Structured Outliner vs Nubble Notes
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Structured Outliner
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Keep your entire outline in a single portable file you control. No account, no server, no lock-in, future-proof. ORGANIZE IN UNLIMITED DEPTH Build trees as deep as you need. Expand, collapse, and reorder topics with just a few taps. Every topic can have its own notes. Write as much or as little as you like. SEARCH EVERYTHING Search titles or note content at once. The tree expands automatically to show every match in context, so you always know where a result lives in your outline. CROSS-LINK TOPICS Link any note to another topic using the outlook: link format. Tap to jump directly there. Tap the back arrow to return where you came from. OPEN FILES AND URLS Tap any file path or URL inside a note to open it. Connect your outline to existing documents in the folder: PDFs, photos, or anything else you reference. COLOR LABELS Assign a background color to any topic: Red, Orange, Yellow, Green, Blue, or Purple. The color flows down to all child topics that don't have their own. Use it to visually separate sections at a glance. AUTOMATIC BACKUPS The app writes a .bak backup before every save. Restore at any time from the menu. SYNC YOUR WAY Store your file in iCloud, Dropbox, Google Drive, or any Files-compatible provider. Open it from there on each device. No special sync setup required. MEMPAD COMPATIBLE Structured Outliner uses the same .lst format as MemPad for Windows, a portable outliner that has been around since the early 2000s. Open existing MemPad files directly, no conversion needed. FREE VERSION Structured Outliner is free to use. Development is supported by a small banner ad shown at the bottom of the screen. PRO VERSION Upgrade to Pro to remove the banner ad, unlock Color Labels and Topic + Note Search and future planned features. One-time purchase. Restore on any device from the menu.
Nubble Notes
Organize your thoughts visually with interconnected bubbles. Nest notes and ideas, tag them with confidence levels, and link related concepts. This app allows for flexible organization that adapts to your thinking process.
- Visual bubble organization
- Nested notes and bubbles
- Multi-bubble note placement
- Confidence tagging system
- Linked idea connections
- Password-protected private bubbles
- Import and search functionality
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Nubble organizes your thoughts in visual bubbles. Create notes, nest them inside your bubbles, tag them by how sure you are, and link related ideas — so your notes reflect how you actually think, not just when you wrote them down. Most notes apps ask you to decide on a structure before you have anything to put in it. Nubble lets the pile exist, then makes it something you can see and move around. Features: Visual bubble organization — bubbles hold notes and other bubbles, as deep as you like One note can live in several bubbles at once, no duplicates Drag and drop to rearrange, with pages that grow as you do Confidence tags: Certain, Think About More, Not Sure, Could Be Wrong — or make your own Link notes with typed connections and jump between them Lock private bubbles behind a password Search, sort, filter, and pin Import existing notes from text or by pasting Dark and light mode Free to use. Start as a guest with everything stored on your device, or sign in to sync across devices.
Screenshots
Verdict
The clearest difference is in-app purchases: Nubble Notes at none against Structured Outliner's 1. Nubble Notes also leads on ads (none vs shown) and iOS requirement (15.0 vs 17.0). On price, update cadence and device support there is nothing between them.
Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS
Both are free to download. Structured Outliner sells 1 one-off in-app purchase. Nubble Notes asks for nothing beyond the download.
Structured Outliner ships an update every 9 days, Nubble Notes every 5 days. The most recent releases landed on September 19, 2026 and September 8, 2026 respectively.
| Parameter | Structured Outliner | Nubble Notes |
|---|---|---|
| Price | Free | Free |
| Rating | — | 5.0 (2 ratings) — better |
| Number of ratings | — | 2 — better |
| Update frequency | Every 9 days | Every 5 days — better |
| Ads | Yes | No — better |
| In-app purchases | Yes | No — better |
| Monetization | — | Free |
| Devices | iPhone, iPad | iPhone, iPad, iPod — better |
| Requires iOS | 17.0 | 15.0 — better |
| Further details — not scored | ||
| Size | 6 MB | 5 MB |
| Age rating | 4+ | 4+ |
| Developer | Felipe Carraro | ADAM JIANG LAI |
In-app purchases
Structured Outliner
- Pro Version$7.99
Nubble Notes
No in-app purchases





