Comparison

Oovium vs Kihya Memo

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

Oovium

This app is a novel calculation sandbox that combines the functionality of calculators, spreadsheets, concept maps, and programming languages into a single, visually intuitive interface. It aims to make complex computing abilities accessible to a wider audience through explicit visual representations.

Highlights
  • Calculation sandbox
  • Visual programming interface
  • Spreadsheet functionality (GridBub)
  • Concept mapping (TextBub)
  • Custom function definition (MechBub)
  • Object instances (InstBub)
Features
Read full description

Oovium makes my geek heart flutter. - Anne Wind This app is a thing of beauty. - W Smith Jr Wow I love this - OkeyMor57 22nd century calculating - bill knighton This will become Hari Seldon’s Prime Radiant some day. - nicked off Oovium is not an attempt to rehash old outdated inventions, but it subsumes much of their functionality. The calculator, spreadsheet, concept map, programming language: Oovium is all of them and it's none of them. Oovium is the first (but certainly not the last) of an entirely new class of app, the calculation sandbox. It has been made possible by the invention of the touch device and Oovium's clean, efficient and tactile interface, designed for such devices, has been part of its DNA since its inception. At its heart, Oovium aspires to make powerful, sophisticated and complex abilities (such as those currently available only to programmers) accessible to a wider audience. Oovium understands that increasing accessibility does not mean dumbing down an application by hiding complex functionality, it means making that complex functionality understandable by creating explicit visual representations for it. The workspace of Oovium is a two-dimensional surface known as the Aether. Upon this aether a user can place Bubbles. There are currently four types of bubbles: - InstBub is an instance of an object, usually a number, which in turn may be the result of an expression. - MechBub allows the user to define their own functions. - GridBub allows for a tabular arrangement of numbers and expressions similar to a spreadsheet. - TextBub is a node that can be connected to other TextBub nodes in order to create concept maps. These bubbles can be connected to each other in order to render sophisticated calculations in a visual (and aesthetic) way. Libraries of custom functions can be developed and included in other aethers when needed. The concept of Oovium has six different aspects; in its current form it contains only one of these six aspects. It is a highly ambitious project with much more planned, that hopes to empower users; it hopes to change the way people think about and work with their computers; in short, it hopes to change the world! Come help drive its functionality; come help make Oovium happen!

About

Kihya Memo

Features
Read full description

Kihya Memo is a lightweight, offline-first Markdown notepad. Write the source directly, use focused formatting tools, and switch to a beautiful native preview while every note remains a file you can keep. Markdown is the heart of the app. When needed, the same plain-text editor also opens safe UTF-8 text and source documents without converting them to a proprietary database. There is no Kihya account to create and no required Kihya memo server. Google Drive sync and remote server folders are optional. KEY FEATURES • Switch instantly between Markdown source and native preview • Toggle task checkboxes directly in preview • Use focused Markdown tools for headings, lists, bold, italic, strike, code, links, attachments, and underline • Convert pasted rich text into clean Markdown • Create, edit, rename, move, and share HTML, JSON, XML, CSV, PHP, ASP, JavaScript, SQL, and other UTF-8 text or source files when needed • Live syntax colors and line numbers without adding formatting to the file • Static HTML/SVG, pretty JSON/XML, table, calendar, contact, and color-source previews • Plain-text copy and paste for code; rich-text conversion only inside Markdown • Import photos, PDFs, archives, and other files from Photos or Files • Drag, rename, move, and safely remove nested folders in a dedicated manager • Search file names and full note contents • Find, Replace, and Replace All from the title menu, with case options, regex, and capture groups • Choose Save, Discard Changes, or Keep Editing when leaving an unsaved note • Move, rename, trash, or open past versions from the title menu • Open Recently Deleted from the folder list to restore items to their original location or delete them permanently • Optionally protect Recently Deleted with Face ID, Touch ID, or the device passcode • Keep pre-save versions locally and load one into the editor without saving it immediately • Recover the latest local edit draft after an unexpected app termination • Optional marker-texture highlighting for bold and underlined preview text • Preview local images and open clearly marked local-file links • Open and share editable text, source documents, and stored files through the system Files app • Optionally sync original files through a visible app folder in your own Google Drive • Add SFTP, plain FTP, explicit FTPS, or implicit FTPS servers as remote folders, with local recovery drafts, history, conflict detection, and verified saves • Export the visible folder tree as a ZIP without trash or private history • Start writing instantly from a resizable Quick Note Home Screen widget • See a sourced daily thought matched to morning, afternoon, evening, or night • Continue writing beneath a thought and share it as a 4:5 image card • Open a favorite document in full-screen reading mode from the Home Screen • Five bundled Korean typefaces in addition to the system font • Native phone navigation and an iPad three-pane or full-screen editor PRIVACY BY DESIGN • No Kihya sign-up or required login • No ads or cross-app tracking • Google Drive connects only when you choose it; notes are never sent to a Kihya server • Remote connections go directly from your device to the server you enter; credentials use device-only protected storage and remote contents, hosts, paths, and user names are excluded from analytics • SFTP and FTPS are encrypted. Plain FTP is visibly marked and requires a separate warning because its credentials, file names, and contents are not encrypted • Firebase usage events never include note text, file names, searches, or Google account details • Access is limited to local files and files the user explicitly selects • Normal history and recovery drafts stay on device; pre-overwrite sync text is also protected in hidden app data in your Drive

Screenshots

Oovium4 screens
Kihya Memo4 screens

Verdict

The call

The clearest difference is update cadence: Kihya Memo at daily against Oovium's every 6 weeks. On price, ads, in-app purchases 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

CostPrice · In-app purchases · Ads · Monetization

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

UpkeepUpdate frequency

Oovium ships an update every 6 weeks, Kihya Memo daily. The most recent releases landed on October 17, 2026 and October 2, 2026 respectively.

Scorecard1 real difference · 9 level
Oovium versus Kihya Memo: the parameters behind the verdict, then further details
ParameterOoviumKihya Memo
PriceFreeFree
Rating5.0 (5 ratings) — better—
Positive reviews64.7% of reviews—
Number of ratings5 — better—
Update frequencyEvery 6 weeksDaily — better
AdsNoNo
In-app purchasesNoNo
MonetizationFree—
DevicesiPhone, iPad, MaciPhone, iPad, Mac
Requires iOS17.016.0 — better
Further details — not scored
Size10 MB33 MB
Age rating4+4+
DeveloperAepryus SoftwareKihya

Bugs and requests

Oovium

Reported bugs

134 issues
  • Subscription not working
  • Crashes on launch on iPad
  • Links to Dropbox no longer work
  • Update killed everything, crashes on first screen
  • Crashes regularly
Show 129 more
  • App crashes at launch
  • Crashes and lost data before saving
  • Crashes a few times on first use
  • Struggled to get rid of help demo
  • Crashes regularly and feels like a work in progress
  • On-screen hints don't rotate with screen orientation
  • Crashes very frequently
  • Cannot get an aether saved
  • App exits and data is gone
  • Redone calculations multiple times
  • Crashes at launch
  • Launch, crash, launch, crash
  • Splash screen up for a fraction of a second
  • Crashed 5 times in 15 minutes
  • Crash-prone
  • Keeps crashing
  • Is it this update?
  • Forum has no entries since September
  • App still supported/under development?
  • Testing of releases could be better
  • Crashes on start
  • Unusable
  • Landscape mode reverts to portrait
  • Attempts to remove bubble cause a crash
  • Problem with online forum
  • Forum in its infancy
  • Background fades slowly
  • No audio feedback option
  • No statistical functions
  • Too difficult to move and link bubbles
  • Help documentation nonexistent
  • No array of numbers from spreadsheet or data table
  • No zoom
  • No scrollbars
  • Black background poor choice
  • No labels for boxes
  • No separation in box between references and numbers
  • Can't move a box once it's down
  • No visual sign of connections like lines
  • Needs more functions
  • Hard to use and get lost
  • Trippy version of Apple calc
  • Odd to use
  • Subscription is paid but app not usable
  • Mac app not clear, tutorial for iOS only
  • Subscription not automatically renewed
  • App crashes on launch
  • App hasn't been updated in a long time
  • App hasn't kept up with iOS changes
  • Dropbox links no longer work
  • Crashes on launch on iPad
  • Update killed everything
  • Crashes on first screen
  • Crashes regularly
  • Feels like a work in progress
  • Implementation not intuitive enough
  • On-screen instructions are clunky
  • On-screen hints don't rotate
  • Odd, unwieldy interface
  • Tutorial limited to making bubbles
  • Lacks comprehensive help files
  • Video-based information useless for some
  • Interface prevents features from being used
  • Crashes regularly
  • Tedium
  • Custom UI elements instead of standard iOS
  • Not ready for prime-time
  • No statistical functions
  • Too difficult to move and link bubbles
  • Help documentation basically nonexistent
  • No ability to use an array of numbers from a spreadsheet or data table
  • Can't save a calculation web and reuse it
  • Can't zoom in
  • Interface isn't intuitive
  • Can be quite frustrating to begin with
  • Crashes very frequently
  • Can't get an aether saved
  • Once the app exits, it's gone
  • Redone the same calculations 3 times
  • Crashes at launch
  • Launch, crash, launch, crash
  • Splash screen up for a fraction of a second
  • Crashed 5 times in the last 15 minutes
  • GUI needs to be slicker and more polished
  • Crashed a few times on first use
  • Struggled to get rid of the help demo
  • Certain aspects are portrait orientation only
  • In app documentation is terribly lacking
  • Crash-prone
  • Documentation could be much better
  • Managed to crash it 5 times in the last 15 minutes
  • Lack of stability and good documentation
  • Beta at best right now
  • Keeps crashing
  • Is it this update?
  • Could do with a comprehensive set of instructions
  • Forum has no entries since September
  • Is this app still supported/under development?
  • Testing of releases could be better
  • Crashes on start
  • Unusable
  • Landscape mode reverts to portrait
  • Attempts to remove the offending bubble also cause a crash
  • In-app help is very sketchy
  • Price seems high for what seems more like an alpha version than a stable release
  • Limited in-app help
  • Problems with online forum
  • Needs Undo / Redo
  • Needs centering
  • Needs cut/paste formula
  • Needs colors
  • Needs search and save
  • Background fades slowly
  • No audio feedback option
  • No statistical functions
  • Too difficult to move and link bubbles
  • Help documentation is basically nonexistent
  • No ability to use an array of numbers from a spreadsheet or data table
  • No zoom
  • No scrollbars
  • Black is a poor choice of background color
  • No labels for boxes
  • No separation in a box between references from other boxes and numbers entered directly
  • Can't move a box once it's down
  • No visual sign of connections like lines
  • Needs more functions
  • Hard enough to use and once it is set up you get lost quickly
  • Trippy version of the apple calc
  • Kinda odd to use

Requested features

75 requests
  • Better terminology
  • Vastly better documentation
  • Pay-once option
  • Lower purchase price ($3.99 or less)
  • Graphing and graphics capabilities
Show 70 more
  • Loop structure (other than recursion)
  • Overlay for logic and decision making flow chart shapes
  • Link logic operators to number flow
  • Undo feature
  • Random number generator function
  • Loop structure
  • Better handling of labeling and grouped items
  • Standard iOS interface elements
  • Undo/Redo functionality
  • Centering
  • Cut/paste formula
  • Colors
  • Search and save functionality
  • Fade background faster
  • Audio feedback option (beep-boop sounds)
  • Statistical functions
  • Ability to use array of numbers from spreadsheet or data table
  • Scrollbars for canvas navigation
  • Labels for boxes
  • Separation in box between references and numbers
  • Ability to move a box after placement
  • Visual sign of connections (lines)
  • More functions
  • Zoom functionality
  • Scrollbars
  • Labels for boxes
  • Separation in box between references and numbers
  • Ability to move a box once it's down
  • Visual sign of connections like lines
  • More functions
  • Save calculations and functions
  • Improve UI slickness and polish
  • Remove help demo after first use
  • Add cues and clues for using the interface
  • Use standard iOS interface
  • Add simple titles or tips for objects
  • Guidance on aether list usage
  • Create own objects and make calculations based on them
  • Improve stability and error handling/recovery
  • Improve documentation
  • Add strings, constants, and units
  • Fix landscape mode orientation issue
  • Add Undo/Redo
  • Add centering
  • Add cut/paste formula
  • Add colors
  • Add search and save
  • Fade background faster
  • Audio feedback option
  • Statistical functions
  • Ability to use array of numbers from spreadsheet or data table
  • Zoom functionality
  • Scrollbars
  • Labels for boxes
  • Separation in box between references and numbers
  • Ability to move a box once it's down
  • Visual sign of connections like lines
  • More functions
  • Save calculations and functions
  • Improve UI slickness and polish
  • Remove help demo after first use
  • Add cues and clues for using the interface
  • Use standard iOS interface
  • Add simple titles or tips for objects
  • Guidance on aether list usage
  • Create own objects and make calculations based on them
  • Improve stability and error handling/recovery
  • Improve documentation
  • Add strings, constants, and units
  • Fix landscape mode orientation issue

Kihya Memo

Not enough reviews yet to summarise bugs or requests.

In-app purchases

None

Oovium

No in-app purchases

None

Kihya Memo

No in-app purchases

Questions

Is Oovium free?
Oovium is free to download, with no in-app purchases.
Is Kihya Memo free?
Kihya Memo is free to download, with no in-app purchases.
Do Oovium or Kihya Memo have ads?
Neither Oovium nor Kihya Memo shows ads.
Which is updated more often, Oovium or Kihya Memo?
Oovium ships an update every 6 weeks, and Kihya Memo daily. Most recently, Oovium was updated on October 17, 2026 and Kihya Memo on October 2, 2026.

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