Platforms CocoaPods compatible Carthage compatible SPM compatible Swift version Swift version Swift version

Modern Swift API for FirebaseRemoteConfig

SwiftyRemoteConfig makes Firebase Remote Config enjoyable to use by combining expressive Swifty API with the benefits fo static typing. This library is strongly inspired by SwiftyUserDefaults.

HEADS UP ! You need workaround to use with Xcode 13.3 or later

Because of Xcode compiler bug, you need workaround to use this library with Xcode 13.3 or later. Followings are recommended steps for workaround.

  1. Create SwiftyRemoteConfig+Workaround.swift file in module which is using SwiftyRemoteConfig.
  2. Copy the codes below into SwiftyRemoteConfig+Workaround.swift. This is pretty much a copy from the BuiltIns.swift file in the Sources folder: https://raw.githubusercontent.com/fumito-ito/SwiftyRemoteConfig/master/Sources/SwiftyRemoteConfig/BuiltIns.swift
import Foundation
import SwiftyRemoteConfig

extension RemoteConfigSerializable {
    public static var _remoteConfigArray: RemoteConfigArrayBridge<[T]> { RemoteConfigArrayBridge() }

extension Date: RemoteConfigSerializable {
    public static var _remoteConfig: RemoteConfigObjectBridge<Date> { RemoteConfigObjectBridge() }

extension String: RemoteConfigSerializable {
    public static var _remoteConfig: RemoteConfigStringBridge { RemoteConfigStringBridge() }

extension Int: RemoteConfigSerializable {
    public static var _remoteConfig: RemoteConfigIntBridge { RemoteConfigIntBridge() }

extension Double: RemoteConfigSerializable {
    public static var _remoteConfig: RemoteConfigDoubleBridge { return RemoteConfigDoubleBridge() }

extension Bool: RemoteConfigSerializable {
    public static var _remoteConfig: RemoteConfigBoolBridge { RemoteConfigBoolBridge() }

extension Data: RemoteConfigSerializable {
    public static var _remoteConfig: RemoteConfigDataBridge { RemoteConfigDataBridge() }

extension URL: RemoteConfigSerializable {
    public static var _remoteConfig: RemoteConfigUrlBridge { RemoteConfigUrlBridge() }
    public static var _remoteConfigArray: RemoteConfigCodableBridge<[URL]> { RemoteConfigCodableBridge() }

extension RemoteConfigSerializable where Self: Codable {
    public static var _remoteConfig: RemoteConfigCodableBridge<Self> { RemoteConfigCodableBridge() }
    public static var _remoteConfigArray: RemoteConfigCodableBridge<[Self]> { RemoteConfigCodableBridge() }

extension RemoteConfigSerializable where Self: RawRepresentable {
    public static var _remoteConfig: RemoteConfigRawRepresentableBridge<Self> { RemoteConfigRawRepresentableBridge() }
    public static var _remoteConfigArray: RemoteConfigRawRepresentableArrayBridge<[Self]> { RemoteConfigRawRepresentableArrayBridge() }

extension RemoteConfigSerializable where Self: NSCoding {
    public static var _remoteConfig: RemoteConfigKeyedArchiverBridge<Self> { RemoteConfigKeyedArchiverBridge() }
    public static var _remoteConfigArray: RemoteConfigKeyedArchiverArrayBridge<[Self]> { RemoteConfigKeyedArchiverArrayBridge() }

extension Dictionary: RemoteConfigSerializable where Key == String {
    public typealias T = [Key: Value]
    public typealias Bridge = RemoteConfigObjectBridge<T>
    public typealias ArrayBridge = RemoteConfigArrayBridge<[T]>

    public static var _remoteConfig: Bridge { Bridge() }
    public static var _remoteConfigArray: ArrayBridge { ArrayBridge() }

extension Array: RemoteConfigSerializable where Element: RemoteConfigSerializable {
    public typealias T = [Element.T]
    public typealias Bridge = Element.ArrayBridge
    public typealias ArrayBridge = RemoteConfigObjectBridge<[T]>

    public static var _remoteConfig: Bridge { Element._remoteConfigArray }
    public static var _remoteConfigArray: ArrayBridge {
        fatalError("Multidimensional arrays are not supported yet")

extension Optional: RemoteConfigSerializable where Wrapped: RemoteConfigSerializable {
    public typealias Bridge = RemoteConfigOptionalBridge<Wrapped.Bridge>
    public typealias ArrayBridge = RemoteConfigOptionalBridge<Wrapped.ArrayBridge>

    public static var _remoteConfig: Bridge { RemoteConfigOptionalBridge(bridge: Wrapped._remoteConfig) }
    public static var _remoteConfigArray: ArrayBridge { RemoteConfigOptionalBridge(bridge: Wrapped._remoteConfigArray) }


There is only one step to start using SwiftyRemoteConfig.

Define your Keys !

extension RemoteConfigKeys {
    var recommendedAppVersion: RemoteConfigKey<String?> { .init("recommendedAppVersion")}
    var isEnableExtendedFeature: RemoteConfigKey<Bool> { .init("isEnableExtendedFeature", defaultValue: false) }

... and just use it !

// get remote config value easily
let recommendedVersion = RemoteConfigs[.recommendedAppVersion]

// eality work with custom deserialized types
let themaColor: UIColor = RemoteConfigs[.themaColor]

If you use Swift 5.1 or later, you can also use keyPath dynamicMemberLookup:

let subColor: UIColor = RemoteConfigs.subColor


Define your keys

To get the most out of SwiftyRemoteConfig, define your remote config keys ahead of time:

let flag = RemoteConfigKey<Bool>("flag", defaultValue: false)

Just create a RemoteConfigKey object. If you want to have a non-optional value, just provide a defaultValue in the key (look at the example above).

You can now use RemoteConfig shortcut to access those values:

RemoteConfigs[key: flag] // => false, type as "Bool"

The compiler won't let you fetching conveniently returns Bool.

Take shortcuts

For extra convenience, define your keys by extending magic RemoteConfigKeys class and adding static properties:

extension RemoteConfigKeys {
    var flag: RemoteConfigKey<Bool> { .init("flag", defaultValue: false) }
    var userSectionName: RemoteConfigKey<String?> { .init("default") }

and use the shortcut dot syntax:

RemoteConfigs[\.flag] // => false

Supported types

SwiftyRemoteConfig supports standard types as following:

Single value Array
String [String]
Int [Int]
Double [Double]
Bool [Bool]
Data [Data]
Date [Date]
[String: Any] [[String: Any]]

and that's not all !

Extending existing types


SwiftyRemoteConfig supports Codable ! Just conform to RemoteConfigSerializable in your type:

final class UserSection: Codable, RemoteConfigSerializable {
    let name: String

No implementation needed ! By doing this you will get an option to specify an optional RemoteConfigKey:

let userSection = RemoteConfigKey<UserSection?>("userSection")

Additionally, you've get an array support for free:

let userSections = RemoteConfigKey<[UserSection]?>("userSections")


Support your custom NSCoding type the same way as with Codable support:

final class UserSection: NSObject, NSCoding, RemoteConfigSerializable {


And the last, RawRepresentable support ! Again, the same situation like with Codable and NSCoding:

enum UserSection: String, RemoteConfigSerializable {
    case Basic
    case Royal

Custom types

If you want to add your own custom type that we don't support yet, we've got you covered. We use RemoteConfigBridge s of many kinds to specify how you get values and arrays of values. When you look at RemoteConfigSerializable protocol, it expects two properties in each type: _remoteConfig and _remoteConfigArray, where both are of type RemoteConfigBridge.

For instance, this is a bridge for single value data retrieving using NSKeyedUnarchiver:

public struct RemoteConfigKeyedArchiveBridge<T>: RemoteConfigBridge {

    public func get(key: String, remoteConfig: RemoteConfig) -> T? {
        remoteConfig.data(forKey: key).flatMap(NSKeyedUnarchiver.unarchiveObject) as? T

    public func deserialize(_ object: RemoteConfigValue) -> T? {
        guard let data = object as? Data else {
            return nil

        NSKeyedUnarchiver.unarchiveObject(with: data)

Bridge for default retrieving array values:

public struct RemoteConfigArrayBridge<T: Collection>: RemoteConfigBridge {
    public func get(key: String, remoteConfig: RemoteConfig) -> T? {
        remoteConfig.array(forKey: key) as? T

    public func deserialize(_ object: RemoteConfigValue) -> T? {
        return nil

Now, to use these bridges in your type you simply declare it as follows:

struct CustomSerializable: RemoteConfigSerializable {
    static var _remoteConfig: RemoteConfigBridge<CustomSerializable> { RemoteConfigKeyedArchiverBridge() }
    static var _remoteConfigArray: RemoteConfigBridge<[CustomSerializable]> { RemoteConfigKeyedArchiverBridge() }

    let key: String

Unfortunately, if you find yourself in a situation where you need a custom bridge, you'll probably need to write your own:

final class RemoteConfigCustomBridge: RemoteConfigBridge {
    func get(key: String, remoteConfig: RemoteConfig) -> RemoteConfigCustomSerializable? {
        let value = remoteConfig.string(forKey: key)
        return value.map(RemoteConfigCustomSerializable.init)

    func deserialize(_ object: Any) -> RemoteConfigCustomSerializable? {
        guard let value = object as? String {
            return nil

        return RemoteConfigCustomSerializable(value: value)

final class RemoteConfigCustomArrayBridge: RemoteConfigBridge {
    func get(key: String, remoteConfig: RemoteConfig) -> [RemoteConfigCustomSerializable]? {
        remoteConfig.array(forKey: key)?
            .compactMap({ $0 as? String })

    func deserialize(_ object: Any) -> [RemoteConfigCustomSerializable]? {
        guard let values as? [String] else {
            return nil

        return values.map({ RemoteConfigCustomSerializable.init })

struct RemoteConfigCustomSerializable: RemoteConfigSerializable, Equatable {
    static var _remoteConfig: RemoteConfigCustomBridge { RemoteConfigCustomBridge() }
    static var _remoteConfigArrray: RemoteConfigCustomArrayBridge: { RemoteConfigCustomArrayBridge() }

    let value: String

To support existing types with different bridges, you can extend it similarly:

extension Data: RemoteConfigSerializable {
    public static var _remoteConfigArray: RemoteConfigArrayBridge<[T]> { RemoteConfigArrayBridge() }
    public static var _remoteConfig: RemoteConfigBridge<T> { RemoteConfigBridge() }

Also, take a look at our source code or tests to see more examples of bridges. If you find yourself confused with all these bridges, please create an issue and we will figure something out.

Property Wrappers

SwiftyRemoteConfig provides property wrappers for Swift 5.1! The property wrapper, @SwiftyRemoteConfig, provides an option to use it with key path.

Note: This property wrappers only read support. You can set new value to the property, but any changes will NOT be reflected to remote config value


Given keys:

extension RemoteConfigKeys {
    var userColorScheme: RemoteConfigKey<String> { .init("userColorScheme", defaultValue: "default") }

You can declare a Settings struct:

struct Settings {
    @SwiftyRemoteConfig(keyPath: \.userColorScheme)
    var userColorScheme: String

You can also check property details with projected value:

struct Settings {
    @SwiftyRemoteConfig(keyPath: \.newFeatureAvailable)
    var newFeatureAvailable: String

struct NewFeatureRouter {
    func show(with settings: Settings) {
        if settings.$newFeatureAvailable.lastFetchTime != nil {
            // show new feature
        } else {
            // fetch and activate remote config before routing

KeyPath dynamicMemberLookup

SwiftyRemoteConfig makes KeyPath dynamicMemberLookup usable in Swift 5.1.

extension RemoteConfigKeys {
    var recommendedAppVersion: RemoteConfigKey<String?> { .init("recommendedAppVersion")}
    var themaColor: RemoteConfigKey<UIColor> { .init("themaColor", defaultValue: .white) }

and just use it ;-)

// get remote config value easily
let recommendedVersion = RemoteConfig.recommendedAppVersion

// eality work with custom deserialized types
let themaColor: UIColor = RemoteConfig.themaColor


SwiftyRemoteConfig provides values from RemoteConfig with Combine's stream.

extension RemoteConfigKeys {
    var contentText: RemoteConfigKey<String> { .init("content_text", defaultValue: "Hello, World!!") }

and get a RemoteConfig's value from Combine stream !

import FirebaseRemoteConfig
import SwiftyRemoteConfig
import Combine

final class ViewModel: ObservableObject {
    @Published var contentText: String

    private var cancellables: Set<AnyCancellable> = []

    init() {
        contentText = RemoteConfigs.contentText

            .fetchedPublisher(for: \.contentText)
            .receive(on: RunLoop.main)
            .assign(to: \.contentText, on: self)
            .store(in: &cancellables)


  • Swift version >= 5.0


  • iOS version >= 11.0
  • macOS version >= 10.12
  • tvOS version >= 12.0
  • watchOS version >= 6.0


  • Firebase iOS SDK >= 10.0.0



If you're using Cocoapods, just add this line to your Podfile:

pod 'SwiftyRemoteConfig`, `~> 1.0.0`

Install by running this command in your terminal:

$ pod install

Then import the library in all files where you use it:

import SwiftyRemoteConfig


Just add your Cartfile

github "fumito-ito/SwiftyRemoteConfig" ~> 1.0.0

Swift Package Manager

Just add to your Package.swift under dependencies

let package = Package(
    name: "MyPackage",
    products: [...],
    dependencies: [
        .package(url: "https://github.com/fumito-ito/SwiftyRemoteConfig.git", .upToNextMajor(from: "1.0.0"))

SwiftyRemoteConfig is available under the Apache License 2.0. See the LICENSE file for more detail.