19.3 · Share, Action, keyboards, message filtering, web extensions and network extensions

The extension points differ in who hosts them, what they may see, and what privilege they need. Most interview questions are really “which point fits, and what are its constraints?”

Mental model. Match the extension point to the user’s moment, and respect its privacy and entitlement boundary.

Sharing and acting

Share and Action extensions.

  1. How do Share and Action extensions work, and how do they receive and return data? 19.3.1 · L3
    A Share extension (com.apple.share-services) lets users send content from another app into yours through the share sheet: a link in Safari into your read-later…

System-level points

Keyboards, filters, web extensions, ReplayKit and network extensions at a glance.

  1. What do keyboards, message filtering, call directory, content blockers and web extensions, ReplayKit and network extensions each do, and what constrains them? 19.3.2 · L3
    Beyond sharing, iOS has extension points that plug your code into system features. Each has a narrow job, a privacy boundary and often an entitlement. Custom…

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