diff --git a/client/src/App.tsx b/client/src/App.tsx
index 25eea40d..6c3c0705 100644
--- a/client/src/App.tsx
+++ b/client/src/App.tsx
@@ -7,6 +7,7 @@ import { Menu } from './Navigation'
 import { PreferencesContext } from './Popups/Settings'
 import { useWindowDimensions } from './utils/window_width'
 import LeanLogo from './assets/logo.svg'
+import LZString from 'lz-string';
 
 import CodeMirror, { EditorView } from '@uiw/react-codemirror'
 
@@ -26,6 +27,7 @@ interface UrlArgs {
   project: string | null
   url: string | null
   code: string | null
+  codez: string | null
 }
 
 /**
@@ -286,7 +288,11 @@ function App() {
     if (args.code) {
       let _code = decodeURIComponent(args.code)
       setContent(_code)
+    } else if (args.codez) {
+      let _code = LZString.decompressFromBase64(args.codez);
+      setContent(_code);
     }
+
     if (args.url) {setUrl(decodeURIComponent(args.url))}
     if (args.project && args.project != project) {
       console.log(`[Lean4web] setting project to ${args.project}`)
@@ -320,18 +326,24 @@ function App() {
     let _project = (project == 'mathlib-demo' ? null : project)
     if (code === contentFromUrl) {
       if (url !== null) {
-        let args = {project: _project, url: encodeURIComponent(url), code: null}
+        let args = {project: _project, url: encodeURIComponent(url), code: null, codez: null}
         history.replaceState(undefined, undefined!, formatArgs(args))
       } else {
-        let args = {project: _project, url: null, code: null}
+        let args = {project: _project, url: null, code: null, codez: null}
         history.replaceState(undefined, undefined!, formatArgs(args))
       }
     } else if (code === "") {
-      let args = {project: _project, url: null, code: null}
+      let args = {project: _project, url: null, code: null, codez: null}
       history.replaceState(undefined, undefined!, formatArgs(args))
     } else {
-      let args = {project: _project, url: null, code: fixedEncodeURIComponent(code)}
-      history.replaceState(undefined, undefined!, formatArgs(args))
+      const compressed = LZString.compressToBase64(code).replace(/=*$/, '');
+      if(compressed.length < code.length) {
+        let args = {project: _project, url: null, code: null, codez: compressed}
+        history.replaceState(undefined, undefined!, formatArgs(args))
+      } else {
+        let args = {project: _project, url: null, code: fixedEncodeURIComponent(code), codez: null}
+        history.replaceState(undefined, undefined!, formatArgs(args))
+      }
     }
   }, [editor, project, code, contentFromUrl])
 
diff --git a/package-lock.json b/package-lock.json
index 692b6df4..1f16aecc 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -14,12 +14,14 @@
         "@fortawesome/react-fontawesome": "^0.2.2",
         "@mui/material": "^5.16.4",
         "@types/file-saver": "^2.0.7",
+        "@types/lz-string": "^1.5.0",
         "@uiw/react-codemirror": "^4.23.0",
         "concurrently": "^8.2.2",
         "express": "^4.19.2",
         "file-saver": "^2.0.5",
         "ip-anonymize": "^0.1.0",
         "lean4monaco": "^1.0.24",
+        "lz-string": "^1.5.0",
         "memfs": "^4.11.1",
         "nocache": "^4.0.0",
         "node": "^22.6.0",
@@ -2530,6 +2532,15 @@
       "resolved": "https://registry.npmjs.org/@types/file-saver/-/file-saver-2.0.7.tgz",
       "integrity": "sha512-dNKVfHd/jk0SkR/exKGj2ggkB45MAkzvWCaqLUUgkyjITkGNzH8H+yUwr+BLJUBjZOe9w8X3wgmXhZDRg1ED6A=="
     },
+    "node_modules/@types/lz-string": {
+      "version": "1.5.0",
+      "resolved": "https://registry.npmjs.org/@types/lz-string/-/lz-string-1.5.0.tgz",
+      "integrity": "sha512-s84fKOrzqqNCAPljhVyC5TjAo6BH4jKHw9NRNFNiRUY5QSgZCmVm5XILlWbisiKl+0OcS7eWihmKGS5akc2iQw==",
+      "deprecated": "This is a stub types definition. lz-string provides its own type definitions, so you do not need this installed.",
+      "dependencies": {
+        "lz-string": "*"
+      }
+    },
     "node_modules/@types/node": {
       "version": "22.1.0",
       "resolved": "https://registry.npmjs.org/@types/node/-/node-22.1.0.tgz",
@@ -5467,6 +5478,14 @@
         "yallist": "^3.0.2"
       }
     },
+    "node_modules/lz-string": {
+      "version": "1.5.0",
+      "resolved": "https://registry.npmjs.org/lz-string/-/lz-string-1.5.0.tgz",
+      "integrity": "sha512-h5bgJWpxJNswbU7qCrV0tIKQCaS3blPDrqKWx+QxzuzL1zGUzij9XCWLrSLsJPu5t+eWA/ycetzYAO5IOMcWAQ==",
+      "bin": {
+        "lz-string": "bin/bin.js"
+      }
+    },
     "node_modules/magic-string": {
       "version": "0.30.11",
       "resolved": "https://registry.npmjs.org/magic-string/-/magic-string-0.30.11.tgz",
diff --git a/package.json b/package.json
index 53f41ea5..c0a0f960 100644
--- a/package.json
+++ b/package.json
@@ -25,12 +25,14 @@
     "@fortawesome/react-fontawesome": "^0.2.2",
     "@mui/material": "^5.16.4",
     "@types/file-saver": "^2.0.7",
+    "@types/lz-string": "^1.5.0",
     "@uiw/react-codemirror": "^4.23.0",
     "concurrently": "^8.2.2",
     "express": "^4.19.2",
     "file-saver": "^2.0.5",
     "ip-anonymize": "^0.1.0",
     "lean4monaco": "^1.0.24",
+    "lz-string": "^1.5.0",
     "memfs": "^4.11.1",
     "nocache": "^4.0.0",
     "node": "^22.6.0",