diff --git a/frontend_server_client/CHANGELOG.md b/frontend_server_client/CHANGELOG.md
index c14926832..d263fd075 100644
--- a/frontend_server_client/CHANGELOG.md
+++ b/frontend_server_client/CHANGELOG.md
@@ -1,3 +1,8 @@
+## 3.1.0
+
+- Add `additionalSources` parameter to `FrontendServerClient`, for passing
+  additional `--source`s to the kernel compiler.
+
 ## 3.0.0
 
 - Update the `compile` api to return a non-null `CompileResult`, and instead
diff --git a/frontend_server_client/lib/src/frontend_server_client.dart b/frontend_server_client/lib/src/frontend_server_client.dart
index 69735ba11..a183270ed 100644
--- a/frontend_server_client/lib/src/frontend_server_client.dart
+++ b/frontend_server_client/lib/src/frontend_server_client.dart
@@ -57,6 +57,7 @@ class FrontendServerClient {
     String target = 'vm', // The kernel target type.
     bool verbose = false, // Verbose logs, including server/client messages
     bool printIncrementalDependencies = true,
+    List<String> additionalSources = const [],
   }) async {
     var feServer = await Process.start(Platform.resolvedExecutable, [
       if (debug) '--observe',
@@ -80,6 +81,10 @@ class FrontendServerClient {
       if (enabledExperiments != null)
         for (var experiment in enabledExperiments)
           '--enable-experiment=$experiment',
+      for (var source in additionalSources) ...[
+        '--source',
+        source,
+      ],
     ]);
     var feServerStdoutLines = StreamQueue(feServer.stdout
         .transform(utf8.decoder)
diff --git a/frontend_server_client/pubspec.yaml b/frontend_server_client/pubspec.yaml
index 9fe3aef56..e010afa97 100644
--- a/frontend_server_client/pubspec.yaml
+++ b/frontend_server_client/pubspec.yaml
@@ -1,5 +1,5 @@
 name: frontend_server_client
-version: 3.0.0
+version: 3.1.0
 description: >-
   Client code to start and interact with the frontend_server compiler from the
   Dart SDK.