diff --git a/packages/web/index.html b/packages/web/index.html
index 89b5378..375e11d 100644
--- a/packages/web/index.html
+++ b/packages/web/index.html
@@ -15,16 +15,49 @@
       content="Find the gear tooth counts for a watch complication — moon phase, calendar, world time — and see exactly how accurate each train is. Runs entirely in your browser."
     />
     <meta property="og:url" content="https://notadev99.github.io/Involute/" />
-    <meta name="twitter:card" content="summary" />
+    <meta property="og:image" content="https://notadev99.github.io/Involute/og.png" />
+    <meta property="og:image:type" content="image/png" />
+    <meta property="og:image:width" content="1200" />
+    <meta property="og:image:height" content="630" />
+    <meta
+      property="og:image:alt"
+      content="Involute — a moon-phase gear train (6:45 · 8:63), computed exactly: about 1 day slow in 122 years."
+    />
+    <meta name="twitter:card" content="summary_large_image" />
     <meta name="twitter:title" content="Involute — gear-train calculator for watchmakers" />
     <meta
       name="twitter:description"
       content="Find the gear tooth counts for a watch complication and see how accurate each train is. Exact rational math, in your browser."
     />
+    <meta name="twitter:image" content="https://notadev99.github.io/Involute/og.png" />
+    <link rel="canonical" href="https://notadev99.github.io/Involute/" />
     <link
       rel="icon"
       href="data:image/svg+xml,%3Csvg%20xmlns='http://www.w3.org/2000/svg'%20viewBox='0%200%2032%2032'%3E%3Cg%20fill='none'%20stroke='%239a6a1c'%20stroke-width='2'%3E%3Cpath%20d='M16%203v4M16%2025v4M29%2016h-4M7%2016H3M25.2%206.8l-2.8%202.8M9.6%2022.4l-2.8%202.8M25.2%2025.2l-2.8-2.8M9.6%209.6L6.8%206.8'/%3E%3Ccircle%20cx='16'%20cy='16'%20r='7'/%3E%3Ccircle%20cx='16'%20cy='16'%20r='2.5'/%3E%3C/g%3E%3C/svg%3E"
     />
+    <script type="application/ld+json">
+      {
+        "@context": "https://schema.org",
+        "@type": "SoftwareApplication",
+        "name": "Involute",
+        "url": "https://notadev99.github.io/Involute/",
+        "applicationCategory": "UtilitiesApplication",
+        "operatingSystem": "Any (web browser)",
+        "browserRequirements": "Requires JavaScript.",
+        "description": "A precise gear-train calculator for watchmaking. Give it a target ratio or a real-world period and it computes the tooth counts that hit it, the exact residual error, and a schematic of the train — entirely in the browser, from exact rational arithmetic.",
+        "featureList": [
+          "Solve gear trains for astronomical complications: moon phase, calendar, world time",
+          "Exact rational and continued-fraction approximation with the residual error stated",
+          "Going-train solver from beat rate and escape-wheel teeth",
+          "Client-side computation, shareable permalink, CSV and JSON export"
+        ],
+        "offers": { "@type": "Offer", "price": "0", "priceCurrency": "USD" },
+        "isAccessibleForFree": true,
+        "license": "https://opensource.org/licenses/MIT",
+        "codeRepository": "https://github.com/notadev99/Involute",
+        "author": { "@type": "Person", "name": "Thomas Brenas", "url": "https://github.com/notadev99" }
+      }
+    </script>
   </head>
   <body><main id="app"></main><script type="module" src="/src/main.ts"></script></body>
 </html>
diff --git a/packages/web/public/og.png b/packages/web/public/og.png
new file mode 100644
index 0000000..d90fef9
Binary files /dev/null and b/packages/web/public/og.png differ
