tzf-swift: a fast timezone finder for Swift

Note

This package use a simplified polygon data and not so accurate around borders.

Usage

Add the dependency to your Package.swift file:

dependencies: [
    .package(url: "https://github.com/ringsaturn/tzf-swift.git", from: "{latest_version}")
]

Then add something like this:

import Foundation
import tzf

do {
    let finder = try DefaultFinder()

    // Test for Beijing
    let timezone = try finder.getTimezone(lng: 116.3833, lat: 39.9167)
    print("Beijing timezone:", timezone)

    // Test for a location with multiple possible timezones
    let timezones = try finder.getTimezones(lng: 87.5703, lat: 43.8146)
    print("Multiple possible timezones:", timezones)

    // Get data version
    print("Data version:", finder.dataVersion())

} catch {
    print("Error:", error)
}

Output:

Build of product 'demo' complete! (0.15s)
Beijing timezone: Asia/Shanghai
Multiple possible timezones: ["Asia/Shanghai", "Asia/Urumqi"]
Data version: 2025a/2025a

Performance

Just like tzf packages in Go/Rust/Python, the Swift version is also fast, and designed for server-side high-performance use cases.

Hardware: MacBook Pro with Apple M3 Max.

Processing 1 million queries took 4500ms. Benchmark Summary:

Implementation	Test Scale	Execution Time (ms)	Success Rate	Operations per Second (op/sec)	Memory Usage (Peak MB)	Instructions (G)
TZF.DefaultFinder	1,000,000	4,717	100%	~212,000	129	73
TZF.Finder	1,000,000	19,000	100%	~52,632	115	324
TZF.PreindexFinder	1,000,000	1,548	~85%	~646,000	129	23
SwiftTimeZoneLookup.lookup	10,000	3,077	100%	~3,250	105	42
SwiftTimeZoneLookup.simple	10,000	3,209	100%	~3,116	104	45

Full benchmark results can be viewed in benchmark_baseline.txt.

Related Projects

Language or Sever	Link	Note
Go	ringsaturn/tzf
Ruby	HarlemSquirrel/tzf-rb	build with tzf-rs
Rust	ringsaturn/tzf-rs
Swift	ringsaturn/tzf-swift
Python	ringsaturn/tzfpy	build with tzf-rs
HTTP API	ringsaturn/tzf-server	build with tzf
HTTP API	racemap/rust-tz-service	build with tzf-rs
Redis Server	ringsaturn/tzf-server	build with tzf
Redis Server	ringsaturn/redizone	build with tzf-rs
JS via Wasm(browser only)	ringsaturn/tzf-wasm	build with tzf-rs
Online	ringsaturn/tzf-web	build with tzf-wasm

License

This project is licensed under the MIT License. See the LICENSE file for details.

The data is licensed under ODbL-1.0 license, which compiled from https://github.com/evansiroky/timezone-boundary-builder