diff --git a/src/services/options/OptionsProvider.ts b/src/services/options/OptionsProvider.ts
new file mode 100644
index 0000000..2e64156
--- /dev/null
+++ b/src/services/options/OptionsProvider.ts
@@ -0,0 +1,31 @@
+import { OptionsConfiguration } from '../../common/options/OptionsConfiguration';
+import {
+  OptionCodename,
+  OptionsValues,
+} from '../../common/options/optionsPrototype';
+
+export interface OptionsProviderPort {
+  /**
+   * Returns the value of option |option|.
+   */
+  getOptionValue<O extends OptionCodename>(
+    option: O,
+  ): Promise<OptionsValues[O]>;
+
+  /**
+   * Returns whether |feature| is enabled.
+   */
+  isEnabled(option: OptionCodename): Promise<boolean>;
+
+  getOptionsValues(): Promise<OptionsValues>;
+
+  /**
+   * Adds a listener for changes in the options configuration.
+   */
+  addListener(listener: OptionsChangeListener): void;
+}
+
+export type OptionsChangeListener = (
+  previousOptionValues: OptionsConfiguration,
+  currentOptionValues: OptionsConfiguration,
+) => void;