diff --git a/CHANGELOG.md b/CHANGELOG.md
index d82cd45164..28bd424737 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -15,6 +15,7 @@ The changelog for `SuperwallKit`. Also see the [releases](https://github.com/sup
 
 - Fixes issue with compiling on Xcode 26.4 beta.
 - Fixes dashboard display of multiple active entitlements.
+- Makes `device.isSandbox` more reliable.
 
 ## 4.13.0
 
diff --git a/Sources/SuperwallKit/Network/Device Helper/DeviceHelper.swift b/Sources/SuperwallKit/Network/Device Helper/DeviceHelper.swift
index 41812f290f..f5512bc875 100644
--- a/Sources/SuperwallKit/Network/Device Helper/DeviceHelper.swift	
+++ b/Sources/SuperwallKit/Network/Device Helper/DeviceHelper.swift	
@@ -192,6 +192,13 @@ class DeviceHelper {
       return "true"
     #else
 
+    // Prefer AppTransaction.environment (iOS 16+) when available,
+    // as it reliably detects sandbox for all purchase types including
+    // Stripe and non-StoreKit flows.
+    if let isSandbox = ReceiptManager.isSandboxEnvironment {
+      return "\(isSandbox)"
+    }
+
     guard let url = Bundle.main.appStoreReceiptURL else {
       return "false"
     }
diff --git a/Sources/SuperwallKit/StoreKit/Products/Receipt Manager/Receipt Manager/ReceiptManager.swift b/Sources/SuperwallKit/StoreKit/Products/Receipt Manager/Receipt Manager/ReceiptManager.swift
index 60672ac564..ef82f876e6 100644
--- a/Sources/SuperwallKit/StoreKit/Products/Receipt Manager/Receipt Manager/ReceiptManager.swift	
+++ b/Sources/SuperwallKit/StoreKit/Products/Receipt Manager/Receipt Manager/ReceiptManager.swift	
@@ -32,6 +32,9 @@ actor ReceiptManager {
   private unowned let storage: Storage
   static var appTransactionId: String?
   static var appId: UInt64?
+  /// Set from `AppTransaction.shared` when available (iOS 16+).
+  /// `true` means sandbox, `false` means production, `nil` means not yet determined.
+  static var isSandboxEnvironment: Bool?
 
   init(
     storeKitVersion: SuperwallOptions.StoreKitVersion,
@@ -91,6 +94,7 @@ actor ReceiptManager {
           .unverified(let transaction, _):
           Self.appTransactionId = transaction.appTransactionID
           Self.appId = transaction.appID
+          Self.isSandboxEnvironment = transaction.environment == .sandbox || transaction.environment == .xcode
           if Superwall.isInitialized {
             registerAppTransactionIdIfNeeded()
             Superwall.shared.dequeueIntegrationAttributes()
diff --git a/Tests/SuperwallKitTests/StoreKit/Products/Receipt Manager/ReceiptManagerTests.swift b/Tests/SuperwallKitTests/StoreKit/Products/Receipt Manager/ReceiptManagerTests.swift
index e25409f156..1568e0346e 100644
--- a/Tests/SuperwallKitTests/StoreKit/Products/Receipt Manager/ReceiptManagerTests.swift	
+++ b/Tests/SuperwallKitTests/StoreKit/Products/Receipt Manager/ReceiptManagerTests.swift	
@@ -79,7 +79,27 @@ class ReceiptManagerTests: XCTestCase {
   }
 
   func test_isFreeTrialAvailable() {
-    
+
+  }
+
+  func test_isSandboxEnvironment_defaultsToNil() {
+    // Reset to default state
+    ReceiptManager.isSandboxEnvironment = nil
+    XCTAssertNil(ReceiptManager.isSandboxEnvironment)
+  }
+
+  func test_isSandboxEnvironment_canBeSetToTrue() {
+    ReceiptManager.isSandboxEnvironment = true
+    XCTAssertEqual(ReceiptManager.isSandboxEnvironment, true)
+    // Clean up
+    ReceiptManager.isSandboxEnvironment = nil
+  }
+
+  func test_isSandboxEnvironment_canBeSetToFalse() {
+    ReceiptManager.isSandboxEnvironment = false
+    XCTAssertEqual(ReceiptManager.isSandboxEnvironment, false)
+    // Clean up
+    ReceiptManager.isSandboxEnvironment = nil
   }
   /*
   // MARK: - Test processing of receipt data