Building a Private AI Diary with On-Device Speech Transcription

Short summary

A design walkthrough of a voice journal app for iPhone that uses on-device speech transcription and server-side AI organization. The key design decision is keeping transcription local while sending only the current transcript for AI organization — not the full diary archive. The article argues for precise privacy language over sweeping promises and shows how to structure AI output into predictable fields like diary sections, todos, and reminders.

• •On-device transcription keeps raw audio local; only current transcript is sent for AI organization
• •Precise privacy boundaries are more useful than vague 'private' claims
• •AI organization should correct errors, separate actions from reflection, and avoid inventing facts

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