Comparison

iA Writer vs Second Brain Joiner

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

Head to head
About

iA Writer

A distraction-free writing environment designed to help you focus on your words. It offers features like Focus Mode, plain text writing with HTML preview, and robust organization tools. Customize your writing experience and export to various formats.

Highlights
  • Distraction-free writing environment
  • Focus Mode for enhanced concentration
  • Plain text writing with HTML preview
  • Document organization and search
  • Customizable keyboard layout
  • Export to various formats (Word, PDF, HTML, WordPress, Medium)
Currently charting
Read full description

“Leaving life’s mess for an ideal realm of words.” —The New Yorker “My favorite iOS app for writing in Markdown, without question, is iA Writer. iA Writer is just beautiful. To me, it’s the gold standard for Markdown syntax styling... an elegant champagne flute. That’s iA Writer for me.” —John Gruber “iA Writer creates a clean, simple and distraction-free writing environment for when you really need to focus on your words.” —The New York Times “iA Writer is an example of how powerful simplicity and accessibility can be.” —The Guardian “iA Writer is all about textual production—writing this phrase, this sentence, this word at this moment.” —WIRED 4 x Best of App Store Winner # The Simple Writing App iA Writer removes distractions. Giving you a calm, focused, writing space, so you can express yourself clearly. # Focus Focus Mode dims everything but the current sentence or paragraph, helping you stay in the flow. # Start Don’t worry about the format. First, write in plain text. Then preview in HTML. # Organize Search, sort, and quickly swap between documents from different clouds. # Customize When you tap and hold a key in the command keyboard, you’re given the chance to choose your own layout. Rearrange your keys, or pick new ones from the extensive list. # Search You can open documents and launch frequent actions in no time with the new Quick Search. It lives in the keyboard so it’s always close at hand. # Work iA Writer includes an inverted light-on-dark-mode, perfect for working day and night. # Clean Spot superfluous adjectives, weak verbs, repetitive nouns, false conjunctions and clean your text of the usual rumble. # Shape Customize your templates and export to WordPress or Medium, HTML, Microsoft Word (.docx), or PDF. # 100% Text Embed links, pictures, tables and text files in plain text and see them in preview. # Get in Touch - Visit ia.net/writer for more information - Visit ia.net/writer/support for support and feedback

About

Second Brain Joiner

This tool optimizes AI input by merging and formatting Markdown notes. It intelligently filters content, calculates optimal chunk sizes for AI context windows, and maintains original file structure for enhanced AI accuracy and security.

Highlights
  • Advanced filtering by tags and dates
  • High-precision token calculation
  • Smart chunking for AI context limits
  • Local-first absolute security
  • Folder structure maintenance
  • Timestamping for context
Features
Read full description

A professional-grade input optimization tool designed to push your AI's potential to the absolute limit. "Second Brain Joiner" is an application that seamlessly formats and merges your vast collection of Markdown files (your "Second Brain") stored on your device into a single context that AI can easily understand. While modern AI possesses incredible reasoning abilities, it doesn't know your "past context." However, blindly feeding it all your files isn't the solution either. If the amount of information exceeds the context window (the AI's memory limit), the AI becomes confused and generates "hallucinations" (plausible lies). This app was designed to solve that exact problem flawlessly. [Core Features & The Value of the PRO Spec] ◆ 1. Advanced Filtering (Enhancing Context Purity) You no longer need to give the AI "all your memories." By specifying tags or modification dates, you can smartly extract only the context relevant to the problem you want to solve right now. Eliminate noise and deliver 100% pure knowledge to your AI. ◆ 2. High-Precision Token Calculation & Smart Chunking Automatically splits (chunks) files into optimal sizes tailored to your AI's limits. Through highly accurate token estimation, even a massive vault with thousands of files can be processed without errors, dramatically improving the accuracy of your AI's responses. ◆ 3. Local-First Absolute Security Your thoughts belong to you alone. This app does not send data to external cloud servers; all merging and splitting processes are completed entirely within your device's local environment. You can securely process highly confidential business documents or personal diaries. ◆ 4. Folder Structure Maintenance & Timestamping It doesn't just connect text. It automatically inserts the original folder path and last modified date at the beginning of each file. This allows the AI to accurately grasp the timeline and hierarchical structure—"what project this is and when it was written"—before making advanced inferences. [Recommended for:] Prompt engineers and researchers who structure their daily knowledge using Markdown. Those who want to feed their past notes to AI to create a dedicated brainstorming and strategic partner. Those who demand the highest possible accuracy and minimal hallucinations from AI responses. Turn your "Second Brain" into the ultimate engine for your AI. Experience the breakthrough in intellectual productivity brought to you by H.I. MET ARCHITECT.

Screenshots

iA Writer4 screens
Second Brain Joiner4 screens

Verdict

The call

The clearest difference is price: Second Brain Joiner at $3.99 against iA Writer's $19.99. Second Brain Joiner also leads on review sentiment (100% vs 73%). iA Writer's advantage is chart position (#42 vs unranked) and iOS requirement (15.0 vs 18.2). On update cadence, ads, in-app purchases and monetization model 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

iA Writer costs $19.99 and Second Brain Joiner $3.99 up front. Neither carries in-app purchases, so what you see is what you pay.

UpkeepUpdate frequency

iA Writer ships an update fortnightly, Second Brain Joiner every 3 weeks. The most recent releases landed on October 21, 2026 and October 8, 2026 respectively.

Scorecard4 real differences · 7 level
iA Writer versus Second Brain Joiner: the parameters behind the verdict, then further details
ParameteriA WriterSecond Brain Joiner
Price$19.99$3.99 — better
Rating4.6 (1.5K ratings) — better—
Positive reviews73.1% of reviews100.0% of reviews — better
Number of ratings1.5K — better—
Update frequencyFortnightly — betterEvery 3 weeks
AdsNoNo
In-app purchasesNoNo
MonetizationPaidPaid
Best chart rank#42 — better—
DevicesiPhone, iPad, iPod — betteriPhone, iPad
Requires iOS15.0 — better18.2
Further details — not scored
Size65 MB11 MB
Age rating4+4+
DeveloperInformation Architects AGHirofumi Inoue

Customer experience

iA Writer

All ratings1,539 ratings
Positive88.4%
Neutral3.4%
Negative8.3%
Written reviews1,012 reviews
Positive73.1%
Neutral9.2%
Negative17.7%

Second Brain Joiner

Written reviews1 reviews
Positive100.0%
Neutral0.0%
Negative0.0%

Bugs and requests

iA Writer

Reported bugs

3 issues
  • Crashes when opening certain files
  • Sync issues leading to data loss
  • Formatting problems when exporting to other formats

Requested features

6 requests
  • Improved cloud storage integration (Dropbox, Google Drive, etc.)
  • Enhanced file management and organization tools
  • Better text selection and cursor control
  • More customization options for appearance and layout
  • Integrated outline/table of contents view
Show 1 more
  • Collaborative editing features

Second Brain Joiner

Not enough reviews yet to summarise bugs or requests.

In-app purchases

None

iA Writer

No in-app purchases

None

Second Brain Joiner

No in-app purchases

Questions

Is iA Writer free?
iA Writer costs $19.99, with no in-app purchases.
Is Second Brain Joiner free?
Second Brain Joiner costs $3.99, with no in-app purchases.
Do iA Writer or Second Brain Joiner have ads?
Neither iA Writer nor Second Brain Joiner shows ads.
Which is updated more often, iA Writer or Second Brain Joiner?
iA Writer ships an update fortnightly, and Second Brain Joiner every 3 weeks. Most recently, iA Writer was updated on October 21, 2026 and Second Brain Joiner on October 8, 2026.

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