Simple Hidden Note
Why PIN-Based Note Collections
Most notes apps show everything on the home screen: every folder, every notebook, every recent file. Simple Hidden Notes works differently. Your notes are grouped into collections, and each collection is opened by entering a numeric PIN. If you have not explicitly unlocked a collection and given it a visible title, it does not appear anywhere in the interface.
This is not about military-grade encryption. It is about discretion. Some notes simply do not need to be on display every time you open the app.
How It Works
Enter a PIN on the keypad to open a collection.
Write notes inside the collection using plain text or rich text.
Unlock a collection if you want it to stay visible on the home screen with a custom title.
Re-lock it anytime to remove it from the visible list again.
That is the entire mental model. No nested folders, no tagging taxonomy, no workspace setup.
Note Editing
Each note has a title and a body. You can start in plain text and upgrade to rich text when formatting matters. The rich-text editor supports:
Bold, italic, underline, and strikethrough.
Code and blockquote formatting.
Bullet lists, ordered lists, and task lists.
Undo and redo.
Notes can be reordered inside a collection by dragging them. Font size is adjustable for plain-text mode. On web, keyboard shortcuts like Ctrl+S or Cmd+S save instantly.
Auto-Save and Recovery
For unlocked collections, the app auto-saves your work every two minutes and when the app goes to the background. If you return to a note after a crash or accidental close, the auto-saved version can be restored. Unsaved changes trigger a confirmation dialog before anything is discarded.
Sharing and Portability
Your notes are not trapped inside the app:
Copy a single note or its title and body separately.
Share a single note or all notes in a collection as plain text.
Export a collection to a text file.
Import a text file into a collection, including legacy formats.
Offline First
Simple Hidden Notes works fully offline. No account is needed, no internet connection is required. All data is stored locally on the device or in browser storage.
Optional Cloud Sync
When you want backup or cross-device access, you can sign in with email or Google (on web). Sync is manual: you inspect the sync status per collection and explicitly upload or download when you choose. This is not a real-time collaborative system. It is a deliberate sync-when-ready model.
Deep Links
On the web, Simple Hidden Notes supports URL-based links that can:
Open a collection by PIN.
Create a new collection with a title.
Add a note to a collection, or append content to an existing note.
These links are consumed once and removed from the browser URL, so they function as one-time entry points. This makes them useful for automation, handoffs from other tools, or quick-capture workflows.
How It Connects to Other Apps
Simple Hidden Notes fits into a broader family of apps from Next Level Order Engineering:
Containd Kanban, the task planning app, can link any task directly to a note collection via its PIN. Each task can have an associated notes link that opens the relevant collection instantly.
Containd, the inventory app, can launch Simple Hidden Notes with the ID of an inventory item as the PIN, creating a convenient way to attach working notes to cataloged items.
These connections are optional and do not affect the standalone experience.
Honest Boundaries
The PIN hashes collections for addressing, but note content is not encrypted at rest.
The app is discreet, not a security vault. Do not store highly sensitive credentials in it.
Cloud sync uses Firestore. There is no end-to-end encryption on synced data.
Exported files are plain text, not encrypted archives.
Open the web app to start immediately, or download Simple Hidden Notes on Android or iOS. Visit the software page for all links, or subscribe to the newsletter for updates.
