FAQ
General
Section titled “General”What is the Feynman Technique?
Section titled “What is the Feynman Technique?”The Feynman Technique, named after physicist Richard Feynman, is a four-step learning method:
- Choose a concept to learn.
- Explain it in plain language as if teaching a child or beginner.
- Identify gaps — wherever your explanation stumbles, that’s what you don’t know yet.
- Go back to the source material and fill those gaps, then repeat.
Teachback automates step 2 and 3 using voice recording and AI.
Is Teachback free?
Section titled “Is Teachback free?”Yes. The Free tier gives you 50 cloud AI sessions per month and unlimited local (offline) sessions.
Paid tiers unlock higher-quality AI models and unlimited cloud sessions.
Do I need an account?
Section titled “Do I need an account?”No account is required for core features.
Optional sign-in (Apple or Google) lets you sync your learning history across devices — coming in a future update.
Which languages are supported?
Section titled “Which languages are supported?”All languages supported by the Whisper AI model work for transcription.
The AI question-generation is most accurate in English, but Gemini/GPT-4o/Claude all handle multi-language sessions well.
Privacy & Data
Section titled “Privacy & Data”Does Teachback record and store my voice?
Section titled “Does Teachback record and store my voice?”No. Voice recording happens entirely on-device. The audio is fed to the local Whisper model, converted to text, and then discarded. Raw audio is never stored or uploaded.
Where is my data stored?
Section titled “Where is my data stored?”All session data (transcripts, mastery scores, reports) is stored in a SQLite database on your device.
If you sign in with Apple or Google, a future sync feature will optionally back up your history to encrypted cloud storage.
Is Teachback GDPR-compliant?
Section titled “Is Teachback GDPR-compliant?”Yes. The core app processes all personal data (voice, learning history) locally on-device.
When cloud AI is used, your transcribed text is sent to the AI provider under their data processing terms (Google, OpenAI, or Anthropic).
See our Privacy Policy for the full data flow.
AI & Models
Section titled “AI & Models”Which AI model does Teachback use?
Section titled “Which AI model does Teachback use?”It depends on your tier:
- Free — Gemini 2.5 Flash Lite
- Standard — Gemini 2.5 Flash
- Pro — GPT-4o
- Ultimate — Claude (Anthropic)
You can also bring your own API key (BYOK) or use a local Ollama model.
Can I use Teachback without an internet connection?
Section titled “Can I use Teachback without an internet connection?”Yes — with Ollama. Configure a local Ollama server (see the Ollama guide) and the app will route all AI requests there.
Speech-to-text always works offline using on-device Whisper.
What is BYOK?
Section titled “What is BYOK?”BYOK (Bring Your Own Key) means entering your own API key from OpenAI, Anthropic, or Google.
When a BYOK key is saved, Teachback bypasses the cloud worker and calls the provider directly.
This removes the monthly session quota. See the BYOK guide.
Whisper Models
Section titled “Whisper Models”What is the difference between the Whisper model tiers?
Section titled “What is the difference between the Whisper model tiers?”| Tier | Size | Notes |
|---|---|---|
| Base | ~150 MB | Bundled with the app; fastest |
| Small | ~490 MB | Most users; good balance of speed and accuracy |
| Medium | ~1.5 GB | Better for non-English languages |
| Large v3 | ~3.1 GB | Highest accuracy; requires storage |
Models are downloaded on demand from the Settings screen.
Why is the first transcription slow?
Section titled “Why is the first transcription slow?”The first session after launching the app initialises the Whisper model in memory.
Subsequent sessions in the same app session are much faster.
The Settings screen shows a “Local AI loading…” indicator during warm-up.
Subscriptions & Billing
Section titled “Subscriptions & Billing”Can I cancel anytime?
Section titled “Can I cancel anytime?”Yes. Subscriptions are month-to-month and can be cancelled at any time from the App Store or Google Play subscription settings.
Cancellation takes effect at the end of the current billing period.
What happens to my data if I cancel?
Section titled “What happens to my data if I cancel?”All your local session data remains on your device regardless of subscription status.
You revert to the Free tier with 50 cloud sessions per month.