diff --git a/firebase-vertexai/src/main/kotlin/com/google/firebase/vertexai/type/ApiVersion.kt b/firebase-vertexai/src/main/kotlin/com/google/firebase/vertexai/type/ApiVersion.kt
new file mode 100644
index 00000000000..c8b11fd4451
--- /dev/null
+++ b/firebase-vertexai/src/main/kotlin/com/google/firebase/vertexai/type/ApiVersion.kt
@@ -0,0 +1,28 @@
+/*
+ * Copyright 2025 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.google.firebase.vertexai.type
+
+/** Versions of the Vertex AI in Firebase server API. */
+public class ApiVersion private constructor(internal val value: String) {
+  public companion object {
+    /** The stable channel for version 1 of the API. */
+    @JvmField public val V1: ApiVersion = ApiVersion("v1")
+
+    /** The beta channel for version 1 of the API. */
+    @JvmField public val V1BETA: ApiVersion = ApiVersion("v1beta")
+  }
+}
diff --git a/firebase-vertexai/src/main/kotlin/com/google/firebase/vertexai/type/RequestOptions.kt b/firebase-vertexai/src/main/kotlin/com/google/firebase/vertexai/type/RequestOptions.kt
index 9aa648b6d07..e2d2ff36b36 100644
--- a/firebase-vertexai/src/main/kotlin/com/google/firebase/vertexai/type/RequestOptions.kt
+++ b/firebase-vertexai/src/main/kotlin/com/google/firebase/vertexai/type/RequestOptions.kt
@@ -17,7 +17,6 @@
 package com.google.firebase.vertexai.type
 
 import kotlin.time.Duration
-import kotlin.time.Duration.Companion.seconds
 import kotlin.time.DurationUnit
 import kotlin.time.toDuration
 
@@ -25,8 +24,8 @@ import kotlin.time.toDuration
 public class RequestOptions
 internal constructor(
   internal val timeout: Duration,
-  internal val endpoint: String = "https://firebasevertexai.googleapis.com",
-  internal val apiVersion: String = "v1beta",
+  internal val endpoint: String = DEFAULT_ENDPOINT,
+  internal val apiVersion: String = DEFAULT_API_VERSION.value,
 ) {
 
   /**
@@ -34,9 +33,35 @@ internal constructor(
    *
    * @param timeoutInMillis the maximum amount of time, in milliseconds, for a request to take, from
    * the first request to first response.
+   * @param apiVersion the version of the Vertex AI in Firebase API; defaults to [ApiVersion.V1BETA]
+   * if not specified.
    */
   @JvmOverloads
   public constructor(
-    timeoutInMillis: Long = 180.seconds.inWholeMilliseconds
-  ) : this(timeout = timeoutInMillis.toDuration(DurationUnit.MILLISECONDS))
+    timeoutInMillis: Long = DEFAULT_TIMEOUT_IN_MILLIS,
+    apiVersion: ApiVersion = DEFAULT_API_VERSION,
+  ) : this(
+    timeout = timeoutInMillis.toDuration(DurationUnit.MILLISECONDS),
+    apiVersion = apiVersion.value,
+  )
+
+  /**
+   * Constructor for RequestOptions.
+   *
+   * @param apiVersion the version of the Vertex AI in Firebase API; defaults to [ApiVersion.V1BETA]
+   * if not specified.
+   */
+  public constructor(
+    apiVersion: ApiVersion
+  ) : this(
+    timeoutInMillis = DEFAULT_TIMEOUT_IN_MILLIS,
+    apiVersion = apiVersion,
+  )
+
+  internal companion object {
+    internal const val DEFAULT_TIMEOUT_IN_MILLIS: Long = 180_000L
+    internal const val DEFAULT_ENDPOINT: String = "https://firebasevertexai.googleapis.com"
+
+    internal val DEFAULT_API_VERSION: ApiVersion = ApiVersion.V1BETA
+  }
 }
diff --git a/firebase-vertexai/src/test/java/com/google/firebase/vertexai/GenerativeModelTesting.kt b/firebase-vertexai/src/test/java/com/google/firebase/vertexai/GenerativeModelTesting.kt
index 8b668371a31..f20ab347c3a 100644
--- a/firebase-vertexai/src/test/java/com/google/firebase/vertexai/GenerativeModelTesting.kt
+++ b/firebase-vertexai/src/test/java/com/google/firebase/vertexai/GenerativeModelTesting.kt
@@ -60,7 +60,7 @@ internal class GenerativeModelTesting {
       APIController(
         "super_cool_test_key",
         "gemini-1.5-flash",
-        RequestOptions(timeout = 5.seconds, endpoint = "https://my.custom.endpoint"),
+        RequestOptions(5.seconds.inWholeMilliseconds),
         mockEngine,
         TEST_CLIENT_ID,
         null,
diff --git a/firebase-vertexai/src/test/java/com/google/firebase/vertexai/api/java/JavaPublicApiTests.java b/firebase-vertexai/src/test/java/com/google/firebase/vertexai/api/java/JavaPublicApiTests.java
new file mode 100644
index 00000000000..cf271c42905
--- /dev/null
+++ b/firebase-vertexai/src/test/java/com/google/firebase/vertexai/api/java/JavaPublicApiTests.java
@@ -0,0 +1,31 @@
+/*
+ * Copyright 2025 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.google.firebase.vertexai.api.java;
+
+import com.google.firebase.vertexai.type.ApiVersion;
+import com.google.firebase.vertexai.type.RequestOptions;
+
+/** Build tests for the Vertex AI in Firebase Java public API surface. */
+final class JavaPublicApiTests {
+  /** {@link RequestOptions} API */
+  void requestOptionsCodeSamples() {
+    new RequestOptions();
+    new RequestOptions(30_000L);
+    new RequestOptions(ApiVersion.V1);
+    new RequestOptions(60_000L, ApiVersion.V1BETA);
+  }
+}
diff --git a/firebase-vertexai/src/test/java/com/google/firebase/vertexai/common/APIControllerTests.kt b/firebase-vertexai/src/test/java/com/google/firebase/vertexai/common/APIControllerTests.kt
index 8937b13569b..ffc3e352d3d 100644
--- a/firebase-vertexai/src/test/java/com/google/firebase/vertexai/common/APIControllerTests.kt
+++ b/firebase-vertexai/src/test/java/com/google/firebase/vertexai/common/APIControllerTests.kt
@@ -26,11 +26,14 @@ import com.google.firebase.vertexai.common.util.commonTest
 import com.google.firebase.vertexai.common.util.createResponses
 import com.google.firebase.vertexai.common.util.doBlocking
 import com.google.firebase.vertexai.common.util.prepareStreamingResponse
+import com.google.firebase.vertexai.type.ApiVersion
 import com.google.firebase.vertexai.type.RequestOptions
 import io.kotest.assertions.json.shouldContainJsonKey
 import io.kotest.assertions.throwables.shouldThrow
 import io.kotest.matchers.shouldBe
+import io.kotest.matchers.shouldNotBe
 import io.kotest.matchers.string.shouldContain
+import io.kotest.matchers.string.shouldStartWith
 import io.ktor.client.engine.mock.MockEngine
 import io.ktor.client.engine.mock.respond
 import io.ktor.content.TextContent
@@ -74,7 +77,7 @@ internal class APIControllerTests {
 
   @Test
   fun `(generateContent) respects a custom timeout`() =
-    commonTest(requestOptions = RequestOptions(2.seconds)) {
+    commonTest(requestOptions = RequestOptions(2.seconds.inWholeMilliseconds)) {
       shouldThrow<RequestTimeoutException> {
         withTimeout(testTimeout) {
           apiController.generateContent(textGenerateContentRequest("test"))
@@ -122,7 +125,11 @@ internal class RequestFormatTests {
       APIController(
         "super_cool_test_key",
         "gemini-pro-1.5",
-        RequestOptions(timeout = 5.seconds, endpoint = "https://my.custom.endpoint"),
+        RequestOptions(
+          timeout = 5.seconds,
+          endpoint = "https://my.custom.endpoint",
+          apiVersion = "v1beta"
+        ),
         mockEngine,
         TEST_CLIENT_ID,
         null,
@@ -138,6 +145,36 @@ internal class RequestFormatTests {
     mockEngine.requestHistory.first().url.host shouldBe "my.custom.endpoint"
   }
 
+  @Test
+  fun `using custom API version`() = doBlocking {
+    val channel = ByteChannel(autoFlush = true)
+    val mockEngine = MockEngine {
+      respond(channel, HttpStatusCode.OK, headersOf(HttpHeaders.ContentType, "application/json"))
+    }
+    prepareStreamingResponse(createResponses("Random")).forEach { channel.writeFully(it) }
+    val controller =
+      APIController(
+        "super_cool_test_key",
+        "gemini-pro-1.5",
+        RequestOptions(timeoutInMillis = 5.seconds.inWholeMilliseconds, apiVersion = ApiVersion.V1),
+        mockEngine,
+        TEST_CLIENT_ID,
+        null,
+      )
+
+    withTimeout(5.seconds) {
+      controller.generateContentStream(textGenerateContentRequest("cats")).collect {
+        it.candidates?.isEmpty() shouldBe false
+        channel.close()
+      }
+    }
+
+    mockEngine.requestHistory.first().url.encodedPath shouldStartWith "/${ApiVersion.V1.value}"
+    // TODO: Update test to set ApiVersion.V1BETA when ApiVersion.V1 becomes the default and delete
+    // the following check.
+    RequestOptions().apiVersion shouldNotBe ApiVersion.V1.value
+  }
+
   @Test
   fun `client id header is set correctly in the request`() = doBlocking {
     val response = JSON.encodeToString(CountTokensResponse(totalTokens = 10))
diff --git a/firebase-vertexai/src/test/java/com/google/firebase/vertexai/type/RequestOptionsTests.kt b/firebase-vertexai/src/test/java/com/google/firebase/vertexai/type/RequestOptionsTests.kt
new file mode 100644
index 00000000000..6480703b150
--- /dev/null
+++ b/firebase-vertexai/src/test/java/com/google/firebase/vertexai/type/RequestOptionsTests.kt
@@ -0,0 +1,86 @@
+/*
+ * Copyright 2025 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.google.firebase.vertexai.type
+
+import com.google.firebase.vertexai.type.RequestOptions.Companion.DEFAULT_API_VERSION
+import com.google.firebase.vertexai.type.RequestOptions.Companion.DEFAULT_ENDPOINT
+import com.google.firebase.vertexai.type.RequestOptions.Companion.DEFAULT_TIMEOUT_IN_MILLIS
+import io.kotest.matchers.equals.shouldBeEqual
+import kotlin.time.DurationUnit
+import kotlin.time.toDuration
+import org.junit.Test
+
+internal class RequestOptionsTests {
+  private val defaultTimeout = DEFAULT_TIMEOUT_IN_MILLIS.toDuration(DurationUnit.MILLISECONDS)
+
+  @Test
+  fun `init default values`() {
+    val requestOptions = RequestOptions()
+
+    requestOptions.timeout shouldBeEqual defaultTimeout
+    requestOptions.endpoint shouldBeEqual DEFAULT_ENDPOINT
+    requestOptions.apiVersion shouldBeEqual DEFAULT_API_VERSION.value
+  }
+
+  @Test
+  fun `init custom timeout`() {
+    val expectedTimeoutInMillis = 60_000L
+
+    val requestOptions = RequestOptions(timeoutInMillis = expectedTimeoutInMillis)
+
+    requestOptions.timeout shouldBeEqual
+      expectedTimeoutInMillis.toDuration(DurationUnit.MILLISECONDS)
+    requestOptions.endpoint shouldBeEqual DEFAULT_ENDPOINT
+    requestOptions.apiVersion shouldBeEqual DEFAULT_API_VERSION.value
+  }
+
+  @Test
+  fun `init API version v1`() {
+    val expectedApiVersion = ApiVersion.V1
+
+    val requestOptions = RequestOptions(apiVersion = expectedApiVersion)
+
+    requestOptions.timeout shouldBeEqual defaultTimeout
+    requestOptions.endpoint shouldBeEqual DEFAULT_ENDPOINT
+    requestOptions.apiVersion shouldBeEqual expectedApiVersion.value
+  }
+
+  @Test
+  fun `init API version v1beta`() {
+    val expectedApiVersion = ApiVersion.V1BETA
+
+    val requestOptions = RequestOptions(apiVersion = expectedApiVersion)
+
+    requestOptions.timeout shouldBeEqual defaultTimeout
+    requestOptions.endpoint shouldBeEqual DEFAULT_ENDPOINT
+    requestOptions.apiVersion shouldBeEqual expectedApiVersion.value
+  }
+
+  @Test
+  fun `init all public options`() {
+    val expectedTimeoutInMillis = 30_000L
+    val expectedApiVersion = ApiVersion.V1BETA
+
+    val requestOptions =
+      RequestOptions(timeoutInMillis = expectedTimeoutInMillis, apiVersion = expectedApiVersion)
+
+    requestOptions.timeout shouldBeEqual
+      expectedTimeoutInMillis.toDuration(DurationUnit.MILLISECONDS)
+    requestOptions.endpoint shouldBeEqual DEFAULT_ENDPOINT
+    requestOptions.apiVersion shouldBeEqual expectedApiVersion.value
+  }
+}
diff --git a/firebase-vertexai/update_responses.sh b/firebase-vertexai/update_responses.sh
index b13b94c8229..cb01e1a2c40 100755
--- a/firebase-vertexai/update_responses.sh
+++ b/firebase-vertexai/update_responses.sh
@@ -17,7 +17,7 @@
 # This script replaces mock response files for Vertex AI unit tests with a fresh
 # clone of the shared repository of Vertex AI test data.
 
-RESPONSES_VERSION='v3.*' # The major version of mock responses to use
+RESPONSES_VERSION='v5.*' # The major version of mock responses to use
 REPO_NAME="vertexai-sdk-test-data"
 REPO_LINK="https://github.com/FirebaseExtended/$REPO_NAME.git"