diff --git a/.github/workflows/check.yaml b/.github/workflows/check.yaml
index 269ae3e4..3fa96e76 100644
--- a/.github/workflows/check.yaml
+++ b/.github/workflows/check.yaml
@@ -18,3 +18,15 @@ jobs:
       # https://forums.swift.org/t/warnings-as-errors-for-libraries-frameworks/58393/2
       - run: swift build -Xswiftc -warnings-as-errors
       - run: swift test
+
+  check-on-platforms:
+    runs-on: macos-latest
+    strategy:
+      matrix:
+        platform: [macOS, iOS, tvOS]
+    steps:
+      - uses: actions/checkout@v4
+      # TODO OS version, and ambiguity in platforms, and no match
+      - run: xcodebuild -list
+      - run: xcodebuild -scheme AblyChat -destination "platform=${{ matrix.platform }}"
+      - run: xcodebuild test -scheme AblyChat -destination "platform=${{ matrix.platform }}"
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 2f05361a..e985a744 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -29,3 +29,5 @@ At time of writing, the latest version of Xcode is 15.4, and the `Package.swift`
 and then we also take the minimum of these and ably-cocoa (which at time of writing were all lower than the above)
 
 TODO let's see what Xcode 16 says too though — OK, doesn’t seem any different in Beta 3
+
+TODO we probably also have to take into account which simulators are available on the version of Xcode we're using, _and_ which are installed on the GitHub runner