diff --git a/.github/workflows/publish.yaml b/.github/workflows/publish.yaml
index 67f1ea7..b643ad1 100644
--- a/.github/workflows/publish.yaml
+++ b/.github/workflows/publish.yaml
@@ -45,7 +45,7 @@ jobs:
       - run: deno publish
         working-directory: ${{ matrix.workspace }}
   npm:
-    if: fromJSON(needs.generate-matrix.outputs.exists)
+    if: ${{ fromJSON(needs.generate-matrix.outputs.exists)}}
     name: Publish ${{ matrix.name }}@${{matrix.version}} to NPM
     runs-on: ubuntu-latest
 
@@ -71,6 +71,7 @@ jobs:
       - run: deno run -A www/tasks/build-npm.ts ${{matrix.workspace}}
 
       - run: npm publish --access=public --tag=latest
+        if: ${{ matrix.npmVersionUnpublished }}
         working-directory: ${{matrix.workspace}}/build/npm
         env:
           NODE_AUTH_TOKEN: ${{secrets.NPM_TOKEN}}
diff --git a/www/hooks/use-npm-client.ts b/www/hooks/use-npm-client.ts
new file mode 100644
index 0000000..26e99f3
--- /dev/null
+++ b/www/hooks/use-npm-client.ts
@@ -0,0 +1,19 @@
+import { createContext } from "effection";
+import { Client } from "jsr:@yorganci/npm-registry-api@0.3.0";
+import { call } from "effection";
+
+const NPMClientContext = createContext("npm-client", new Client());
+
+export function* isVersionPublished(name: string, versionOrTag = "latest") {
+  const client = yield* NPMClientContext;
+
+  try {
+    yield* call(() => client.getPackageManifest(name, versionOrTag));
+    return true;
+  } catch (error) {
+    if (error instanceof Deno.errors.NotFound) {
+      return false;
+    }
+    throw error;
+  }
+}
diff --git a/www/tasks/publish-matrix.ts b/www/tasks/publish-matrix.ts
index ccebccc..b0019d3 100644
--- a/www/tasks/publish-matrix.ts
+++ b/www/tasks/publish-matrix.ts
@@ -2,6 +2,7 @@ import { call, each, main } from "effection";
 import { usePackages } from "../hooks/use-packages.ts";
 import { DenoJson } from "../hooks/use-package.tsx";
 import { x } from "../../tinyexec/mod.ts";
+import { isVersionPublished } from "../hooks/use-npm-client.ts";
 
 await main(function* () {
   let packages = yield* usePackages();
@@ -33,6 +34,8 @@ await main(function* () {
         tagname,
         name: pkg.name,
         version: pkg.version,
+        npmVersionUnpublished:
+          !(yield* isVersionPublished(pkg.name, pkg.version)),
       });
     }
   }