diff --git a/aws/sdk-codegen/src/main/kotlin/software/amazon/smithy/rustsdk/EndpointBuiltInsDecorator.kt b/aws/sdk-codegen/src/main/kotlin/software/amazon/smithy/rustsdk/EndpointBuiltInsDecorator.kt
index e59eaa7bc8..c202b5c4cd 100644
--- a/aws/sdk-codegen/src/main/kotlin/software/amazon/smithy/rustsdk/EndpointBuiltInsDecorator.kt
+++ b/aws/sdk-codegen/src/main/kotlin/software/amazon/smithy/rustsdk/EndpointBuiltInsDecorator.kt
@@ -57,7 +57,9 @@ fun ClientCodegenContext.getBuiltIn(builtIn: String): Parameter? {
 }
 
 private fun promotedBuiltins(parameter: Parameter) =
-    parameter == Builtins.FIPS || parameter == Builtins.DUALSTACK || parameter == Builtins.SDK_ENDPOINT
+    parameter.builtIn == Builtins.FIPS.builtIn ||
+        parameter.builtIn == Builtins.DUALSTACK.builtIn ||
+        parameter.builtIn == Builtins.SDK_ENDPOINT.builtIn
 
 private fun configParamNewtype(parameter: Parameter, name: String, runtimeConfig: RuntimeConfig): RuntimeType {
     val type = parameter.symbol().mapRustType { t -> t.stripOuter<RustType.Option>() }
@@ -204,6 +206,9 @@ val PromotedBuiltInsDecorators =
         decoratorForBuiltIn(Builtins.DUALSTACK),
         decoratorForBuiltIn(
             Builtins.SDK_ENDPOINT,
-            ConfigParam.Builder().name("endpoint_url").type(RuntimeType.String.toSymbol()).setterDocs(endpointUrlDocs),
+            ConfigParam.Builder()
+                .name("endpoint_url")
+                .type(RuntimeType.String.toSymbol())
+                .setterDocs(endpointUrlDocs),
         ),
     ).toTypedArray()
diff --git a/aws/sdk-codegen/src/test/kotlin/software/amazon/smithy/rustsdk/EndpointBuiltInsDecoratorTest.kt b/aws/sdk-codegen/src/test/kotlin/software/amazon/smithy/rustsdk/EndpointBuiltInsDecoratorTest.kt
new file mode 100644
index 0000000000..ad84fb54df
--- /dev/null
+++ b/aws/sdk-codegen/src/test/kotlin/software/amazon/smithy/rustsdk/EndpointBuiltInsDecoratorTest.kt
@@ -0,0 +1,119 @@
+/*
+ * Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package software.amazon.smithy.rustsdk
+
+import org.junit.jupiter.api.Test
+import software.amazon.smithy.rust.codegen.core.rustlang.CargoDependency
+import software.amazon.smithy.rust.codegen.core.rustlang.rustTemplate
+import software.amazon.smithy.rust.codegen.core.smithy.RuntimeType
+import software.amazon.smithy.rust.codegen.core.testutil.asSmithyModel
+import software.amazon.smithy.rust.codegen.core.testutil.integrationTest
+
+class EndpointBuiltInsDecoratorTest {
+    private val endpointUrlModel = """
+        namespace test
+
+        use aws.api#service
+        use aws.auth#sigv4
+        use aws.protocols#restJson1
+        use smithy.rules#endpointRuleSet
+
+        @service(sdkId: "dontcare")
+        @restJson1
+        @sigv4(name: "dontcare")
+        @auth([sigv4])
+        @endpointRuleSet({
+            "version": "1.0"
+            "parameters": {
+                "endpoint": { "required": false, "type": "string", "builtIn": "SDK::Endpoint" },
+                "region": { "required": false, "type": "String", "builtIn": "AWS::Region" },
+            }
+            "rules": [
+                {
+                    "type": "endpoint"
+                    "conditions": [
+                        {"fn": "isSet", "argv": [{"ref": "endpoint"}]},
+                        {"fn": "isSet", "argv": [{"ref": "region"}]}
+                    ],
+                    "endpoint": {
+                        "url": "{endpoint}"
+                        "properties": {
+                            "authSchemes": [{"name": "sigv4","signingRegion": "{region}"}]
+                        }
+                    }
+                },
+                {
+                    "type": "endpoint"
+                    "conditions": [
+                        {"fn": "isSet", "argv": [{"ref": "region"}]},
+                    ],
+                    "endpoint": {
+                        "url": "https://WRONG/"
+                        "properties": {
+                            "authSchemes": [{"name": "sigv4", "signingRegion": "{region}"}]
+                        }
+                    }
+                }
+            ]
+        })
+        service TestService {
+            version: "2023-01-01",
+            operations: [SomeOperation]
+        }
+
+        structure SomeOutput {
+            someAttribute: Long,
+            someVal: String
+        }
+
+        @http(uri: "/SomeOperation", method: "GET")
+        @optionalAuth
+        operation SomeOperation {
+            output: SomeOutput
+        }
+    """.asSmithyModel()
+
+    @Test
+    fun endpointUrlBuiltInWorksEndToEnd() {
+        awsSdkIntegrationTest(
+            endpointUrlModel,
+            generateOrchestrator = true,
+        ) { codegenContext, rustCrate ->
+            rustCrate.integrationTest("endpoint_url_built_in_works") {
+                val module = codegenContext.moduleUseName()
+                rustTemplate(
+                    """
+                    use $module::{Config, Client, config::Region};
+
+                    ##[#{tokio}::test]
+                    async fn endpoint_url_built_in_works() {
+                        let connector = #{TestConnection}::new(vec![(
+                            http::Request::builder()
+                                .uri("https://RIGHT/SomeOperation")
+                                .body(#{SdkBody}::empty())
+                                .unwrap(),
+                            http::Response::builder().status(200).body("").unwrap(),
+                        )]);
+                        let config = Config::builder()
+                            .http_connector(connector.clone())
+                            .region(Region::new("us-east-1"))
+                            .endpoint_url("https://RIGHT")
+                            .build();
+                        let client = Client::from_conf(config);
+                        dbg!(client.some_operation().send().await).expect("success");
+                        connector.assert_requests_match(&[]);
+                    }
+                    """,
+                    "tokio" to CargoDependency.Tokio.toDevDependency().withFeature("rt").withFeature("macros").toType(),
+                    "TestConnection" to CargoDependency.smithyClient(codegenContext.runtimeConfig)
+                        .toDevDependency().withFeature("test-util").toType()
+                        .resolve("test_connection::TestConnection"),
+                    "SdkBody" to RuntimeType.sdkBody(codegenContext.runtimeConfig),
+                )
+            }
+        }
+    }
+}
diff --git a/aws/sdk-codegen/src/test/kotlin/software/amazon/smithy/rustsdk/TestUtil.kt b/aws/sdk-codegen/src/test/kotlin/software/amazon/smithy/rustsdk/TestUtil.kt
index 44ed5461a9..3dc959abce 100644
--- a/aws/sdk-codegen/src/test/kotlin/software/amazon/smithy/rustsdk/TestUtil.kt
+++ b/aws/sdk-codegen/src/test/kotlin/software/amazon/smithy/rustsdk/TestUtil.kt
@@ -6,6 +6,7 @@
 package software.amazon.smithy.rustsdk
 
 import software.amazon.smithy.model.Model
+import software.amazon.smithy.model.node.BooleanNode
 import software.amazon.smithy.model.node.ObjectNode
 import software.amazon.smithy.model.node.StringNode
 import software.amazon.smithy.rust.codegen.client.smithy.ClientCodegenContext
@@ -65,6 +66,7 @@ fun awsSdkIntegrationTest(
                         .withMember("includeFluentClient", false)
                         .letIf(generateOrchestrator) {
                             it.withMember("enableNewSmithyRuntime", StringNode.from("orchestrator"))
+                                .withMember("includeEndpointUrlConfig", BooleanNode.from(false))
                         }
                         .build(),
                 ).build(),