PocketSphinx

by CMU Sphinx

Lightweight CMU Sphinx engine for embedded keyword spotting.

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TL;DR

Best for wake-word / command-grammar systems on microcontrollers. Pricing: free.

Category
Open source
License
NOASSERTION
Stars
★ 4.3k
Last push
2026-08-03
Pricing
free
Platforms
Linux, macOS, Windows, Android, iOS

What it is

The embedded variant of CMU Sphinx. BSD-2-Clause.

Best for: Wake-word / command-grammar systems on microcontrollers.
Watch out for: WER far behind modern models; small acoustic models only.

Install / use

pip install pocketsphinx

Features

Speaker diarizationNo
Word-level timestampsYes
Streaming / real-timeYes
Languages supported20
HIPAA eligibleNo

Links

GitHub repo ↗

PocketSphinx vs Whipscribe

FeaturePocketSphinxWhipscribe
CategoryOpen sourceTranscription APIs
Pricingfree$4–$24 one-time packs (credits never expire) · $2 single unlock · 60 min free on signup
Speaker diarizationNoYes
Word timestampsYesYes
StreamingYesNo
Languages2099
PlatformsLinux, macOS, Windows, Android, iOSWeb, API, MCP

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