diff --git a/api/.gitignore b/api/.gitignore
new file mode 100644
index 000000000..796b96d1c
--- /dev/null
+++ b/api/.gitignore
@@ -0,0 +1 @@
+/build
diff --git a/api/README.md b/api/README.md
new file mode 100644
index 000000000..0a58d3927
--- /dev/null
+++ b/api/README.md
@@ -0,0 +1,6 @@
+# API module
+
+This module contains the public API interfaces and types exposed to consumers of the Split SDK.
+
+Classes in this module are part of the public API contract and should maintain backwards compatibility.
+
diff --git a/api/build.gradle b/api/build.gradle
new file mode 100644
index 000000000..c32f26549
--- /dev/null
+++ b/api/build.gradle
@@ -0,0 +1,22 @@
+plugins {
+ id 'com.android.library'
+}
+
+apply from: "$rootDir/gradle/common-android-library.gradle"
+
+android {
+ namespace 'io.split.android.client.api'
+
+ compileOptions {
+ sourceCompatibility JavaVersion.VERSION_1_8
+ targetCompatibility JavaVersion.VERSION_1_8
+ }
+}
+
+dependencies {
+ implementation libs.annotation
+
+ testImplementation libs.junit4
+ testImplementation libs.mockitoCore
+}
+
diff --git a/api/consumer-rules.pro b/api/consumer-rules.pro
new file mode 100644
index 000000000..e69de29bb
diff --git a/api/proguard-rules.pro b/api/proguard-rules.pro
new file mode 100644
index 000000000..cf504086a
--- /dev/null
+++ b/api/proguard-rules.pro
@@ -0,0 +1,22 @@
+# Add project specific ProGuard rules here.
+# You can control the set of applied configuration files using the
+# proguardFiles setting in build.gradle.
+#
+# For more details, see
+# http://developer.android.com/guide/developing/tools/proguard.html
+
+# If your project uses WebView with JS, uncomment the following
+# and specify the fully qualified class name to the JavaScript interface
+# class:
+#-keepclassmembers class fqcn.of.javascript.interface.for.webview {
+# public *;
+#}
+
+# Uncomment this to preserve the line number information for
+# debugging stack traces.
+#-keepattributes SourceFile,LineNumberTable
+
+# If you keep the line number information, uncomment this to
+# hide the original source file name.
+#-renamesourcefileattribute SourceFile
+
diff --git a/api/src/androidTest/java/.gitkeep b/api/src/androidTest/java/.gitkeep
new file mode 100644
index 000000000..e69de29bb
diff --git a/api/src/main/AndroidManifest.xml b/api/src/main/AndroidManifest.xml
new file mode 100644
index 000000000..cf2d636b6
--- /dev/null
+++ b/api/src/main/AndroidManifest.xml
@@ -0,0 +1,5 @@
+
+
+
+
+
diff --git a/api/src/main/java/io/split/android/client/api/EventMetadata.java b/api/src/main/java/io/split/android/client/api/EventMetadata.java
new file mode 100644
index 000000000..e1648c388
--- /dev/null
+++ b/api/src/main/java/io/split/android/client/api/EventMetadata.java
@@ -0,0 +1,58 @@
+package io.split.android.client.api;
+
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+
+import java.util.Collection;
+import java.util.Map;
+import java.util.Set;
+
+/**
+ * Represents metadata associated with SDK events.
+ *
+ * Values are sanitized to only allow String, Number, Boolean, or List<String>.
+ */
+public interface EventMetadata {
+
+ /**
+ * Returns the set of keys in this metadata.
+ *
+ * @return set of keys
+ */
+ @NonNull
+ Set keys();
+
+ /**
+ * Returns the collection of values in this metadata.
+ *
+ * @return collection of values
+ */
+ @NonNull
+ Collection