Build a notes or journaling app that works exactly your way

Notes apps are personal infrastructure. The one you use daily should match how you think: folders or tags, plain text or markdown, a daily diary prompt or a blank page. Building your own on App Builder Agent means keeping the two features you rely on and none of the sync subscriptions.

This guide covers a fast notes app, a guided journal, and the details — search, lock, backup — that make an app you keep for years.

The essentials

A notes app is judged in the first five seconds: how fast can I write, and can I find it again?

• Instant new note — Open the app, start typing. Title optional, autosave always.
• Organisation that fits you — Folders, tags, colours, pins — pick one main system and one helper.
• Search that actually searches — Full-text, including inside long notes, with highlighted matches.
• Formatting you will use — Checklists, headings, bold, code — or markdown if that is your habit.
• Lock — A PIN or biometric lock for the whole app or for private notes.
• Backup and export — Export to a zip of markdown files; import back. Your notes must outlive the phone.
• Reminders — A note can be a task: remind me at 5 pm.

Build it with App Builder Agent, step by step

Describe the way you take notes; the agent maps it to screens.

1. Create a mobile app project. Notes want offline storage and a lock — a native app.
2. Describe your system. Say how notes are organised and what the editor supports.
   Build a notes app called Quill. Notes list with pinned notes first, folders in a drawer, tags with colours. Editor with autosave, checklists, headings and bold via a toolbar. Full-text search with highlights. Biometric lock for a “Private” folder. Export all notes to a zip of markdown files and import it back. Everything on the device. Paper-white theme with a dark mode.
3. Write a few notes in the simulator. Try search and the checklist. Ask for changes in plain words: “make the toolbar sticky above the keyboard”.
4. Add reminders and a widget-like Today view. Reminders as local notifications; a Today screen with today’s notes.
   Add reminders per note (date and time, local notification) and a Today tab listing notes created or due today.
5. Install the APK. Export it, and set up the first backup export so you know it works.

Prompts that work well

Different note-takers, different apps:

Make it feel finished

• Autosave on every keystroke; never show a save button.
• Ask for a “recently deleted” folder with 30-day recovery.
• Keep the editor full-width with generous line height; reading matters as much as writing.
• Export as markdown, not a proprietary format.

Your notes, your device

A local-only notes app costs nothing to run and never leaks. When you want the same notes on a laptop, ask the agent for a hosted backend with an account — the platform provisions the database and API for the project — and publish a website version for desktop.

The project stays yours; the next feature is a sentence away.

Frequently asked