diff --git a/.gitignore b/.gitignore
index 62a44966..752eeee0 100644
--- a/.gitignore
+++ b/.gitignore
@@ -21,6 +21,8 @@ __LOCAL_LLMs/models/
 __LOCAL_LLMs/.venv-*/
 __LOCAL_LLMs/*.wav
 packages/swift-platform-sdk/build/
+packages/swift-platform-sdk/.build/
+packages/swift-platform-sdk/.swiftpm/
 packages/kotlin-platform-sdk/build/
 packages/kotlin-platform-sdk/.gradle/
 packages/kotlin-platform-sdk/gradle/
diff --git a/packages/swift-platform-sdk/Sources/ByteLystPlatform.swift b/packages/swift-platform-sdk/Sources/ByteLystPlatform.swift
new file mode 100644
index 00000000..0d0343c0
--- /dev/null
+++ b/packages/swift-platform-sdk/Sources/ByteLystPlatform.swift
@@ -0,0 +1,121 @@
+// ── ByteLystPlatform ────────────────────────────────────────
+// Unified entry point for the ByteLyst platform SDK.
+// Creates and wires all platform services from a single config.
+//
+// Usage:
+//   let platform = ByteLystPlatform(config: .init(
+//       productId: "peakpulse",
+//       baseURL: "https://api.peakpulse.app",
+//       bundleId: "com.saravana.peakpulse"
+//   ))
+//
+//   platform.start()                          // Start telemetry + flags + kill switch
+//   platform.telemetry.trackScreen("home")    // Track events
+//   let isNew = platform.flags.isEnabled("new_feature")
+//   platform.stop()                           // Flush + stop timers
+
+import Foundation
+
+/// Unified entry point that wires all ByteLyst platform services together.
+/// Create one instance at app launch and access services via properties.
+public final class ByteLystPlatform {
+
+    /// Platform configuration.
+    public let config: BLPlatformConfig
+
+    /// HTTP client shared by all services.
+    public let client: BLPlatformClient
+
+    /// Telemetry event tracking.
+    public let telemetry: BLTelemetryClient
+
+    /// Feature flag polling.
+    public let flags: BLFeatureFlagClient
+
+    /// Kill switch checker.
+    public let killSwitch: BLKillSwitchClient
+
+    /// Crash reporter (MetricKit).
+    public let crashReporter: BLCrashReporter
+
+    /// Keychain access (via bundleId as service).
+    public let keychain: BLKeychainAccessor
+
+    /// Audit logger.
+    public let auditLog: BLAuditLogger
+
+    /// Auth client.
+    public let auth: BLAuthClient
+
+    /// Whether `start()` has been called.
+    public private(set) var isStarted = false
+
+    public init(config: BLPlatformConfig) {
+        self.config = config
+        self.client = BLPlatformClient(config: config)
+        self.telemetry = BLTelemetryClient(config: config, client: client)
+        self.flags = BLFeatureFlagClient(config: config, client: client)
+        self.killSwitch = BLKillSwitchClient(config: config)
+        self.crashReporter = BLCrashReporter(productId: config.productId)
+        self.keychain = BLKeychainAccessor(service: config.bundleId)
+        self.auditLog = BLAuditLogger(productId: config.productId)
+        self.auth = BLAuthClient(config: config, client: client)
+    }
+
+    /// Test-only initializer that accepts a custom URLSessionConfiguration.
+    public init(config: BLPlatformConfig, sessionConfiguration: URLSessionConfiguration) {
+        self.config = config
+        self.client = BLPlatformClient(config: config, sessionConfiguration: sessionConfiguration)
+        self.telemetry = BLTelemetryClient(config: config, client: client)
+        self.flags = BLFeatureFlagClient(config: config, client: client)
+        self.killSwitch = BLKillSwitchClient(config: config)
+        self.crashReporter = BLCrashReporter(productId: config.productId)
+        self.keychain = BLKeychainAccessor(service: config.bundleId)
+        self.auditLog = BLAuditLogger(productId: config.productId)
+        self.auth = BLAuthClient(config: config, client: client)
+    }
+
+    // MARK: - Lifecycle
+
+    /// Start all services: telemetry flush timer, feature flag polling, kill switch check.
+    public func start(userId: String? = nil) {
+        guard !isStarted else { return }
+        isStarted = true
+        telemetry.start()
+        flags.start(userId: userId)
+        Task { await killSwitch.check() }
+    }
+
+    /// Stop all services: flush telemetry, stop flag polling.
+    public func stop() {
+        guard isStarted else { return }
+        isStarted = false
+        telemetry.stop()
+        flags.stop()
+    }
+}
+
+// MARK: - Keychain Accessor
+
+/// Convenience wrapper around BLKeychain that binds to a specific service (bundleId).
+public struct BLKeychainAccessor {
+    private let service: String
+
+    public init(service: String) {
+        self.service = service
+    }
+
+    @discardableResult
+    public func save(key: String, value: String) -> Bool {
+        BLKeychain.save(service: service, key: key, value: value)
+    }
+
+    public func read(key: String) -> String? {
+        BLKeychain.read(service: service, key: key)
+    }
+
+    @discardableResult
+    public func delete(key: String) -> Bool {
+        BLKeychain.delete(service: service, key: key)
+    }
+}
diff --git a/packages/swift-platform-sdk/Tests/BLFeatureFlagClientTests.swift b/packages/swift-platform-sdk/Tests/BLFeatureFlagClientTests.swift
new file mode 100644
index 00000000..4f63401a
--- /dev/null
+++ b/packages/swift-platform-sdk/Tests/BLFeatureFlagClientTests.swift
@@ -0,0 +1,31 @@
+import XCTest
+@testable import ByteLystPlatformSDK
+
+final class BLFeatureFlagClientTests: XCTestCase {
+
+    private func makeClient() -> BLFeatureFlagClient {
+        let config = BLPlatformConfig(
+            productId: "testapp",
+            baseURL: "http://localhost:4003",
+            bundleId: "com.bytelyst.test"
+        )
+        let platformClient = BLPlatformClient(config: config)
+        return BLFeatureFlagClient(config: config, client: platformClient)
+    }
+
+    func testDefaultFlagsEmpty() {
+        let client = makeClient()
+        XCTAssertEqual(client.allFlags().count, 0)
+    }
+
+    func testIsEnabledReturnsFalseForUnknownKey() {
+        let client = makeClient()
+        XCTAssertFalse(client.isEnabled("nonexistent_flag"))
+    }
+
+    func testStopDoesNotCrash() {
+        let client = makeClient()
+        client.stop()
+        client.stop() // Double stop
+    }
+}
diff --git a/packages/swift-platform-sdk/Tests/BLKillSwitchClientTests.swift b/packages/swift-platform-sdk/Tests/BLKillSwitchClientTests.swift
new file mode 100644
index 00000000..e018b0c2
--- /dev/null
+++ b/packages/swift-platform-sdk/Tests/BLKillSwitchClientTests.swift
@@ -0,0 +1,27 @@
+import XCTest
+@testable import ByteLystPlatformSDK
+
+final class BLKillSwitchClientTests: XCTestCase {
+
+    private func makeConfig() -> BLPlatformConfig {
+        BLPlatformConfig(
+            productId: "testapp",
+            baseURL: "http://localhost:4003",
+            bundleId: "com.bytelyst.test"
+        )
+    }
+
+    func testDefaultState() {
+        let client = BLKillSwitchClient(config: makeConfig())
+        XCTAssertFalse(client.isDisabled)
+        XCTAssertEqual(client.maintenanceMessage, "")
+    }
+
+    func testReset() {
+        let client = BLKillSwitchClient(config: makeConfig())
+        // Manually test reset clears any hypothetical state
+        client.reset()
+        XCTAssertFalse(client.isDisabled)
+        XCTAssertEqual(client.maintenanceMessage, "")
+    }
+}
diff --git a/packages/swift-platform-sdk/Tests/BLPlatformConfigTests.swift b/packages/swift-platform-sdk/Tests/BLPlatformConfigTests.swift
new file mode 100644
index 00000000..f199d7c4
--- /dev/null
+++ b/packages/swift-platform-sdk/Tests/BLPlatformConfigTests.swift
@@ -0,0 +1,34 @@
+import XCTest
+@testable import ByteLystPlatformSDK
+
+final class BLPlatformConfigTests: XCTestCase {
+
+    func testInitWithDefaults() {
+        let config = BLPlatformConfig(
+            productId: "testapp",
+            baseURL: "http://localhost:4003",
+            bundleId: "com.bytelyst.testapp"
+        )
+        XCTAssertEqual(config.productId, "testapp")
+        XCTAssertEqual(config.baseURL, "http://localhost:4003")
+        XCTAssertEqual(config.platform, "ios")
+        XCTAssertEqual(config.channel, "native")
+        XCTAssertEqual(config.bundleId, "com.bytelyst.testapp")
+        XCTAssertNil(config.appGroupId)
+    }
+
+    func testInitWithCustomValues() {
+        let config = BLPlatformConfig(
+            productId: "peakpulse",
+            baseURL: "https://api.peakpulse.app",
+            platform: "watchos",
+            channel: "companion",
+            bundleId: "com.saravana.peakpulse",
+            appGroupId: "group.com.saravana.peakpulse"
+        )
+        XCTAssertEqual(config.productId, "peakpulse")
+        XCTAssertEqual(config.platform, "watchos")
+        XCTAssertEqual(config.channel, "companion")
+        XCTAssertEqual(config.appGroupId, "group.com.saravana.peakpulse")
+    }
+}
diff --git a/packages/swift-platform-sdk/Tests/BLTelemetryClientTests.swift b/packages/swift-platform-sdk/Tests/BLTelemetryClientTests.swift
new file mode 100644
index 00000000..dc2d534a
--- /dev/null
+++ b/packages/swift-platform-sdk/Tests/BLTelemetryClientTests.swift
@@ -0,0 +1,65 @@
+import XCTest
+@testable import ByteLystPlatformSDK
+
+final class BLTelemetryClientTests: XCTestCase {
+
+    private func makeClient() -> BLTelemetryClient {
+        let config = BLPlatformConfig(
+            productId: "testapp",
+            baseURL: "http://localhost:4003",
+            bundleId: "com.bytelyst.test"
+        )
+        let platformClient = BLPlatformClient(config: config)
+        return BLTelemetryClient(config: config, client: platformClient)
+    }
+
+    func testInstallIdIsStable() {
+        let client = makeClient()
+        let id1 = client.getInstallId()
+        let id2 = client.getInstallId()
+        XCTAssertEqual(id1, id2)
+        XCTAssertFalse(id1.isEmpty)
+    }
+
+    func testSessionIdIsNotEmpty() {
+        let client = makeClient()
+        XCTAssertFalse(client.getSessionId().isEmpty)
+    }
+
+    func testStartGeneratesNewSessionId() {
+        let client = makeClient()
+        let sessionBefore = client.getSessionId()
+        client.start()
+        let sessionAfter = client.getSessionId()
+        // start() rotates session ID
+        XCTAssertNotEqual(sessionBefore, sessionAfter)
+        client.stop()
+    }
+
+    func testStopDoesNotCrash() {
+        let client = makeClient()
+        client.stop() // Stop without start
+        client.start()
+        client.stop()
+        client.stop() // Double stop
+    }
+
+    func testTrackEventDoesNotCrash() {
+        let client = makeClient()
+        client.trackEvent("info", module: "test", name: "unit_test")
+        client.trackEvent("error", module: "test", name: "fail", message: "test error")
+        client.trackEvent("info", module: "test", name: "tagged", tags: ["key": "value"])
+        client.trackEvent("info", module: "test", name: "measured", metrics: ["duration": 1.5])
+    }
+
+    func testTrackScreenDoesNotCrash() {
+        let client = makeClient()
+        client.trackScreen("home")
+        client.trackScreen("settings")
+    }
+
+    func testFlushDoesNotCrashWhenEmpty() {
+        let client = makeClient()
+        client.flush() // Empty queue
+    }
+}
diff --git a/packages/swift-platform-sdk/Tests/ByteLystPlatformTests.swift b/packages/swift-platform-sdk/Tests/ByteLystPlatformTests.swift
new file mode 100644
index 00000000..065c6fd7
--- /dev/null
+++ b/packages/swift-platform-sdk/Tests/ByteLystPlatformTests.swift
@@ -0,0 +1,67 @@
+import XCTest
+@testable import ByteLystPlatformSDK
+
+final class ByteLystPlatformTests: XCTestCase {
+
+    private func makeConfig() -> BLPlatformConfig {
+        BLPlatformConfig(
+            productId: "testapp",
+            baseURL: "http://localhost:4003/api",
+            platform: "ios",
+            channel: "native",
+            bundleId: "com.bytelyst.test"
+        )
+    }
+
+    func testInitCreatesAllServices() {
+        let platform = ByteLystPlatform(config: makeConfig())
+        XCTAssertEqual(platform.config.productId, "testapp")
+        XCTAssertNotNil(platform.client)
+        XCTAssertNotNil(platform.telemetry)
+        XCTAssertNotNil(platform.flags)
+        XCTAssertNotNil(platform.killSwitch)
+        XCTAssertNotNil(platform.crashReporter)
+        XCTAssertNotNil(platform.keychain)
+        XCTAssertNotNil(platform.auditLog)
+        XCTAssertNotNil(platform.auth)
+    }
+
+    func testStartSetsIsStarted() {
+        let platform = ByteLystPlatform(config: makeConfig())
+        XCTAssertFalse(platform.isStarted)
+        platform.start()
+        XCTAssertTrue(platform.isStarted)
+    }
+
+    func testStopClearsIsStarted() {
+        let platform = ByteLystPlatform(config: makeConfig())
+        platform.start()
+        XCTAssertTrue(platform.isStarted)
+        platform.stop()
+        XCTAssertFalse(platform.isStarted)
+    }
+
+    func testDoubleStartIsIdempotent() {
+        let platform = ByteLystPlatform(config: makeConfig())
+        platform.start()
+        platform.start() // Should not crash or double-start
+        XCTAssertTrue(platform.isStarted)
+        platform.stop()
+    }
+
+    func testDoubleStopIsIdempotent() {
+        let platform = ByteLystPlatform(config: makeConfig())
+        platform.start()
+        platform.stop()
+        platform.stop() // Should not crash
+        XCTAssertFalse(platform.isStarted)
+    }
+
+    func testKeychainAccessor() {
+        let accessor = BLKeychainAccessor(service: "com.bytelyst.test.accessor")
+        accessor.save(key: "test_key", value: "hello")
+        XCTAssertEqual(accessor.read(key: "test_key"), "hello")
+        accessor.delete(key: "test_key")
+        XCTAssertNil(accessor.read(key: "test_key"))
+    }
+}