Technology

Postfold is a native Apple app with no third-party code. Here is what it's built with and why.

A fully native interface for iPhone and iPad, written in Swift 6 with strict concurrency checking.

Your library is stored with SwiftData and synced through the private CloudKit database in your iCloud.

Only Apple frameworks. No analytics, ads or crash-reporting libraries, so nothing ships that we didn't write.

Architecture

App + Share Extension. The Share Extension never opens the database. It reads a small list of your folders and drops each new save into an inbox in a shared App Group container. The main app imports the inbox when it opens. This keeps the extension fast and avoids two processes writing to the same store.
Shared Swift package. Link parsing, oEmbed parsing, models and the sort/filter query live in one local package used by both the app and the extension.
CloudKit-friendly model. Every field has a default and relationships are optional, as CloudKit requires. Duplicates created by offline saves on two devices are merged on launch.

oEmbed only. Post text and embed markup come from X's public oEmbed endpoint, requested with dnt=true and omit_script=true. Responses are parsed without loading HTML into a web view.
Official embed. The details screen renders the oEmbed HTML with X's widgets.js in a WKWebView. Every link tap is handed to iOS, which opens the X app or Safari.
Post dates from IDs. X post IDs encode their creation time, so Postfold can sort by date posted without any extra request.
Polite re-checks. A background refresh task re-checks a small batch of the oldest saves, one request at a time.

The app's privacy manifest declares no tracking, no tracking domains and no collected data.
Clipboard detection asks iOS for a yes/no "is there probably a link?" answer, so no paste prompt appears and nothing is read until you tap Paste.
The only network hosts the app talks to are X's embed services.

iPhone or iPad with iOS 18 or later. Some interface touches use iOS 26 features when available.