Sparkle Auto-Update for macOS Apps

This skill adds Sparkle auto-update support to a native macOS app. Sparkle is the standard open-source framework for macOS app updates outside the Mac App Store.

Overview

The implementation has 4 parts:

SPM dependency -- add the Sparkle package to the Xcode project
UpdaterManager.swift -- a singleton that wraps
```
SPUStandardUpdaterController
```
Info.plist keys --
```
SUFeedURL
```
and
```
SUPublicEDKey
```
UI integration -- "Check for Updates" button in settings/menu bar

Step 1: Add Sparkle via SPM

In Xcode: File > Add Package Dependencies > enter:

https://github.com/sparkle-project/Sparkle

Use the "Up to Next Major Version" rule with

2.0.0

. Add the

Sparkle

framework to your app target.

Or add it to

Package.swift

if your project uses one:

swift

.package(url: "https://github.com/sparkle-project/Sparkle", from: "2.0.0")

Step 2: Create UpdaterManager.swift

Copy

references/UpdaterManager.swift

into your project. This is a singleton that:

Creates

SPUStandardUpdaterController

early (before

applicationDidFinishLaunching

returns)

Publishes
```
canCheckForUpdates
```
for UI binding
Exposes
```
automaticallyChecksForUpdates
```
toggle
Skips all update logic in DEBUG builds (so you don't get update prompts during development)
For menu-bar-only apps: temporarily switches to
```
.regular
```
activation policy before showing the update window

The key design decisions in this file:

startingUpdater: false
in the initializer, then calling
```
start()
```
explicitly in
```
applicationDidFinishLaunching
```
. This gives you control over timing.
DEBUG guards on
```
start()
```
and
```
checkForUpdates()
```
. Sparkle should never run in debug builds -- it would try to update your debug app with a release build.
ObservableObject
with
@Published
(not
```
@Observable
```
) because we need the Combine
```
publisher(for:)
```
bridge from Sparkle's KVO.

Step 3: Configure Info.plist

Add these keys to your app's

Info.plist

xml

<key>SUFeedURL</key>
<string>https://raw.githubusercontent.com/OWNER/REPO/main/appcast.xml</string>

<key>SUPublicEDKey</key>
<string>YOUR_PUBLIC_EDDSA_KEY_HERE</string>

<key>SUEnableInstallerLauncherService</key>
<true/>

Generating EdDSA Keys

Sparkle uses EdDSA (Ed25519) signing. Generate a keypair:

bash

# Find generate_keys in your DerivedData after building the project with Sparkle
find ~/Library/Developer/Xcode/DerivedData -name "generate_keys" -type f 2>/dev/null | head -1

Run it:

bash

/path/to/generate_keys

This prints the public key and stores the private key in your Keychain. Put the public key in

SUPublicEDKey

in Info.plist. The private key stays in Keychain and is used by

sign_update

during release.

Step 4: Wire Into App

App Delegate

swift

final class AppDelegate: NSObject, NSApplicationDelegate {
    private let updaterManager = UpdaterManager.shared

    func applicationDidFinishLaunching(_ notification: Notification) {
        updaterManager.start()
    }
}

The

UpdaterManager.shared

property must be accessed early so the

SPUStandardUpdaterController

is created before the app finishes launching. Referencing it in the

AppDelegate

property ensures this.

Settings UI (About Pane)

swift

struct AboutSettingsPane: View {
    @ObservedObject private var updaterManager = UpdaterManager.shared

    var body: some View {
        Form {
            Section("Updates") {
                Toggle(isOn: Binding(
                    get: { updaterManager.automaticallyChecksForUpdates },
                    set: { updaterManager.automaticallyChecksForUpdates = $0 }
                )) {
                    Text("Automatically check for updates")
                }

                Button("Check for Updates...") {
                    updaterManager.checkForUpdates()
                }
                .disabled(!updaterManager.canCheckForUpdates)
            }
        }
        .formStyle(.grouped)
        .scrollContentBackground(.hidden)
    }
}

Menu Bar (optional)

swift

Button {
    updaterManager.checkForUpdates()
} label: {
    Label("Check for Updates...", systemImage: "arrow.down.circle")
}
.disabled(!updaterManager.canCheckForUpdates)

Step 5: Create Initial Appcast

Create an

appcast.xml

at the root of your repo. It starts empty and gets populated by your release process:

xml

<?xml version="1.0" encoding="utf-8"?>
<rss version="2.0" xmlns:sparkle="http://www.andymatuschak.org/xml-namespaces/sparkle" xmlns:dc="http://purl.org/dc/elements/1.1/">
  <channel>
    <title>YourApp</title>
    <description>Most recent changes for YourApp.</description>
    <language>en</language>
  </channel>
</rss>

Host this file on GitHub (raw URL) or any static file host. The URL must match

SUFeedURL

in Info.plist.

Menu-Bar-Only Apps

If your app runs as

.accessory

(no Dock icon), Sparkle's update window won't appear unless you temporarily switch to

.regular

. The reference

UpdaterManager

handles this in

checkForUpdates()

swift

func checkForUpdates() {
    NSApp.setActivationPolicy(.regular)
    NSApp.activate(ignoringOtherApps: true)
    controller.checkForUpdates(nil)
}

The app reverts to

.accessory

when the update window closes (handled by your existing activation policy manager).

Hardened Runtime Entitlements

If your app uses Hardened Runtime (required for notarization), no special Sparkle entitlements are needed. Sparkle 2.x works with the standard hardened runtime configuration.

Appcast Item Format

Each release in the appcast looks like this (for reference when building release tooling):

xml

<item>
  <title>Version 1.2 (Build 5)</title>
  <pubDate>Mon, 26 May 2026 12:00:00 +0000</pubDate>
  <sparkle:version>5</sparkle:version>
  <sparkle:shortVersionString>1.2</sparkle:shortVersionString>
  <sparkle:minimumSystemVersion>14.0</sparkle:minimumSystemVersion>
  <description><![CDATA[<ul><li>New feature</li><li>Bug fix</li></ul>]]></description>
  <enclosure url="https://github.com/OWNER/REPO/releases/download/v1.2/YourApp.dmg"
             type="application/octet-stream"
             sparkle:edSignature="BASE64_EDDSA_SIGNATURE"
             length="FILE_SIZE_BYTES" />
</item>

```
sparkle:version
```
=
```
CFBundleVersion
```
(build number)

sparkle:shortVersionString

CFBundleShortVersionString

(marketing version)

sparkle:edSignature

= output of

sign_update YourApp.dmg

```
length
```
= file size in bytes

macos-auto-update

NPX Install

Tags

SKILL.md Content

Sparkle Auto-Update for macOS Apps

Overview

Step 1: Add Sparkle via SPM

Step 2: Create UpdaterManager.swift

Step 3: Configure Info.plist

Generating EdDSA Keys

Step 4: Wire Into App

App Delegate

Settings UI (About Pane)

Menu Bar (optional)

Step 5: Create Initial Appcast

Menu-Bar-Only Apps

Hardened Runtime Entitlements

Appcast Item Format