diff --git a/packages/element-web-module-api/src/api.test.ts b/packages/element-web-module-api/src/api.test.ts
index f68200f122..62dd3973aa 100644
--- a/packages/element-web-module-api/src/api.test.ts
+++ b/packages/element-web-module-api/src/api.test.ts
@@ -7,15 +7,14 @@ Please see LICENSE files in the repository root for full details.
 
 import { expect, test } from "vitest";
 
-import { Api, isModule } from "./api.js";
+import { Api } from ".";
+import { isModule } from "./api.js";
 
 const TestModule = {
     default: class TestModule {
         public static moduleApiVersion = "1.0.0";
         public constructor(private readonly api: Api) {}
-        public async load(): Promise<void> {
-            console.log("TestModule loaded");
-        }
+        public async load(): Promise<void> {}
     },
 };
 
diff --git a/packages/element-web-module-api/src/loader.spec.ts b/packages/element-web-module-api/src/loader.spec.ts
new file mode 100644
index 0000000000..85270cce38
--- /dev/null
+++ b/packages/element-web-module-api/src/loader.spec.ts
@@ -0,0 +1,58 @@
+/*
+Copyright 2025 New Vector Ltd.
+
+SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial
+Please see LICENSE files in the repository root for full details.
+*/
+
+import { expect, test, describe, vi, beforeEach, afterEach } from "vitest";
+
+import { Api, ModuleIncompatibleError, ModuleLoader } from ".";
+
+describe("ModuleIncompatibleError", () => {
+    test("should extend Error", () => {
+        expect(new ModuleIncompatibleError("1.0.0")).toBeInstanceOf(Error);
+    });
+});
+
+describe("ModuleLoader", () => {
+    const mockApi = {} as Api;
+
+    beforeEach(() => {
+        vi.stubGlobal("__VERSION__", "1.0.1");
+    });
+
+    test("should load a module", async () => {
+        const TestModule = {
+            default: class TestModule {
+                public static moduleApiVersion = "^1.0.0";
+                public constructor(private readonly api: Api) {}
+                public async load(): Promise<void> {}
+            },
+        };
+
+        const spy = vi.spyOn(TestModule.default.prototype, "load");
+
+        const loader = new ModuleLoader(mockApi);
+        await loader.load(TestModule);
+        await loader.start();
+        expect(spy).toHaveBeenCalledWith();
+    });
+
+    test("should fail to load an incompatible module", async () => {
+        const TestModule = {
+            default: class TestModule {
+                public static moduleApiVersion = "^2";
+                public constructor(private readonly api: Api) {}
+                public async load(): Promise<void> {}
+            },
+        };
+
+        const spy = vi.spyOn(TestModule.default.prototype, "load");
+
+        const loader = new ModuleLoader(mockApi);
+        await expect(loader.load(TestModule)).rejects.toThrowError(ModuleIncompatibleError);
+        await loader.start();
+        expect(spy).not.toHaveBeenCalledWith();
+    });
+});