Speech-to-Text API Comparison 2026: OpenAI vs Groq vs Deepgram vs Google

Choosing a speech-to-text API can be overwhelming. Pricing structures vary wildly, accuracy claims are hard to verify, and features differ between providers. This guide compares the major transcription APIs with real pricing data, verified accuracy benchmarks, and honest assessments of their strengths and weaknesses.

Quick Comparison Table

*Local Whisper is free for processing but requires your own hardware (GPU recommended for speed).

Detailed Provider Breakdown

1. Local Whisper (Free)

OpenAI Whisper is open-source and runs entirely on your device. This is Speakly's default mode.

• Cost: Free (your electricity and hardware)
• Speed: 1-32x real-time depending on model and GPU
• Privacy: 100% local—audio never leaves your device
• Languages: 99 languages supported
• Accuracy: 5-10% WER depending on audio quality

Best for: Privacy-focused users, offline needs, high-volume use where API costs would add up.

2. Groq Whisper API

Groq runs Whisper on their custom LPU (Language Processing Unit) hardware, achieving unprecedented speed.

• Whisper Large V3 Turbo: $0.04/hour (216x real-time)
• Whisper Large V3: $0.111/hour (299x real-time)
• Distil-Whisper English: $0.02/hour (fastest, English only)
• Minimum charge: 10 seconds per request
• File limit: 100MB via URL upload

Groq offers a 50% discount for batch processing (non-urgent jobs processed within 24 hours).

Best for: Budget-conscious cloud users who want Whisper quality at the lowest price. The speed is remarkable—a 1-hour audio file transcribes in about 12 seconds.

3. Deepgram Nova-2

Deepgram builds their own models optimized for different use cases.

• Pre-recorded batch: $0.0043/minute (~$0.26/hour)
• Streaming real-time: $0.0059/minute (~$0.35/hour)
• Languages: 36 languages
• Free credits: $200 for new accounts (~45,000 minutes)
• Special models: Meeting, phone call, medical variants

Deepgram's standout feature is streaming transcription with very low latency. They also include smart formatting (capitalization, punctuation) and paragraphs by default.

Best for: Real-time applications, meeting transcription, phone call analysis, medical transcription.

4. OpenAI Whisper API

OpenAI's hosted Whisper is the simplest option—same model as local, but cloud-hosted.

• whisper-1: $0.006/minute (~$0.36/hour)
• gpt-4o-transcribe: $0.006/minute (with diarization)
• gpt-4o-mini-transcribe: $0.003/minute (50% cheaper)
• Languages: 99 languages
• File limit: 25MB per request
• Region options: Global, US, EU endpoints

Best for: Developers already using OpenAI, those who want simplicity and reliability without managing infrastructure.

5. ElevenLabs Scribe

ElevenLabs Scribe claims the highest accuracy (96.7% for English) and includes advanced features.

• Standard: $0.40/hour
• Languages: 99 languages
• File limit: 3GB, up to 10 hours
• Diarization: Built-in speaker identification
• Audio events: Detects laughter, applause, music

Scribe v2 Realtime offers 150ms latency for live transcription—among the fastest real-time APIs available.

Best for: Applications requiring maximum accuracy, podcast transcription, content with multiple speakers.

6. Mistral Voxtral (NEW)

Mistral Voxtral is the newest entrant, offering competitive pricing and open-source weights.

• Voxtral Mini: $0.001/minute (~$0.06/hour)
• Voxtral Small: $0.002/minute (~$0.12/hour)
• Languages: 97 languages
• Max audio: 30 minutes per request
• Open source: Apache 2.0 license, available on Hugging Face

Mistral claims 97% accuracy with Voxtral, competing directly with Whisper. The open-source nature means you can also self-host for truly local processing.

Best for: Budget-conscious users at scale, open-source advocates, those who want to self-host a non-Whisper model.

7. Google Cloud Speech-to-Text

Google Cloud STT offers extensive language support and enterprise features.

• Standard: $0.016/minute (~$0.96/hour)
• Enhanced/Chirp: $0.024-0.036/minute
• Data logging opt-out: +40% price
• Free tier: 60 minutes/month
• Languages: 125+ languages (best coverage)

Best for: Enterprise deployments, rare languages not supported elsewhere, integration with other Google Cloud services.

Cost Comparison: 100 Hours/Month

What would 100 hours of transcription cost monthly with each provider?

At scale, the differences are dramatic. A heavy user (1,000 hours/month) would pay $40 with Groq vs $960 with Google—a 24x difference.

Accuracy Benchmarks

Word Error Rate (WER) measures transcription accuracy—lower is better. Based on Artificial Analysis benchmarks and provider claims:

Note: Real-world accuracy depends heavily on audio quality, accents, and domain. Clean podcast audio will perform better than noisy phone calls.

Feature Comparison

*OpenAI diarization available with gpt-4o-transcribe model. **Mistral Voxtral is open-source and can be self-hosted for offline use.

Which Provider Should You Choose?

• Privacy-first? → Local Whisper (free, offline, your data stays yours)
• Cheapest cloud? → Mistral Voxtral ($0.06/hour, open-source)
• Fastest cloud? → Groq ($0.04-0.11/hour, 200x+ real-time speed)
• Real-time streaming? → Deepgram or ElevenLabs (low latency APIs)
• Maximum accuracy? → ElevenLabs Scribe (96.7% English accuracy)
• Enterprise/rare languages? → Google Cloud (125+ languages, compliance)
• Simple integration? → OpenAI (if you already use their APIs)

Using BYOK with Speakly

Speakly supports all these providers through BYOK (Bring Your Own Key). This gives you:

• Unified interface — Same UI regardless of backend provider
• Easy switching — Change providers without changing workflow
• Local default — Fall back to local processing when offline
• Cost control — Use your own API keys, pay only what you use
• Provider flexibility — Use Groq for dictation, Deepgram for meetings

To configure BYOK: Settings → Transcription → Cloud Provider → Enter your API key.

Conclusion

There's no single "best" provider—it depends on your priorities. For most users, we recommend starting with local Whisper (free, private) and adding Groq as a cloud backup for speed-critical situations. This combination gives you the best of both worlds: privacy by default, cloud speed when you need it.