Kronos is an NTP client library written in Swift. It supports sub-seconds precision and provides a stable monotonic clock that won't be affected by changes in the clock. ## Example app [This](https://github.com/MobileNativeFoundation/Kronos/blob/master/Example/main.swift) is an example app that displays the monotonic `Clock.now` on the left and the system clock (initially out of date) on the right.  ## Usage ### Sync clock using a pool of NTP servers Calling `Clock.sync` will fire a bunch of NTP requests to up to 5 of the servers on the given NTP pool (default is `time.apple.com`). As soon as we get the first response, the given closure is called but the `Clock` will keep trying to get a more accurate response. ```swift Clock.sync { date, offset in // This is the first sync (note that this is the fastest but not the // most accurate run print(date) } ``` ### Get an NTP sync'ed date `Clock.now` is a monotonic NSDate that won't be affected by clock changes. ```swift NSTimer.scheduledTimerWithTimeInterval(1.0, target: self, selector: #selector(Example.tick), userInfo: nil, repeats: true) @objc func tick() { print(Clock.now) // Note that this clock will get more accurate as // more NTP servers respond. } ``` ## Installation ### [CocoaPods](http://cocoapods.org) Add Kronos to your `Podfile`: ```ruby pod 'Kronos' ``` ### Swift Package Manager Add Kronos to your `Package.swift`: ```bash .package(name: "Kronos", url: "https://github.com/MobileNativeFoundation/Kronos.git", .upToNextMajor(from: "TAG")), ``` ### Bazel Add Kronos to your `WORKSPACE`: ```bzl http_archive( name = "Kronos", sha256 = "", strip_prefix = "Kronos-TAG/", url = "https://github.com/MobileNativeFoundation/Kronos/archive/TAG.tar.gz", ) ``` Then depend on `@Kronos//:Kronos` ### Android Check out [Kronos for Android](https://github.com/lyft/Kronos-Android)