Overview
AssemblyAI provides high-accuracy speech-to-text with their Universal-1 model, specifically optimized for diverse accents, dialects, and multilingual content. Key Benefits:- 🌍 Accent-optimized - Excellent for non-native English speakers
- 🎯 High accuracy - Universal-1 model trained on diverse datasets
- 🌐 Multilingual - English, Spanish, French, German, Italian, Portuguese, and more
- 🎁 $50 free credits - No credit card required for signup
Free Tier
What You Get
- $50 in credits upon signup
- No credit card required for free tier
- All features included - Universal-1, punctuation, streaming, etc.
- Credits valid for active accounts
Getting Your Free API Key
Visit AssemblyAI
Go to assemblyai.com and click Get Started Free or Sign Up.
Create an account
Sign up with:
- Email address and password
- Or use Google/GitHub sign-in
Verify your email
Check your email for a verification link from AssemblyAI and click it to activate your account.
Find your API key
Your API key is displayed prominently on the Dashboard:
- Look for the API Key section
- Click Copy to copy your key to clipboard
- Or click Show to reveal the full key
Keep your API key private! Don’t share it or commit it to public repositories.
Available Models
Universal-1 (Recommended)
AssemblyAI’s flagship model optimized for accuracy across diverse scenarios: Universal-1 English:- Trained on diverse English accents (US, UK, Australian, Indian, African, etc.)
- Best for: English dictation with any accent
- Supports English, Spanish, French, German, Italian, Portuguese
- Auto-language detection
- Best for: Non-English languages or code-switching
Language Support
AssemblyAI supports multiple languages with auto-detection: Supported Languages:- English - All accents and dialects (US, UK, Australian, Indian, etc.)
- Spanish - Spain and Latin American variants
- French - France and Canadian variants
- German
- Italian
- Portuguese - Portugal and Brazilian variants
- Auto-detect - Automatically identify language being spoken
Configuration in Stenox
Configure language
- English only: Select
English - Other languages: Select
Spanish,French, etc. - Multiple languages: Select
Auto-detect
Features
Accent Optimization
AssemblyAI’s Universal-1 model excels with diverse accents:- Non-native English speakers
- Regional accents (Southern US, Boston, Scottish, etc.)
- International English (Indian, Nigerian, Singaporean, etc.)
- Mixed accent environments
Streaming Transcription
AssemblyAI uses WebSocket streaming for real-time results:- Audio streams to AssemblyAI as you speak
- Processing begins immediately
- Results return in < 1-2 seconds after you stop speaking
Automatic Features
Punctuation:- Automatic periods, commas, question marks
- Natural capitalization
- Sentence structure optimization
- Numbers formatted appropriately (e.g., “twenty-five” → “25”)
- Dates and times formatted correctly
- Currency and units handled intelligently
Performance
Expected processing times with AssemblyAI:| Recording Length | Processing Time |
|---|---|
| 5 seconds | < 1 second |
| 10 seconds | 1-2 seconds |
| 30 seconds | 2-3 seconds |
| 60 seconds | 3-4 seconds |
AssemblyAI is optimized for streaming, so longer recordings don’t significantly increase processing time.
Usage Tracking
Monitor your credit usage in the AssemblyAI Dashboard:- Visit assemblyai.com and log in
- Go to Dashboard
- View:
- Remaining credits ($50 initially)
- Usage this month
- Detailed transcription logs
Privacy Considerations
What AssemblyAI sees:- Your audio is sent to AssemblyAI servers for processing
- Audio and transcripts may be logged for quality improvement
- Data is encrypted in transit (HTTPS/WSS)
- AssemblyAI offers data retention control options
- Use WhisperKit (local) for 100% offline processing
- Or review AssemblyAI’s privacy policy and configure data retention settings
When to Use AssemblyAI
Non-native accents
Optimized for diverse English accents and dialects.
Multilingual use
Supports multiple languages with auto-detection.
Reliable accuracy
Consistent quality across different speakers and environments.
Cost-effective cloud
Affordable pricing ($0.0009/min) after free credits.
Troubleshooting
API key not working
API key not working
- Verify you copied the complete key from AssemblyAI Dashboard
- Check that your account is verified (email confirmation)
- Try generating a new API key in the Dashboard
- Ensure no extra spaces or characters were added
Transcription fails or errors
Transcription fails or errors
- Check your internet connection
- Verify you have remaining credits in Dashboard
- Ensure audio is being captured (check Stenox recording overlay)
- Try a shorter test recording first
Poor accuracy for your accent
Poor accuracy for your accent
- AssemblyAI is generally excellent with accents, but try:
- Speaking slightly more clearly
- Reducing background noise
- Using a better microphone
- Adding custom vocabulary in Stenox
- Compare with DeepGram or WhisperKit for your specific accent
Wrong language detected (auto-detect)
Wrong language detected (auto-detect)
- Instead of auto-detect, manually select your language in Stenox profile settings
- Speak longer phrases (auto-detect needs more context)
- Ensure you’re using Universal-1 Multilingual model
Pricing After Free Credits
Once your $50 in credits are used:| Feature | Price |
|---|---|
| Standard transcription | $0.0009 per minute |
| Per hour | ~$0.054 per hour |
- 1 hour per day = ~$1.62/month
- 30 minutes per day = ~$0.81/month
Comparison: AssemblyAI vs Others
| Feature | AssemblyAI | DeepGram | WhisperKit |
|---|---|---|---|
| Provider cost | $50 free credits | $200 free credits | No cost (local) |
| Speed | Fast (1-2s) | Fastest (< 1s) | Medium (3-5s) |
| Accent handling | Excellent | Very Good | Good |
| Multilingual | 6 languages | 30+ languages | 100+ languages |
| Privacy | Cloud | Cloud | 100% local |
| Ongoing cost | $0.0009/min | $0.0125/min | Free |
Next Steps
Add AI Enhancement
Enhance transcripts with grammar correction and formatting.
Create Profiles
Different providers for different apps or use cases.
Free Tier Guide
Maximize free usage across all providers.
Add Vocabulary
Improve accuracy with custom words and terms.

