diff --git a/.github/scripts/compare-packages-size.js b/.github/scripts/compare-packages-size.js
new file mode 100644
index 0000000..172b39e
--- /dev/null
+++ b/.github/scripts/compare-packages-size.js
@@ -0,0 +1,60 @@
+import path from "node:path";
+import { execSync as exec } from "node:child_process";
+import { statSync as stat, existsSync as exists } from "node:fs";
+import { globSync as glob } from "glob";
+
+function size(file) {
+    return exists(file) ? stat(file).size : null;
+}
+
+function format(bytes) {
+    if (bytes == null) {
+        return "—";
+    }
+
+    return bytes >= 1024
+        ? `${(bytes / 1024).toFixed(2)} KB`
+        : `${bytes} B`;
+}
+
+function delta(a, b) {
+    if (a == null || b == null) {
+        return null;
+    }
+    return a - b;
+}
+
+function icon(d) {
+    if (d == null) {
+        return "—";
+    }
+
+    if (d > 0) return "⬆️";
+    if (d < 0) return "⬇️";
+    return "➡️";
+}
+
+const pr_files = glob("dist/**/*.min.js");
+const pr_sizes = Object.fromEntries(pr_files.map(f => [f, size(f)]));
+
+exec("git fetch origin main", { stdio: "inherit" });
+exec("git checkout origin/main", { stdio: "ignore" });
+exec("npm ci --include=dev", { stdio: "inherit" });
+exec("npm run build", { stdio: "inherit" });
+
+const main_sizes = Object.fromEntries(pr_files.map(f => [f, size(f)]));
+
+let md = `
+### 📦 Bundle size comparison
+
+| Name | main | PR | Δ |
+|------|------|----|---|
+`;
+
+for (const file of pr_files) {
+    const d = delta(pr_sizes[file], main_sizes[file]);
+
+    md += `| \`${path.basename(file)}\` | ${format(main_sizes[file])} | ${format(pr_sizes[file])} | ${icon(d)} ${format(d)} |\n`;
+}
+
+console.log(md);
diff --git a/.github/workflows/pr-diff-size.yml b/.github/workflows/pr-diff-size.yml
new file mode 100644
index 0000000..691562d
--- /dev/null
+++ b/.github/workflows/pr-diff-size.yml
@@ -0,0 +1,76 @@
+name: Packages size analysis
+
+on:
+  pull_request:
+    branches: [main]
+    types: [opened, synchronize, reopened, ready_for_review]
+
+permissions:
+  contents: read
+  pull-requests: write
+  actions: read
+
+jobs:
+  analyze:
+    if: github.repository == 'rameel/ramstack.alpinegear.js'
+
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Setup Node.js
+        uses: actions/setup-node@v4
+        with:
+          node-version: '24'
+          registry-url: 'https://registry.npmjs.org'
+
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Install Dependencies
+        run: npm ci
+
+      - name: Build
+        run: npm run build
+        env:
+          NODE_ENV: production
+          SKIP_GIT_TAG_RESOLUTION: true
+
+      - name: Run size comparison
+        run: npm run size-diff-report > comment.md
+        env:
+          NODE_ENV: production
+          SKIP_GIT_TAG_RESOLUTION: true
+
+      - name: Comment PR
+        uses: actions/github-script@v7
+        with:
+          script: |
+            const fs = require('fs');
+            const body = fs.readFileSync('./comment.md', 'utf8');
+            const pr_number = context.payload.workflow_run.pull_requests[0].number;
+
+            const { data: comments } = await github.rest.issues.listComments({
+              owner: context.repo.owner,
+              repo: context.repo.repo,
+              issue_number: pr_number
+            });
+
+            const marker = "### 📦 Bundle size comparison";
+            const existing_comment = comments.find(c => c.body.includes(marker));
+
+            if (existing_comment) {
+              await github.rest.issues.updateComment({
+                owner: context.repo.owner,
+                repo: context.repo.repo,
+                comment_id: existing_comment.id,
+                body: body
+              });
+            }
+            else {
+              github.rest.issues.createComment({
+                issue_number: context.issue.number,
+                owner: context.repo.owner,
+                repo: context.repo.repo,
+                body: body
+              })
+            }
diff --git a/gulpfile.js b/gulpfile.js
index bb8c1a5..97429c6 100644
--- a/gulpfile.js
+++ b/gulpfile.js
@@ -9,13 +9,14 @@ import { rimraf } from "rimraf";
 import { rollup } from "rollup";
 
 const is_production = process.env.NODE_ENV === "production";
+const skip_git_tag_resolution = process.env.SKIP_GIT_TAG_RESOLUTION === "true";
 
 const task_delete = create_task("delete -> delete build folders", () => {
     return rimraf(["dist", "coverage", "docs/public/js"]);
 });
 
 const task_update_packages = create_task("update -> update version", async done => {
-    if (is_production) {
+    if (is_production && !skip_git_tag_resolution) {
         const current_version = await obtain_version_from_tag();
 
         const update_version = data => {
diff --git a/package.json b/package.json
index 33e7095..a18dfaa 100644
--- a/package.json
+++ b/package.json
@@ -25,6 +25,7 @@
   "scripts": {
     "build": "cross-env NODE_ENV=production gulp build",
     "build:debug": "gulp build",
+    "size-diff-report": "node .github/scripts/compare-packages-size.js",
     "test": "gulp build && vitest run && playwright test",
     "test:playwright": "playwright test",
     "test:vitest": "vitest run"