Choosing between cloud and local speech recognition is one of the most important architectural decisions for any real-time transcription application. Both approaches have matured significantly, but they serve different needs. In this guide, we'll break down the trade-offs so you can make an informed choice.

How Cloud ASR Works

Cloud ASR services like Deepgram, Google Cloud Speech-to-Text, and AWS Transcribe operate by streaming audio to remote servers where powerful GPU clusters process it. The typical flow involves:

  1. Capturing audio from the microphone or system audio
  2. Encoding it (usually as raw PCM or Opus)
  3. Streaming via WebSocket to the provider
  4. Receiving partial and final transcripts back
// WebSocket streaming to Deepgram
const ws = new WebSocket('wss://api.deepgram.com/v1/listen', {
  headers: { Authorization: 'Token YOUR_API_KEY' }
});
ws.on('message', (data) => {
  const result = JSON.parse(data);
  if (result.is_final) {
    console.log('Final:', result.channel.alternatives[0].transcript);
  }
});
// Send audio chunks as they arrive
audioStream.on('data', (chunk) => ws.send(chunk));

How Local ASR Works

Local ASR uses models that run entirely on your machine. The most popular option in 2026 is faster-whisper, a CTranslate2-optimized version of OpenAI's Whisper. It supports GPU acceleration via CUDA and can achieve near-real-time performance on modern hardware.

from faster_whisper import WhisperModel

model = WhisperModel("large-v3", device="cuda", compute_type="float16")
segments, info = model.transcribe("audio_chunk.wav", beam_size=5)
for segment in segments:
    print(f"[{segment.start:.2f}s -> {segment.end:.2f}s] {segment.text}")

Head-to-Head Comparison

FactorCloud ASR (Deepgram)Local ASR (faster-whisper)
Latency200-500ms (network dependent)300-800ms (hardware dependent)
Accuracy (English)95-97%92-96%
Multi-language36+ languages99 languages
PrivacyAudio sent to serversFully local
CostPay per minuteFree (hardware cost)
SetupAPI key onlyModel download + GPU
ReliabilityDepends on internetAlways available
95%+Cloud Accuracy
0msLocal Network Latency
99Whisper Languages

When to Choose Cloud ASR

Cloud ASR is the right choice when you need maximum accuracy with minimal setup, your internet connection is reliable, and you're processing languages where cloud models have been specifically tuned. Deepgram's Nova-2 model, for example, has been trained on massive datasets of conversational speech and handles accents, filler words, and cross-talk exceptionally well.

When to Choose Local ASR

Local ASR shines when privacy is paramount, you're working offline or in environments with unreliable internet, or you need to avoid per-minute costs for high-volume processing. It's also the better choice for organizations with strict data residency requirements.

Important: Local ASR performance varies dramatically with hardware. On a MacBook with an M2 chip, faster-whisper's medium model processes audio at roughly 3x real-time. On a machine without a capable GPU, it may be too slow for real-time use.

The Hybrid Approach

Voxclar solves this dilemma by supporting both cloud and local ASR. Users can start with Deepgram for the best accuracy and switch to local processing whenever privacy or connectivity is a concern. This flexibility means you're never locked into a single approach.

"We tested both modes extensively. Cloud ASR gave us 3% better accuracy on average, but local mode eliminated the occasional hiccup we saw with WebSocket connections." — Voxclar Engineering Team

For most interview scenarios, we recommend starting with cloud ASR for its superior accuracy and switching to local mode only when privacy concerns override the accuracy advantage. Read our technical guide on AI interview assistants for a deeper dive into the full pipeline.