dayink

Privacy Policy

Last updated: June 18, 2026

dayink is a personal diary app that uses AI to draw your day. We designed it from day one to collect as little personal data as possible while still doing what it does. This policy describes what we collect, why, and what you can do about it.

1. What we collect

  • Account: the email address tied to your Google OAuth sign-in.
  • Diary entries: the text you write each day plus the mood you choose. Stored encrypted-at-rest in Supabase Postgres.
  • Generated illustrations: the PNG images we compose from your diary entries. Stored in Supabase Storage. Always private to your account unless you explicitly opt into sharing a page.
  • Appearance preferences (4-panel illustrations): structured choices used to keep the character consistent across your 4-panel pages — gender, age range, hair (color, length, style), whether you wear glasses, outfit style, and an optional short note. Faces are never rendered with detailed features (always shown from behind or with eyes hidden), so this is about wardrobe and silhouette, not likeness. Used solely for personalizing your own 4-panel illustration character; never shown to other users. You can update or clear these preferences at any time from Settings → Profile. Each submitted entry stores its own snapshot of your preferences at the time of submission, so later changes don't alter historic pages.
  • Billing: Polar holds your payment method. We store only the Polar customer + subscription IDs.
  • Optional analytics: only after you accept the consent banner. We capture anonymous interaction events (which buttons you tap, how often). We never log diary text or appearance preferences.

2. How we use your data

  • To generate your daily illustration. For single-panel (tarot) pages we send the diary text to OpenAI (for moderation and scene description) and to Google Gemini via fal.ai (for image rendering). For 4-panel pages we additionally include your appearance preferences in the image-generation prompt so the character stays consistent across the four panels.
  • To send transactional email — a welcome note, payment receipts, and trial-ending notices — via Resend.
  • To process payments via Polar.
  • To monitor errors via Sentry (no diary text ever leaves your device for this).

3. Sub-processors

We use the following service providers to operate dayink:

  • Supabase (database, storage, auth)
  • OpenAI (text moderation, scene description)
  • Google Gemini via fal.ai (illustration rendering)
  • Polar (payments — Merchant of Record)
  • Resend (transactional email)
  • Sentry (error tracking)
  • PostHog (optional analytics)
  • Vercel + Inngest (hosting, background jobs)

4. AI generation providers — what gets sent, what gets kept

Each illustration request sends the following to our AI providers and nothing more:

  • To OpenAI: your diary text (for moderation + scene description). No account identifier or email is attached.
  • To Google Gemini via fal.ai: a derived scene description (single-panel) or a Kishōtenketsu 4-panel storyboard (4-panel), plus the structured appearance preferences when you've picked 4-panel. We do not send your raw diary text to the image model, your email, or any other account identifier.

Image generation is ephemeral — we keep only the resulting PNG (in your private Supabase Storage bucket). No intermediate prompts, embeddings, or model weights are retained outside the per-request response. Per their terms of service, OpenAI and fal.ai do not train models on dayink inputs.

5. Your rights

You can request a data export or delete your account from Settings → Account. The export and the deletion both include your account record, all diary entries (text + mood + per-entry appearance snapshot), all generated illustrations, and your appearance preferences. Account deletion is a 7-day soft-delete: we cancel any active subscription immediately, mark your account for removal, and purge all stored data after 7 days. To withdraw the request, sign back in within the window.

6. Cookies

We use a session cookie for sign-in (essential). Analytics cookies from PostHog only set if you accept the consent banner. You can change your choice anytime from Settings → Privacy.

7. Contact

Questions, concerns, or data requests: contact us or email hello@dayink.app.

Privacy Policy — dayink