diff --git a/inngest-spring-boot-demo/src/main/java/com/inngest/springbootdemo/testfunctions/WithOnFailureFunction.java b/inngest-spring-boot-demo/src/main/java/com/inngest/springbootdemo/testfunctions/WithOnFailureFunction.java
index 6d2e6d72..4e9825db 100644
--- a/inngest-spring-boot-demo/src/main/java/com/inngest/springbootdemo/testfunctions/WithOnFailureFunction.java
+++ b/inngest-spring-boot-demo/src/main/java/com/inngest/springbootdemo/testfunctions/WithOnFailureFunction.java
@@ -4,7 +4,7 @@
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
-public class WithOnFailureFunction extends InngestFunction implements WithFailureHandler {
+public class WithOnFailureFunction extends InngestFunction {
     @NotNull
     @Override
     public InngestFunctionConfigBuilder config(InngestFunctionConfigBuilder builder) {
diff --git a/inngest-spring-boot-demo/src/test/java/com/inngest/springbootdemo/WithOnFailureIntegrationTest.java b/inngest-spring-boot-demo/src/test/java/com/inngest/springbootdemo/WithOnFailureIntegrationTest.java
index c45792f1..6a9647d7 100644
--- a/inngest-spring-boot-demo/src/test/java/com/inngest/springbootdemo/WithOnFailureIntegrationTest.java
+++ b/inngest-spring-boot-demo/src/test/java/com/inngest/springbootdemo/WithOnFailureIntegrationTest.java
@@ -19,11 +19,6 @@
 @IntegrationTest
 @Execution(ExecutionMode.CONCURRENT)
 class WithOnFailureIntegrationTest {
-    @BeforeAll
-    static void setup(@Autowired CommHandler handler) {
-        handler.register("http://localhost:8080");
-    }
-
     @Autowired
     private DevServerComponent devServer;
 
@@ -35,7 +30,7 @@ static void setup(@Autowired CommHandler handler) {
     @Test
     void testWithOnFailureShouldCallOnFailure() throws Exception {
         String eventName = "test/with-on-failure";
-        String eventId = InngestFunctionTestHelpers.sendEvent(client, eventName).first();
+        String eventId = InngestFunctionTestHelpers.sendEvent(client, eventName).getIds()[0];
 
         Thread.sleep(sleepTime);
 
diff --git a/inngest-test-server/src/main/kotlin/com/inngest/testserver/SlackFailureReport.kt b/inngest-test-server/src/main/kotlin/com/inngest/testserver/SlackFailureReport.kt
index dff8684b..e0ed2ef5 100644
--- a/inngest-test-server/src/main/kotlin/com/inngest/testserver/SlackFailureReport.kt
+++ b/inngest-test-server/src/main/kotlin/com/inngest/testserver/SlackFailureReport.kt
@@ -2,9 +2,7 @@ package com.inngest.testserver
 
 import com.inngest.*
 
-class SlackFailureReport :
-    InngestFunction(),
-    WithFailureHandler {
+class SlackFailureReport : InngestFunction() {
     override fun config(builder: InngestFunctionConfigBuilder): InngestFunctionConfigBuilder =
         builder
             .id("always-fail-fn")
diff --git a/inngest/src/main/kotlin/com/inngest/InngestFunction.kt b/inngest/src/main/kotlin/com/inngest/InngestFunction.kt
index 81b9119f..f116dcdc 100644
--- a/inngest/src/main/kotlin/com/inngest/InngestFunction.kt
+++ b/inngest/src/main/kotlin/com/inngest/InngestFunction.kt
@@ -30,7 +30,9 @@ abstract class InngestFunction {
     }
 
     internal fun toFailureHandler(appId: String): InternalInngestFunction? {
-        if (this is WithFailureHandler) {
+        val onFailureMethod = this.javaClass.getMethod("onFailure", FunctionContext::class.java, Step::class.java)
+
+        if (onFailureMethod.declaringClass != InngestFunction::class.java) {
             val fnConfig = buildConfig()
             val fullyQualifiedId = "$appId-${fnConfig.id}"
             val fnName = fnConfig.name ?: fnConfig.id
@@ -45,4 +47,20 @@ abstract class InngestFunction {
         }
         return null
     }
+
+    /**
+     * Provide a function to be called if your function fails, meaning
+     * that it ran out of retries and was unable to complete successfully.
+     *
+     * This is useful for sending warning notifications or cleaning up
+     * after a failure and supports all the same functionality as a
+     * regular handler.
+     *
+     * @param ctx The function context including event(s) that triggered the function
+     * @param step A class with methods to define steps within the function
+     */
+    open fun onFailure(
+        ctx: FunctionContext,
+        step: Step,
+    ): Any? = null
 }
diff --git a/inngest/src/main/kotlin/com/inngest/WithFailureHandler.kt b/inngest/src/main/kotlin/com/inngest/WithFailureHandler.kt
deleted file mode 100644
index c154a910..00000000
--- a/inngest/src/main/kotlin/com/inngest/WithFailureHandler.kt
+++ /dev/null
@@ -1,14 +0,0 @@
-package com.inngest
-
-interface WithFailureHandler {
-    /**
-     * Function to call when the Inngest function fails.
-     *
-     * @param ctx The function context including event(s) that triggered the function
-     * @param step A class with methods to define steps within the function
-     */
-    fun onFailure(
-        ctx: FunctionContext,
-        step: Step,
-    ): Any?
-}