diff --git a/.changeset/fresh-keys-bow.md b/.changeset/fresh-keys-bow.md
new file mode 100644
index 00000000..8d03268e
--- /dev/null
+++ b/.changeset/fresh-keys-bow.md
@@ -0,0 +1,6 @@
+---
+"posthog": patch
+"posthog-android": patch
+---
+
+No-op SDK setup when the API key is null, empty, or whitespace after trimming.
diff --git a/posthog-android/src/main/java/com/posthog/android/PostHogAndroid.kt b/posthog-android/src/main/java/com/posthog/android/PostHogAndroid.kt
index 2505fb13..cf65f686 100644
--- a/posthog-android/src/main/java/com/posthog/android/PostHogAndroid.kt
+++ b/posthog-android/src/main/java/com/posthog/android/PostHogAndroid.kt
@@ -47,6 +47,11 @@ public class PostHogAndroid private constructor() {
             config: T,
         ) {
             synchronized(lock) {
+                if (config.apiKey.isEmpty()) {
+                    PostHog.setup(config)
+                    return
+                }
+
                 setAndroidConfig(context.appContext(), config)
 
                 PostHog.setup(config)
@@ -69,6 +74,10 @@ public class PostHogAndroid private constructor() {
             context: Context,
             config: T,
         ): PostHogInterface {
+            if (config.apiKey.isEmpty()) {
+                return PostHog.with(config)
+            }
+
             setAndroidConfig(context.appContext(), config)
             return PostHog.with(config)
         }
diff --git a/posthog-android/src/main/java/com/posthog/android/PostHogAndroidConfig.kt b/posthog-android/src/main/java/com/posthog/android/PostHogAndroidConfig.kt
index f2302f5c..614930df 100644
--- a/posthog-android/src/main/java/com/posthog/android/PostHogAndroidConfig.kt
+++ b/posthog-android/src/main/java/com/posthog/android/PostHogAndroidConfig.kt
@@ -13,7 +13,7 @@ import com.posthog.android.replay.PostHogSessionReplayConfig
 public open class PostHogAndroidConfig
     @JvmOverloads
     constructor(
-        apiKey: String,
+        apiKey: String?,
         host: String = DEFAULT_HOST,
         public var captureApplicationLifecycleEvents: Boolean = true,
         public var captureDeepLinks: Boolean = true,
diff --git a/posthog-android/src/test/java/com/posthog/android/PostHogAndroidConfigJavaTest.java b/posthog-android/src/test/java/com/posthog/android/PostHogAndroidConfigJavaTest.java
new file mode 100644
index 00000000..c5efc48f
--- /dev/null
+++ b/posthog-android/src/test/java/com/posthog/android/PostHogAndroidConfigJavaTest.java
@@ -0,0 +1,14 @@
+package com.posthog.android;
+
+import org.junit.Test;
+
+import static org.junit.Assert.assertEquals;
+
+public class PostHogAndroidConfigJavaTest {
+    @Test
+    public void nullApiKeyFromJavaDefaultsToEmptyString() {
+        PostHogAndroidConfig config = new PostHogAndroidConfig(null);
+
+        assertEquals("", config.getApiKey());
+    }
+}
diff --git a/posthog-android/src/test/java/com/posthog/android/PostHogAndroidConfigTest.kt b/posthog-android/src/test/java/com/posthog/android/PostHogAndroidConfigTest.kt
index 122ba641..c2af8c12 100644
--- a/posthog-android/src/test/java/com/posthog/android/PostHogAndroidConfigTest.kt
+++ b/posthog-android/src/test/java/com/posthog/android/PostHogAndroidConfigTest.kt
@@ -12,6 +12,13 @@ internal class PostHogAndroidConfigTest {
         assertEquals(API_KEY, config.apiKey)
     }
 
+    @Test
+    fun `defaults null api key to empty string`() {
+        val config = PostHogAndroidConfig(null)
+
+        assertEquals("", config.apiKey)
+    }
+
     @Test
     fun `captureApplicationLifecycleEvents should be enabled by default`() {
         assertTrue(config.captureApplicationLifecycleEvents)
diff --git a/posthog-android/src/test/java/com/posthog/android/PostHogAndroidTest.kt b/posthog-android/src/test/java/com/posthog/android/PostHogAndroidTest.kt
index e4ab9f59..8c62fda6 100644
--- a/posthog-android/src/test/java/com/posthog/android/PostHogAndroidTest.kt
+++ b/posthog-android/src/test/java/com/posthog/android/PostHogAndroidTest.kt
@@ -39,6 +39,26 @@ internal class PostHogAndroidTest {
         tmpDir.root.deleteRecursively()
     }
 
+    @Test
+    fun `setup no-ops for null api key`() {
+        val config = PostHogAndroidConfig(null)
+
+        PostHogAndroid.setup(context, config)
+
+        assertNull(config.cachePreferences)
+        assertTrue(config.integrations.isEmpty())
+    }
+
+    @Test
+    fun `setup no-ops for empty trimmed api key`() {
+        val config = PostHogAndroidConfig(" \n\t ")
+
+        PostHogAndroid.setup(context, config)
+
+        assertNull(config.cachePreferences)
+        assertTrue(config.integrations.isEmpty())
+    }
+
     @Test
     fun `sets Android Logger if System logger`() {
         val config = PostHogAndroidConfig(API_KEY)
diff --git a/posthog/src/main/java/com/posthog/PostHog.kt b/posthog/src/main/java/com/posthog/PostHog.kt
index 82c6a68c..8994d9bb 100644
--- a/posthog/src/main/java/com/posthog/PostHog.kt
+++ b/posthog/src/main/java/com/posthog/PostHog.kt
@@ -101,6 +101,7 @@ public class PostHog private constructor(
 
                 if (config.apiKey.isEmpty()) {
                     config.logger.log("apiKey is empty after trimming whitespace; check your project API key")
+                    return
                 }
 
                 if (!apiKeys.add(config.apiKey)) {
diff --git a/posthog/src/main/java/com/posthog/PostHogConfig.kt b/posthog/src/main/java/com/posthog/PostHogConfig.kt
index 5f6f4e61..fe57b995 100644
--- a/posthog/src/main/java/com/posthog/PostHogConfig.kt
+++ b/posthog/src/main/java/com/posthog/PostHogConfig.kt
@@ -31,7 +31,7 @@ public open class PostHogConfig(
     /**
      * The PostHog API Key
      */
-    apiKey: String,
+    apiKey: String?,
     /**
      * The PostHog Host
      * Defaults to https://us.i.posthog.com
@@ -328,7 +328,7 @@ public open class PostHogConfig(
     /**
      * The PostHog API Key
      */
-    public val apiKey: String = apiKey.trim()
+    public val apiKey: String = apiKey?.trim().orEmpty()
 
     /**
      * The PostHog Host
diff --git a/posthog/src/main/java/com/posthog/PostHogStateless.kt b/posthog/src/main/java/com/posthog/PostHogStateless.kt
index 313163d7..ecf9e369 100644
--- a/posthog/src/main/java/com/posthog/PostHogStateless.kt
+++ b/posthog/src/main/java/com/posthog/PostHogStateless.kt
@@ -55,6 +55,7 @@ public open class PostHogStateless protected constructor(
 
                 if (config.apiKey.isEmpty()) {
                     config.logger.log("apiKey is empty after trimming whitespace; check your project API key")
+                    return
                 }
 
                 if (!apiKeys.add(config.apiKey)) {
diff --git a/posthog/src/test/java/com/posthog/PostHogConfigTest.kt b/posthog/src/test/java/com/posthog/PostHogConfigTest.kt
index 86bd00ef..6d5f8199 100644
--- a/posthog/src/test/java/com/posthog/PostHogConfigTest.kt
+++ b/posthog/src/test/java/com/posthog/PostHogConfigTest.kt
@@ -23,6 +23,13 @@ internal class PostHogConfigTest {
         assertEquals("https://eu.i.posthog.com/", config.host)
     }
 
+    @Test
+    fun `defaults null api key to empty string`() {
+        val config = PostHogConfig(null, "https://api.posthog.com")
+
+        assertEquals("", config.apiKey)
+    }
+
     @Test
     fun `defaults a blank host after trimming whitespace`() {
         val config = PostHogConfig(API_KEY, " \n\t ")
diff --git a/posthog/src/test/java/com/posthog/PostHogStatelessTest.kt b/posthog/src/test/java/com/posthog/PostHogStatelessTest.kt
index 98f6355c..f39da0eb 100644
--- a/posthog/src/test/java/com/posthog/PostHogStatelessTest.kt
+++ b/posthog/src/test/java/com/posthog/PostHogStatelessTest.kt
@@ -237,13 +237,14 @@ internal class PostHogStatelessTest {
     }
 
     @Test
-    fun `setup logs empty trimmed api key after logger initialization`() {
+    fun `setup no-ops for empty trimmed api key after logger initialization`() {
         sut = createStatelessInstance()
         val mockLogger = MockLogger()
         config = PostHogConfig(" \n\t ", "https://api.posthog.com").apply { logger = mockLogger }
 
         sut.setup(config)
 
+        assertFalse(sut.isEnabledPublic())
         assertTrue(mockLogger.messages.any { it.contains("apiKey is empty after trimming whitespace") })
     }
 
diff --git a/posthog/src/test/java/com/posthog/PostHogTest.kt b/posthog/src/test/java/com/posthog/PostHogTest.kt
index 79b6052e..4809311a 100644
--- a/posthog/src/test/java/com/posthog/PostHogTest.kt
+++ b/posthog/src/test/java/com/posthog/PostHogTest.kt
@@ -126,6 +126,25 @@ internal class PostHogTest {
         sut.close()
     }
 
+    @Test
+    fun `setup no-ops for empty trimmed api key`() {
+        val config = PostHogConfig(" \n\t ", "https://api.posthog.com")
+        val sut =
+            PostHog.withInternal(
+                config,
+                queueExecutor,
+                replayQueueExecutor,
+                remoteConfigExecutor,
+                cachedEventsExecutor,
+                reloadFeatureFlags = true,
+            )
+
+        assertTrue(config.integrations.isEmpty())
+        assertNull(config.cachePreferences)
+
+        sut.close()
+    }
+
     @Test
     fun `setup adds integration by default`() {
         val http = mockHttp()