diff --git a/.github/workflows/npm-publish.yml b/.github/workflows/npm-publish.yml
index 05e2d7cf..ef074941 100644
--- a/.github/workflows/npm-publish.yml
+++ b/.github/workflows/npm-publish.yml
@@ -79,10 +79,14 @@ jobs:
           cp magic/magic.js  npm/
           cp magic/magic.wasm npm/
 
-      - name: Set package version from tag
-        if: startsWith(github.ref, 'refs/tags/v')
+      - name: Set package version
         run: |
-          VERSION="${GITHUB_REF#refs/tags/v}"
+          base=$(cat VERSION)                              # e.g. 8.3.637
+          date=$(git show -s --format=%cs | tr -d '-')    # e.g. 20260414
+          hash=$(git show -s --format=%h)                 # e.g. d157eea
+          # npm requires semver; use pre-release syntax as the closest equivalent
+          # to the AppImage form 8.3.637~20260414~d157eea
+          VERSION="${base}-${date}.${hash}"
           cd npm
           npm version "$VERSION" --no-git-tag-version
 
diff --git a/npm/package.json b/npm/package.json
index 0b43ce76..d4a82e17 100644
--- a/npm/package.json
+++ b/npm/package.json
@@ -1,6 +1,6 @@
 {
   "name": "magic-vlsi-wasm",
-  "version": "8.3.637",
+  "version": "0.0.0-dev",
   "description": "Magic VLSI Layout Tool — headless WebAssembly build",
   "type": "module",
   "main": "index.js",