diff --git a/.github/workflows/rust.yml b/.github/workflows/rust.yml
index 64ef82e..d696c68 100644
--- a/.github/workflows/rust.yml
+++ b/.github/workflows/rust.yml
@@ -72,3 +72,17 @@ jobs:
         uses: actions/checkout@v4
       - name: Check semver
         uses: obi1kenobi/cargo-semver-checks-action@v2
+
+  check-external-types:
+    name: Validate external types appearing in public API
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout sources
+        uses: actions/checkout@v4
+      - name: Install rust toolchain
+        uses: dtolnay/rust-toolchain@master
+        with:
+          toolchain: nightly-2024-02-07
+          # ^ sync with https://github.com/awslabs/cargo-check-external-types/blob/main/rust-toolchain.toml
+      - run: cargo install cargo-check-external-types
+      - run: cargo check-external-types
diff --git a/Cargo.toml b/Cargo.toml
index 38b7258..b8c6c58 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -51,3 +51,10 @@ hex-literal = "0.4"
 
 [badges]
 travis-ci = { repository = "rusticata/pcap-parser" }
+
+[package.metadata.cargo_check_external_types]
+allowed_external_types = [
+  "nom",
+  "nom::*",
+  "circular::Buffer",
+]