verified 2026-08-11. Licenses and pricing change — spotted something out of date? That's a correction we want.