I Built a #1 App Store Developer Tool in Pure SwiftUI — Here's What I Learned

I got tired of jumping between browser tabs every time I needed
to format JSON, convert a color, test regex, or hash a string.
So I spent 6 months building a fix.

The result: Devly — a native macOS menu bar app with 50+
developer utilities. It just hit #1 in Developer Tools on the
App Store.

The Problem I Was Solving

Every developer knows the pain. You need to:

• Quickly format some JSON
• Convert a hex color to RGB
• Test a regex pattern
• Decode a Base64 string
• Generate a UUID

So you open a browser tab. Then another. Then another.
Context switching kills your flow.

What I Built

Devly sits in your macOS menu bar. One click gets you instant
access to 50+ tools:

• Encoding: Base64, URL, HTML, JWT, Unicode, Morse, ROT13
• Hashing: MD5, SHA-256/384/512, HMAC, bcrypt, UUID generator
• Formats: JSON, YAML, XML, CSV, SQL, TOML
• Web Dev: Color converter, CSS/JS minifier, Markdown preview
• Text: Regex tester, diff tool, case converter, timestamp converter

The Technical Challenges

1. Apple's App Sandbox

The biggest hurdle was getting all 50+ tools to work within
Apple's strict sandbox rules. Every tool that processes data
locally has to comply — retrofitting this late in development
was painful. Lesson: plan for sandbox compliance from day one.

2. Keeping the UI Truly Native

SwiftUI on macOS is still maturing. Getting the menu bar
popover to feel truly native — proper sizing, smooth
transitions, correct macOS conventions — required constant
referencing of Apple's Human Interface Guidelines.

3. Managing State Across 50+ Tools

I used a ToolProtocol pattern that each tool conforms to:

protocol ToolProtocol {
    var id: String { get }
    var name: String { get }
    var category: ToolCategory { get }
    func process(input: String) -> String
}

This kept everything consistent and made adding new tools
much faster.

4. Discoverability

With 50+ tools, finding the right one fast became a UX problem.
I built a custom SearchService that indexes tools by name,
category, and keywords.

What I'd Do Differently

• Plan for sandbox compliance from day one
• Build the ToolProtocol pattern earlier
• Study the macOS HIG before writing any UI code
• Test SwiftUI popovers on macOS early — they're quirky

The Result

6 months of nights and weekends. #1 in Developer Tools on
the App Store. Pure SwiftUI, fully
sandboxed, $4.99 one-time.

App Store

Website
All 50+ tools

What challenges have you hit building native macOS apps
in SwiftUI? Would love to hear in the comments!