diff --git a/Sources/ProcessOut/Sources/Core/Formatters/PhoneNumber/MetadataProvider/DefaultPhoneNumberMetadataProvider.swift b/Sources/ProcessOut/Sources/Core/Formatters/PhoneNumber/MetadataProvider/DefaultPhoneNumberMetadataProvider.swift
index 942a42fdb..4d85408ea 100644
--- a/Sources/ProcessOut/Sources/Core/Formatters/PhoneNumber/MetadataProvider/DefaultPhoneNumberMetadataProvider.swift
+++ b/Sources/ProcessOut/Sources/Core/Formatters/PhoneNumber/MetadataProvider/DefaultPhoneNumberMetadataProvider.swift
@@ -11,36 +11,55 @@ final class DefaultPhoneNumberMetadataProvider: PhoneNumberMetadataProvider {
 
     static let shared = DefaultPhoneNumberMetadataProvider()
 
+    /// - NOTE: Method is asynchronous.
+    func prewarm() {
+        loadMetadata(sync: false)
+    }
+
     // MARK: - PhoneNumberMetadataProvider
 
     func metadata(for countryCode: String) -> PhoneNumberMetadata? {
         let transformedCountryCode = countryCode.applyingTransform(.toLatin, reverse: false) ?? countryCode
-        return metadata[transformedCountryCode]
+        if let metadata = metadata {
+            return metadata[transformedCountryCode]
+        }
+        loadMetadata(sync: true)
+        return metadata?[transformedCountryCode]
     }
 
-    func prewarm() {
-        _ = metadata
-    }
+    // MARK: - Private Properties
+
+    private let dispatchQueue: DispatchQueue
+
+    @UnfairlyLocked
+    private var metadata: [String: PhoneNumberMetadata]?
 
     // MARK: - Private Methods
 
     private init() {
-        // NOP
+        dispatchQueue = DispatchQueue(label: "process-out.phone-number-metadata-provider", qos: .userInitiated)
     }
 
-    // MARK: - Private Properties
-
-    private lazy var metadata: [String: PhoneNumberMetadata] = {
-        let metadata: [PhoneNumberMetadata]
-        do {
-            let data = try Data(contentsOf: Files.phoneNumberMetadata.url)
-            metadata = try JSONDecoder().decode([PhoneNumberMetadata].self, from: data)
-        } catch {
-            return [:]
-        }
-        return Dictionary(grouping: metadata, by: \.countryCode).compactMapValues { values in
-            let countryCode = values.first!.countryCode // swiftlint:disable:this force_unwrapping
-            return PhoneNumberMetadata(countryCode: countryCode, formats: values.flatMap(\.formats))
+    private func loadMetadata(sync: Bool) {
+        let dispatchWorkItem = DispatchWorkItem { [weak self] in
+            guard let self, self.metadata == nil else {
+                return
+            }
+            let groupedMetadata: [String: PhoneNumberMetadata]
+            do {
+                let data = try Data(contentsOf: Files.phoneNumberMetadata.url)
+                let metadata = try JSONDecoder().decode([PhoneNumberMetadata].self, from: data)
+                groupedMetadata = Dictionary(grouping: metadata, by: \.countryCode).compactMapValues { values in
+                    let countryCode = values.first!.countryCode // swiftlint:disable:this force_unwrapping
+                    return PhoneNumberMetadata(countryCode: countryCode, formats: values.flatMap(\.formats))
+                }
+            } catch {
+                assertionFailure("Failed to load metadata: \(error.localizedDescription)")
+                groupedMetadata = [:]
+            }
+            self.$metadata.withLock { $0 = groupedMetadata }
         }
-    }()
+        let executor = sync ? dispatchQueue.sync : dispatchQueue.async
+        executor(dispatchWorkItem)
+    }
 }
diff --git a/Sources/ProcessOut/Sources/Core/Logger/Destinations/SystemLoggerDestination.swift b/Sources/ProcessOut/Sources/Core/Logger/Destinations/SystemLoggerDestination.swift
index 33a2a46f6..f7b5a5179 100644
--- a/Sources/ProcessOut/Sources/Core/Logger/Destinations/SystemLoggerDestination.swift
+++ b/Sources/ProcessOut/Sources/Core/Logger/Destinations/SystemLoggerDestination.swift
@@ -6,7 +6,7 @@
 //
 
 import Foundation
-import os
+@_implementationOnly import os
 
 final class SystemLoggerDestination: LoggerDestination {
 
diff --git a/Sources/ProcessOut/Sources/Core/Utils/UnfairlyLocked.swift b/Sources/ProcessOut/Sources/Core/Utils/UnfairlyLocked.swift
new file mode 100644
index 000000000..9a9409e39
--- /dev/null
+++ b/Sources/ProcessOut/Sources/Core/Utils/UnfairlyLocked.swift
@@ -0,0 +1,63 @@
+//
+//  UnfairlyLocked.swift
+//  ProcessOut
+//
+//  Created by Andrii Vysotskyi on 14.07.2023.
+//
+
+@_implementationOnly import os
+
+/// A thread-safe wrapper around a value.
+@propertyWrapper
+final class UnfairlyLocked<Value> {
+
+    init(wrappedValue: Value) {
+        value = wrappedValue
+    }
+
+    /// The contained value. Unsafe for anything more than direct read or write.
+    var wrappedValue: Value {
+        lock.withLock { value }
+    }
+
+    var projectedValue: UnfairlyLocked<Value> {
+        self
+    }
+
+    func withLock<R>(_ body: (inout Value) -> R) -> R {
+        lock.withLock {
+            body(&value)
+        }
+    }
+
+    // MARK: - Private Properties
+
+    private let lock = UnfairLock()
+    private var value: Value
+}
+
+/// An `os_unfair_lock` wrapper.
+private final class UnfairLock {
+
+    init() {
+        unfairLock = .allocate(capacity: 1)
+        unfairLock.initialize(to: os_unfair_lock())
+    }
+
+    func withLock<R>(_ body: () -> R) -> R {
+        defer {
+            os_unfair_lock_unlock(unfairLock)
+        }
+        os_unfair_lock_lock(unfairLock)
+        return body()
+    }
+
+    deinit {
+        unfairLock.deinitialize(count: 1)
+        unfairLock.deallocate()
+    }
+
+    // MARK: - Private Properties
+
+    private let unfairLock: os_unfair_lock_t
+}