# What is an Apple Developer ID?

> A Developer ID is the certificate Apple gives developers to sign Mac apps shared outside the App Store. Learn what it proves and what it does not.

Canonical: https://www.notchstar.com/glossary/developer-id/
Last updated: 2026-11-04

Published 2026-11-04.

A Developer ID is a certificate from Apple that a developer uses to sign a Mac app that is distributed outside the Mac App Store. Apple names two kinds: Developer ID Application for apps, and Developer ID Installer for installer packages.

## What it proves

The signature tells macOS who made the app and that it has not been altered since signing. Apple says that signing with a Developer ID, together with a [notarization](https://www.notchstar.com/glossary/notarization/) ticket, lets [Gatekeeper](https://www.notchstar.com/glossary/gatekeeper/) verify that the software is not known malware and has not been tampered with.

## What it does not prove

A signature says who signed it, not that the app is good. It does not say what the app does with your data. For that you need the developer's privacy statement and, if you want, a network monitor.

## Why it matters

Without a Developer ID, an app can only be signed ad hoc, and macOS cannot tie it to a developer. NotchStar 1.0.0 to 1.0.2 were signed ad hoc. Since version 1.0.3, on 9 October 2026, downloads are signed with a Developer ID.

## Related

Check the signature yourself with `codesign -dv --verbose=2 /Applications/NotchStar.app`, or read [is NotchStar safe](https://www.notchstar.com/guides/is-notchstar-safe/). Developers should also read about the [hardened runtime](https://www.notchstar.com/glossary/hardened-runtime/).

## Keep reading.

- [What is notarization on Mac?](https://www.notchstar.com/glossary/notarization/): Notarization is Apple's automated check of Mac software before you download it. Learn what Apple says it covers and what it does not.
- [What is Gatekeeper on a Mac?](https://www.notchstar.com/glossary/gatekeeper/): Gatekeeper is the macOS check that decides whether downloaded software may run. Learn what it checks, why it shows warnings and how it relates to notarization.
- [What is the hardened runtime?](https://www.notchstar.com/glossary/hardened-runtime/): The hardened runtime is a code signing setting that limits what a Mac app can do. Learn what it blocks and how entitlements relax it.
- [Is NotchStar safe? Signing, permissions and what it sends](https://www.notchstar.com/guides/is-notchstar-safe/): NotchStar is signed and notarized by Apple, needs no account and sends nothing unless you opt in. See every permission it asks for and how to check it yourself.

## More in Security and signing.

- [What is Gatekeeper on a Mac?](https://www.notchstar.com/glossary/gatekeeper/): Gatekeeper is the macOS check that decides whether downloaded software may run. Learn what it checks, why it shows warnings and how it relates to notarization.
- [What is notarization on Mac?](https://www.notchstar.com/glossary/notarization/): Notarization is Apple's automated check of Mac software before you download it. Learn what Apple says it covers and what it does not.
- [What is a DMG file?](https://www.notchstar.com/glossary/dmg/): A DMG is a disk image, a single file that opens like a drive. Learn how apps ship in one, how to install from it and how to verify the download.
- [What is the hardened runtime?](https://www.notchstar.com/glossary/hardened-runtime/): The hardened runtime is a code signing setting that limits what a Mac app can do. Learn what it blocks and how entitlements relax it.
- [What are entitlements in macOS?](https://www.notchstar.com/glossary/entitlements/): Entitlements are key value pairs signed into a Mac app that grant it permission to use a service or technology. Learn what NotchStar asks for and why.
- [What is the App Sandbox on Mac?](https://www.notchstar.com/glossary/app-sandbox/): The App Sandbox is a macOS feature that limits an app's access to system resources and user data. Learn how it differs from the hardened runtime.