diff --git a/Sources/ATProtoKit/Utilities/APIClientService.swift b/Sources/ATProtoKit/Utilities/APIClientService.swift
index 9bb0d6ec83..7f28b9f63b 100644
--- a/Sources/ATProtoKit/Utilities/APIClientService.swift
+++ b/Sources/ATProtoKit/Utilities/APIClientService.swift
@@ -19,17 +19,74 @@ public actor APIClientService {
 
     /// The `URLSession` instance to be used for network requests.
     private(set) var urlSession: URLSession
+    
+    /// The `UserAgent` instance to identify all network requests originating from the `ATProtoKit` sdk
+    public static let userAgent: String = {
+        let info = Bundle.main.infoDictionary
+        let executable = (info?["CFBundleExecutable"] as? String) ??
+            (ProcessInfo.processInfo.arguments.first?.split(separator: "/").last.map(String.init)) ??
+            "Unknown"
+        let bundle = info?["CFBundleIdentifier"] as? String ?? "Unknown"
+        let appVersion = info?["CFBundleShortVersionString"] as? String ?? "Unknown"
+        let appBuild = info?["CFBundleVersion"] as? String ?? "Unknown"
+
+        let osNameVersion: String = {
+            let version = ProcessInfo.processInfo.operatingSystemVersion
+            let versionString = "\(version.majorVersion).\(version.minorVersion).\(version.patchVersion)"
+            let osName: String = {
+                #if os(iOS)
+                #if targetEnvironment(macCatalyst)
+                return "macOS(Catalyst)"
+                #else
+                return "iOS"
+                #endif
+                #elseif os(watchOS)
+                return "watchOS"
+                #elseif os(tvOS)
+                return "tvOS"
+                #elseif os(macOS)
+                #if targetEnvironment(macCatalyst)
+                return "macOS(Catalyst)"
+                #else
+                return "macOS"
+                #endif
+                #elseif swift(>=5.9.2) && os(visionOS)
+                return "visionOS"
+                #elseif os(Linux)
+                return "Linux"
+                #elseif os(Windows)
+                return "Windows"
+                #elseif os(Android)
+                return "Android"
+                #else
+                return "Unknown"
+                #endif
+            }()
+
+            return "\(osName) \(versionString)"
+        }()
+
+        /// This needs to be updated manually or read from a central location
+        ///  To get truly accurate version would need to read from Package.resolved and I haven't found a way to do so
+        let atProtoVersion = "ATProtoKit/0.21.0"
+
+        let userAgent = "\(executable)/\(appVersion) (\(bundle); build:\(appBuild); \(osNameVersion)) \(atProtoVersion)"
+
+        return userAgent
+    }()
 
     /// A `URLSession` object for use in all HTTP requests.
     public static let shared = APIClientService()
 
     /// Creates an instance for use in accepting and returning API requests and
     /// responses respectively.
-    /// 
+    ///
     /// - Parameter configuration: An instance of `URLSessionConfiguration`.
     /// Defaults to `.default`.
     private init() {
-        self.urlSession = URLSession(configuration: .default)
+        let sessionConfig = URLSessionConfiguration.default
+        sessionConfig.httpAdditionalHeaders = ["User-Agent": APIClientService.userAgent]
+        self.urlSession = URLSession(configuration: sessionConfig)
     }
 
     /// Configures the singleton instance with a custom `URLSessionConfiguration`.