diff --git a/README.md b/README.md
index d6ac4d4..b789be0 100644
--- a/README.md
+++ b/README.md
@@ -10,6 +10,10 @@ The GitExtension enhances versioning by dynamically appending the Git hash befor
 
 The InfoExtension provides information for name and version, vendor name, and UTC timestamp.
 
+### Extension Config
+
+The ConfigExtension provides a find or findOrDefault for getting a property or environment.
+
 ## Publish version catalog locally.
 
 ```shell
diff --git a/build.gradle.kts b/build.gradle.kts
index ad2a306..9c28767 100644
--- a/build.gradle.kts
+++ b/build.gradle.kts
@@ -19,6 +19,7 @@ plugins {
 dependencies {
     implementation(aa.jgit)
 
+    testImplementation(aa.assertj)
     testImplementation(aa.junit.jupiter.params)
     testImplementation(aa.kotlin.junit5)
     testImplementation(aa.mockk)
@@ -114,6 +115,8 @@ tasks {
         }
     }
     withType<Test> {
+        // Set TEST_ENV environment variable for test execution
+        environment["TEST_ENV"] = "lulz"
         useJUnitPlatform()
     }
 }
diff --git a/src/main/kotlin/ltd/lulz/plugin/CorePlugin.kt b/src/main/kotlin/ltd/lulz/plugin/CorePlugin.kt
index 00eaa36..a24fa80 100644
--- a/src/main/kotlin/ltd/lulz/plugin/CorePlugin.kt
+++ b/src/main/kotlin/ltd/lulz/plugin/CorePlugin.kt
@@ -1,9 +1,11 @@
 package ltd.lulz.plugin
 
+import ltd.lulz.plugin.extension.ConfigExtension
 import ltd.lulz.plugin.extension.GitExtension
 import ltd.lulz.plugin.extension.InfoExtension
 import org.gradle.api.Plugin
 import org.gradle.api.Project
+import ltd.lulz.plugin.extension.ConfigExtension.Companion.PLUGIN_NAME as CONFIG_PLUGIN_NAME
 import ltd.lulz.plugin.extension.GitExtension.Companion.PLUGIN_NAME as GIT_PLUGIN_NAME
 import ltd.lulz.plugin.extension.InfoExtension.Companion.PLUGIN_NAME as INFO_PLUGIN_NAME
 
@@ -18,8 +20,14 @@ class CorePlugin : Plugin<Project> {
     ) {
         gitExtension(project)
         infoExtension(project)
+        configExtension(project)
     }
 
+    private fun configExtension(
+        project: Project,
+    ): ConfigExtension = project.extensions
+        .create(CONFIG_PLUGIN_NAME, ConfigExtension::class.java, project)
+
     private fun infoExtension(
         project: Project,
     ): InfoExtension = project.extensions
diff --git a/src/main/kotlin/ltd/lulz/plugin/extension/ConfigExtension.kt b/src/main/kotlin/ltd/lulz/plugin/extension/ConfigExtension.kt
new file mode 100644
index 0000000..dc23fa0
--- /dev/null
+++ b/src/main/kotlin/ltd/lulz/plugin/extension/ConfigExtension.kt
@@ -0,0 +1,31 @@
+package ltd.lulz.plugin.extension
+
+import java.lang.System.getenv
+import org.gradle.api.Project
+
+abstract class ConfigExtension(private val project: Project) {
+
+    companion object {
+        const val PLUGIN_NAME = "config"
+        const val EMPTY = ""
+    }
+
+    fun find(
+        property: String,
+        environment: String,
+    ): String? = findProperty(property) ?: findEnvironment(environment)
+
+    fun findOrDefault(
+        property: String,
+        environment: String,
+        default: String = EMPTY,
+    ): String = findProperty(property) ?: findEnvironment(environment) ?: default
+
+    private fun findProperty(
+        property: String,
+    ) = project.findProperty(property)?.toString()
+
+    private fun findEnvironment(
+        environment: String,
+    ): String? = getenv(environment)
+}
diff --git a/src/test/kotlin/ltd/lulz/plugin/extension/ConfigExtensionTest.kt b/src/test/kotlin/ltd/lulz/plugin/extension/ConfigExtensionTest.kt
new file mode 100644
index 0000000..c684eb7
--- /dev/null
+++ b/src/test/kotlin/ltd/lulz/plugin/extension/ConfigExtensionTest.kt
@@ -0,0 +1,112 @@
+package ltd.lulz.plugin.extension
+
+import org.assertj.core.api.Assertions.assertThat
+import org.gradle.api.Project
+import org.gradle.testfixtures.ProjectBuilder
+import org.junit.jupiter.api.BeforeEach
+import org.junit.jupiter.api.Nested
+import org.junit.jupiter.api.Test
+
+/**
+ * This test uses TEST_ENV set in gradle test task, and project extension to pretend to be a project property.
+ */
+class ConfigExtensionTest {
+
+    companion object {
+        const val EXTENSION = "config"
+        const val PLUGIN_ID = "ltd.lulz.plugin.core-plugin"
+        const val PROJECT_NAME = "test-project"
+        const val SNAPSHOT_VERSION = "0.0.0-SNAPSHOT"
+    }
+
+    lateinit var project: Project
+
+    lateinit var configExtension: ConfigExtension
+
+    @BeforeEach
+    fun beforeEach() {
+        project = ProjectBuilder.builder()
+            .withName(PROJECT_NAME)
+            .build()
+        project.version = SNAPSHOT_VERSION
+        project.pluginManager.apply(PLUGIN_ID)
+        project.extensions.add(
+            "testProperty",
+            object {
+                override fun toString(): String = "lulz"
+            },
+        )
+        configExtension = project.extensions.getByName(EXTENSION) as ConfigExtension
+    }
+
+    @Nested
+    inner class FindTest {
+
+        @Test
+        fun `property or environment find property`() {
+            // when
+            val result = configExtension.find("testProperty", "TEST_PROPERTY")
+
+            // then
+            assertThat(result).isEqualTo("lulz")
+        }
+
+        @Test
+        fun `property or environment find environment`() {
+            // when
+            val result = configExtension.find("test_env", "TEST_ENV")
+
+            // then
+            assertThat(result).isEqualTo("lulz")
+        }
+
+        @Test
+        fun `property or environment find nothing`() {
+            // when
+            val result = configExtension.find("test", "TEST")
+
+            // then
+            assertThat(result).isNull()
+        }
+    }
+
+    @Nested
+    inner class FindOrDefaultTest {
+
+        @Test
+        fun `property, environment, or default find property`() {
+            // when
+            val result = configExtension.findOrDefault("testProperty", "TEST_PROPERTY")
+
+            // then
+            assertThat(result).isEqualTo("lulz")
+        }
+
+        @Test
+        fun `property, environment, or default find environment`() {
+            // when
+            val result = configExtension.findOrDefault("test_env", "TEST_ENV")
+
+            // then
+            assertThat(result).isEqualTo("lulz")
+        }
+
+        @Test
+        fun `property, environment, or default find empty`() {
+            // when
+            val result = configExtension.findOrDefault("test", "TEST")
+
+            // then
+            assertThat(result).isEmpty()
+        }
+
+        @Test
+        fun `property, environment, or default find defined response`() {
+            // when
+            val result = configExtension.findOrDefault("test", "TEST", "value")
+
+            // then
+            assertThat(result).isEqualTo("value")
+        }
+    }
+}