diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
index ab074369..0f74e0a0 100644
--- a/.github/workflows/release.yml
+++ b/.github/workflows/release.yml
@@ -32,31 +32,22 @@ jobs:
           fi
 
       - name: Publish mqtt5-protocol to crates.io
-        run: cargo publish --package mqtt5-protocol || echo "Version already published, skipping"
+        run: scripts/publish-crate.sh mqtt5-protocol
         env:
           CARGO_REGISTRY_TOKEN: ${{ secrets.CARGO_REGISTRY_TOKEN }}
 
-      - name: Wait for crates.io to update
-        run: sleep 30
-
       - name: Publish mqtt5 library to crates.io
-        run: cargo publish --package mqtt5 || echo "Version already published, skipping"
+        run: scripts/publish-crate.sh mqtt5
         env:
           CARGO_REGISTRY_TOKEN: ${{ secrets.CARGO_REGISTRY_TOKEN }}
 
-      - name: Wait for crates.io to update
-        run: sleep 30
-
       - name: Publish mqtt5-wasm to crates.io
-        run: cargo publish --package mqtt5-wasm || echo "Version already published, skipping"
+        run: scripts/publish-crate.sh mqtt5-wasm
         env:
           CARGO_REGISTRY_TOKEN: ${{ secrets.CARGO_REGISTRY_TOKEN }}
 
-      - name: Wait for crates.io to update
-        run: sleep 30
-
       - name: Publish mqttv5-cli to crates.io
-        run: cargo publish --package mqttv5-cli || echo "Version already published, skipping"
+        run: scripts/publish-crate.sh mqttv5-cli
         env:
           CARGO_REGISTRY_TOKEN: ${{ secrets.CARGO_REGISTRY_TOKEN }}
 
diff --git a/scripts/publish-crate.sh b/scripts/publish-crate.sh
new file mode 100755
index 00000000..1bf1f9b2
--- /dev/null
+++ b/scripts/publish-crate.sh
@@ -0,0 +1,59 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+package="$1"
+wait_secs=600
+
+version=$(cargo metadata --no-deps --format-version 1 \
+  | jq -r --arg p "$package" '.packages[] | select(.name == $p) | .version')
+if [ -z "$version" ]; then
+  echo "package $package not found in the workspace" >&2
+  exit 1
+fi
+
+index_url="https://index.crates.io/${package:0:2}/${package:2:2}/$package"
+entries=$(mktemp)
+trap 'rm -f "$entries"' EXIT
+
+index_status() {
+  local code
+  code=$(curl -s --connect-timeout 10 --max-time 30 \
+    -A "LabOverWire/mqtt-lib release workflow" \
+    -o "$entries" -w '%{http_code}' "$index_url") || code="curl exit $?"
+  case $code in
+    200)
+      if grep -qF "\"vers\":\"$version\"" "$entries"; then
+        echo listed
+      else
+        echo absent
+      fi
+      ;;
+    404) echo absent ;;
+    *) echo "unreachable ($code)" ;;
+  esac
+}
+
+wait_for_index() {
+  local wanted=$1 deadline=$((SECONDS + wait_secs)) status
+  status=$(index_status)
+  until [ "$status" = listed ] || { [ "$wanted" = known ] && [ "$status" = absent ]; }; do
+    if [ "$SECONDS" -ge "$deadline" ]; then
+      echo "$package $version: crates.io index still $status after ${wait_secs}s" >&2
+      exit 1
+    fi
+    sleep 10
+    status=$(index_status)
+  done
+  echo "$status"
+}
+
+state=$(wait_for_index known)
+if [ "$state" = listed ]; then
+  echo "$package $version is already on crates.io, skipping"
+  exit 0
+fi
+
+cargo publish --package "$package"
+
+wait_for_index listed > /dev/null
+echo "$package $version is on crates.io"