Notesync.md vs Dioptra
Price, ratings, monetisation and update history for both apps, side by side โ with what reviewers say about each.
Notesync.md
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Notesync.md is a simple notes app built for organizing quick project thoughts into folders, notes, and timeline-style entries, then keeping them synchronized across Mac, iPhone, and iPad with iCloud. Notes are also mirrored to the local filesystem as Markdown files, making them easy to read, back up, edit, or use with project management agents and other developer workflows.
Dioptra
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A 3D model viewer for iPhone and iPad that takes measurement seriously. Open a file, turn it over, and tap two points on the surface to get a real distance. FORMATS โข glTF โ .glb and .gltf โข USD โ .usdz, .usdc, .usda and .usd โข STL โ 3D prints and CAD exports, read in millimetres and turned upright โข PLY โ scans and photogrammetry, with per-vertex colour โข VRM โข Interactive pages โ an .html export keeps its own controls and runs as it was built MEASURE โข Tap two points for a true distance โข Take as many measurements as you need; they stay listed with the model โข Switch between metric and imperial whenever you like โข Set what one file unit means: metres, centimetres, millimetres, inches or feet INSPECT โข Orbit, pan and zoom, or leave it turning on its own โข Wireframe, to see how a mesh is built โข Studio, light and dark backgrounds โข Play embedded animations, one clip at a time โข Model info: width, height and depth, plus triangles, vertices, meshes, materials, textures, nodes and animations โข Share a snapshot of the view ORGANISE โข Folders, which appear in the Files app exactly as they do here โข Search, sort by name, type or date, and switch between a list and a grid โข Rename, drag a model onto a folder to file it, or delete it โข Bring models in with the picker, from another app's share sheet, or by dropping them into the Dioptra folder in Files SAMPLES Six models come with the app, one for each kind of file it opens, all built to real-world scale: the ancient sighting instrument the app is named for, a Roman surveyor's groma, a sundial's gnomon, a tripod foot in millimetres, a surveyed patch of terrain, and an interactive plan of sight lines. PRIVATE BY DEFAULT No account, no sign-in, no cloud, no tracking and no ads. Your models stay on your device and everything works offline.
Screenshots
Verdict
The clearest difference is in-app purchases: Notesync.md at none against Dioptra's 3. Notesync.md also leads on update cadence (daily vs fortnightly). On price, ads, device support and iOS requirement there is nothing between them.
Scored on Price ยท Rating ยท Positive reviews ยท Number of ratings ยท Update frequency ยท Ads ยท In-app purchases ยท Monetization ยท Best chart rank ยท Devices ยท Requires iOS
Both are free to download. Dioptra sells 3 one-off in-app purchases. Notesync.md asks for nothing beyond the download.
Notesync.md ships an update daily, Dioptra fortnightly. The most recent releases landed on November 5, 2026 and November 10, 2026 respectively.
| Parameter | Notesync.md | Dioptra |
|---|---|---|
| Price | Free | Free |
| Update frequency | Daily โ better | Fortnightly |
| Ads | No | No |
| In-app purchases | No โ better | Yes |
| Devices | iPhone, iPad, Mac โ better | iPhone, iPad |
| Requires iOS | 17.0 | 17.0 |
| Further details โ not scored | ||
| Size | 2 MB | 5 MB |
| Age rating | 4+ | 4+ |
| Developer | Kristopher Linquist | Zachary Griffin |
In-app purchases
Notesync.md
No in-app purchases
Dioptra
- Small Tip$0.99
- Tip$1.99
- Generous Tip$4.99









