whisper.cpp vs WhisperX
A side-by-side comparison of two self-hosted self-hosted ai options — licensing, setup difficulty, resource needs, and what each one replaces.
| Feature | whisper.cpp | WhisperX |
|---|---|---|
| Deploy effort | Read-the-docs project | Read-the-docs project |
| Health score | 100 · Excellent | 96 · Excellent |
| Category | Self-Hosted AI | Self-Hosted AI |
| License | MIT | BSD-3-Clause |
| Language | C++ | Python |
| Setup difficulty | Medium | Medium |
| Min. RAM | 1,024 MB | 4,096 MB |
| Deployment | binary, source | bare-metal, source |
| GitHub stars | ★ 53,894 | ★ 24,211 |
| First released | 2022 | 2023 |
| Replaces | Otter.ai, Google Speech-to-Text | Otter.ai, Rev |
What are whisper.cpp and WhisperX?
whisper.cpp
whisper.cpp is a lightweight, dependency-free C++ implementation of the Whisper automatic speech recognition model. It runs efficiently on CPUs and can serve transcription locally through a built-in HTTP server.
- CPU-efficient transcription
- No external dependencies
- Built-in HTTP server
- Many language models
WhisperX
WhisperX extends Whisper with accurate word-level timestamps and speaker diarization. It uses forced alignment and voice activity detection to produce precise, batched transcriptions.
- Word-level alignment
- Speaker diarization
- Batched inference
- VAD preprocessing
whisper.cpp vs WhisperX: key differences
Whisper.cpp is written in C++, while WhisperX is built with Python. Licensing differs — MIT for whisper.cpp versus BSD-3-Clause for WhisperX. Whisper.cpp is the lighter option, starting around 1,024 MB of RAM against 4,096 MB for WhisperX. Whisper.cpp has the considerably larger community, at 53,894 GitHub stars versus 24,211.
Why pick each one
Choose whisper.cpp if…
- Runs on plain CPUs
- No heavy dependencies
- Quantized models supported
Watch out for
- Command-line focused
- Build from source
Choose WhisperX if…
- Word-level timestamps
- Speaker diarization included
- Fast batched inference
Watch out for
- Diarization needs HF token
- GPU recommended
Frequently asked questions
Is whisper.cpp or WhisperX better?
Neither is universally better. whisper.cpp has the larger community; both share a medium setup difficulty, so the decision comes down to features and licensing.
Are whisper.cpp and WhisperX free and open-source?
Yes. whisper.cpp is licensed under MIT and WhisperX under BSD-3-Clause. Both can be self-hosted at no software cost.
Can I run whisper.cpp and WhisperX with Docker?
whisper.cpp: check the project docs for container support. WhisperX: check the project docs for container support.
Which is lighter on resources, whisper.cpp or WhisperX?
whisper.cpp has the smaller minimum footprint at 1,024 MB of RAM, compared to about 4,096 MB for WhisperX. Real-world usage depends on library size, user count, and enabled features.