diff --git a/packages/types/package.json b/packages/types/package.json
index 8274c1ce74..e8117fff37 100644
--- a/packages/types/package.json
+++ b/packages/types/package.json
@@ -31,7 +31,9 @@
   },
   "dependencies": {},
   "devDependencies": {
-    "@backstage/cli": "^0.7.11"
+    "@backstage/cli": "^0.7.11",
+    "@types/zen-observable": "^0.8.0",
+    "zen-observable": "^0.8.15"
   },
   "files": [
     "dist"
diff --git a/packages/types/src/json.test.ts b/packages/types/src/json.test.ts
new file mode 100644
index 0000000000..7da0ef8a3e
--- /dev/null
+++ b/packages/types/src/json.test.ts
@@ -0,0 +1,81 @@
+/*
+ * Copyright 2021 The Backstage Authors
+ *
+ * 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.
+ */
+
+import { JsonPrimitive, JsonArray, JsonObject, JsonValue } from './json';
+
+describe('json', () => {
+  it('JsonPrimitive', () => {
+    function isValid(..._v: JsonPrimitive[]) {}
+    isValid(1, 's', true, false, null);
+
+    // @ts-expect-error
+    const v1: JsonPrimitive = [];
+    // @ts-expect-error
+    const v2: JsonPrimitive = {};
+
+    expect(true).toBe(true);
+  });
+
+  it('JsonArray', () => {
+    function isValid(..._v: JsonArray[]) {}
+    isValid([], [1, 's', true, false, null, {}, []]);
+
+    // @ts-expect-error
+    const v1: JsonArray = 1;
+    // @ts-expect-error
+    const v2: JsonArray = 's';
+    // @ts-expect-error
+    const v3: JsonArray = true;
+    // @ts-expect-error
+    const v4: JsonArray = false;
+    // @ts-expect-error
+    const v5: JsonArray = null;
+    // @ts-expect-error
+    const v6: JsonArray = {};
+
+    expect(true).toBe(true);
+  });
+
+  it('JsonObject', () => {
+    function isValid(..._v: JsonObject[]) {}
+    isValid(
+      {},
+      { v1: 1, v2: 's', v3: true, v4: false, v5: null, v6: {}, v7: [] },
+    );
+
+    // @ts-expect-error
+    const v1: JsonObject = 1;
+    // @ts-expect-error
+    const v2: JsonObject = 's';
+    // @ts-expect-error
+    const v3: JsonObject = true;
+    // @ts-expect-error
+    const v4: JsonObject = false;
+    // @ts-expect-error
+    const v5: JsonObject = null;
+    // @ts-expect-error
+    const v6: JsonObject = [];
+
+    expect(true).toBe(true);
+  });
+
+  it('JsonValue', () => {
+    function isValid(..._v: JsonValue[]) {}
+    isValid(1, 's', true, false, null, {}, []);
+
+    expect(true).toBe(true);
+  });
+});
diff --git a/packages/types/src/observable.test.ts b/packages/types/src/observable.test.ts
new file mode 100644
index 0000000000..77cd074fa3
--- /dev/null
+++ b/packages/types/src/observable.test.ts
@@ -0,0 +1,42 @@
+/*
+ * Copyright 2021 The Backstage Authors
+ *
+ * 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.
+ */
+
+import ZenObservable from 'zen-observable';
+import { Observable, Observer, Subscription } from './observable';
+
+describe('observable', () => {
+  it('works in conjunction with zen-observables', () => {
+    // Use ZenObservable as the concrete implementation, but use our types in
+    // all other possible places in the code
+    const observable: Observable<string> = new ZenObservable<string>(
+      (subscriber: Observer<string>) => {
+        subscriber.next!('a');
+        subscriber.error!(new Error('e'));
+        subscriber.complete!();
+      },
+    );
+
+    const subscription: Subscription = observable.subscribe(
+      _value => {},
+      _error => {},
+      () => {},
+    );
+
+    subscription.unsubscribe();
+
+    expect(true).toBe(true);
+  });
+});