Comparison

Runestone Text Editor vs MermaidEditor

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

Head to head
About

Runestone Text Editor

A powerful plain text and code editor for iPhone and iPad. Offers syntax highlighting, line numbers, find and replace, and extensive customization options for developers and writers.

Highlights
  • Syntax highlighting for many languages
  • Customizable themes and fonts
  • Advanced find and replace
  • Line numbers and cursor location
  • Code formatting with Prettier.js
  • Multiple windows on iPad
Features
Read full description

A plain text editor with syntax highlighting, line numbers, search and replace, page guide, and much more. It's like TextEdit but more powerful and optimised for iPhone and iPad. Runestone is made by a single person with a love for text editors and a vision of building the most lightweight text editor for iPhone and iPad that still has the core features for editing code. Features: - Syntax highlighting of many languages including HTML, JavaScript, JSON, Markdown, Swift, Python, PHP, YAML, and many more. - Select one of the twelve standard themes including popular themes like Tomorrow, Dracula, Solarized, and One Dark Pro. - Innovative find and replace for searching and modifying text while still viewing your file. - Choose font and font size, including support for custom fonts imported using another third-party app. - Show the line and column the cursor is located on. - Uses the standard document browser for an experience similar to the Files app. - Quickly navigate to a specific line. - Automatically close opening brackets and quotes. - Multiple windows on the iPad. - Format code using Prettier.js. Supported languages include CSS,HTML, JavaScript, JSON, PHP and more. - Choose text encoding between popular encodings like UTF-8, UTF-16, ISO Latin 1, and many more. - Enable or disable autocorrection, autocapitalization, and smart punctuation. - Set default file extension of new files. - Open files in Runestone from the Share Sheet. - Print documents. Premium features: - Choose between eight app icons. - Show line numbers. - Highlight the selected line. - Increase line height and letter spacing. - Disable line wrapping to allow horizontal scrolling. - Show tabs, spaces, and line breaks using a selected symbol. - Enable page guide at a specific column to easily tell when lines are getting too long. - Add vertical and horizontal overscroll. - Remember the selected language per file. - Save file extensions and filenames that should always be treated as plain text files. - Enable soft tabs and choose the width of the tab character. - Specify whether pressing the tab key should insert a tab or indent the line. - Adjust the scaling of Markdown headings and disable highlighting of code blocks in Markdown. Runestone was built on the open-source framework with the same name. Find more information on the Runestone framework at github.com/simonbs/runestone

About

MermaidEditor

Create and edit diagrams and charts using mermaid-js syntax with real-time preview. Export your creations as PNG or SVG files and share them across all your Apple devices.

Highlights
  • Mermaid-js syntax highlighting
  • Code completion
  • Instant preview
  • Export to PNG/SVG
  • Cross-device editing
  • QuickLook preview extension
Features
Read full description

MermaidEditor is a diagram and chart editor, powered by mermaid-js. And MermaidEditor supports iPhone, iPad and Mac, with one app you can edit diagram everywhere on any device. MermaidEditor supports mermaid-js syntax highlighting and code completion, so it can help writing diagram and chart clearly, easily and quickly. You can also easily export charts as PNG images or SVG files from the editor, or share image to other people with system actions. √ All Platforms - Both Mobile and Desktop platforms supported, you can edit diagram documents on iPhone, iPad or Mac - Document browser based app, easily edit files on device and sync document between devices - Multiple windows ready, it makes the editor more powerful on iPadOS - Keyboard shortcuts ready on iPadOS with keyboard connected √ Powerful Editor - Syntax Highlighting for mermaid-js grammar - Auto Completion in editor helps typing keywords quickly - Code Snippets likes parallel block in sequence diagram makes life easier - Instant Parsing Error indicator for locating syntax error √ Instant Preview - Auto Generated Preview when typing in editor - Zoom and Pan to move preview for checking diagram's detail - With Scroll wheel it can be easily zoom diagram on macOS √ Integrated Extensions - Thumbnail support, every .mmd file will has its own thumbnail when saving file - QuickLook Preview extension helps you preview mermaid document in Files app on iPhone or iPad and Finder on macOS √ Sharing - Save diagram document as its source with .mmd extension - Export diagram to PNG image or SVG file with one click For mermaid-js grammar, please visit https://mermaid-js.github.io/mermaid/ for documentation.

Screenshots

Runestone Text Editor4 screens
MermaidEditor3 screens

Verdict

The call

The clearest difference is review sentiment: Runestone Text Editor at 76% against MermaidEditor's 14%. Runestone Text Editor also leads on price (Free vs $3.99) and rating (4.7 vs 2.3). MermaidEditor's advantage is in-app purchases (none vs 1). On update cadence, ads, device support and iOS requirement 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

Runestone Text Editor is free to download; MermaidEditor costs $3.99 up front. Runestone Text Editor sells 1 one-off in-app purchase. MermaidEditor asks for nothing beyond the download.

ReceptionRating · Positive reviews · Number of ratings

Runestone Text Editor holds the better App Store score, 4.7 against 2.3. That said, the two scores are not equally well evidenced: Runestone Text Editor has 2K ratings behind it against 10, so its average is the more settled of the two. Written reviews point the same way: 76% of Runestone Text Editor's written reviews are positive against 14% of MermaidEditor's.

UpkeepUpdate frequency

Runestone Text Editor ships an update every 2 weeks, MermaidEditor every 3 weeks. The most recent releases landed on October 16, 2026 and October 13, 2026 respectively.

Scorecard7 real differences · 4 level
Runestone Text Editor versus MermaidEditor: the parameters behind the verdict, then further details
ParameterRunestone Text EditorMermaidEditor
PriceFree — better$3.99
Rating4.7 (2K ratings) — better2.3 (10 ratings)
Positive reviews76.0% of reviews — better13.8% of reviews
Number of ratings2K — better10
Update frequencyEvery 2 weeks — betterEvery 3 weeks
AdsNoNo
In-app purchasesYesNo — better
MonetizationFree with in-app purchases — betterPaid
Best chart rank#30 — better#110
DevicesiPhone, iPad, iPod, Vision ProiPhone, iPad, iPod, Mac
Requires iOS15.014.0 — better
Further details — not scored
Size64 MB125 MB
Age rating4+4+
DeveloperSimon B. Støvring基伟 徐

Customer experience

Runestone Text Editor

All ratings1,962 ratings
Positive93.5%
Neutral2.3%
Negative4.1%
Written reviews363 reviews
Positive76.0%
Neutral9.6%
Negative14.3%

MermaidEditor

All ratings10 ratings
Positive30.0%
Neutral0.0%
Negative70.0%
Written reviews29 reviews
Positive13.8%
Neutral13.8%
Negative72.4%

Bugs and requests

Runestone Text Editor

Reported bugs

6 issues
  • Disappearing files
  • Difficulty pasting text
  • Scroll position not saved
  • Hangs on startup
  • Trouble opening large files
Show 1 more
  • Issues after iOS updates

Requested features

6 requests
  • Markdown preview
  • Code folding
  • Syntax highlighting for more languages
  • Ability to run/execute code
  • Multiple file/window support
Show 1 more
  • Improved undo/redo functionality

MermaidEditor

Not enough reviews yet to summarise bugs or requests.

In-app purchases

1 purchases

Runestone Text Editor

One-time1
  • Premium$9.99
None

MermaidEditor

No in-app purchases

Questions

Is Runestone Text Editor free?
Runestone Text Editor is free to download, with in-app purchases available.
Is MermaidEditor free?
MermaidEditor costs $3.99, with no in-app purchases.
Which has better reviews, Runestone Text Editor or MermaidEditor?
Runestone Text Editor is rated higher. Runestone Text Editor averages 4.7 out of 5 from 2K ratings, while MermaidEditor averages 2.3 from 10 ratings.
Do Runestone Text Editor or MermaidEditor have ads?
Neither Runestone Text Editor nor MermaidEditor shows ads.
Which is updated more often, Runestone Text Editor or MermaidEditor?
Runestone Text Editor ships an update every 2 weeks, and MermaidEditor every 3 weeks. Most recently, Runestone Text Editor was updated on October 16, 2026 and MermaidEditor on October 13, 2026.
Which is more popular, Runestone Text Editor or MermaidEditor?
Runestone Text Editor currently peaks at #30 in the App Store charts, and MermaidEditor at #110. Chart position reflects recent download velocity rather than total install base.

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