diff --git a/cli/setup-project.js b/cli/setup-project.js
index a1fcad9d3..f79bfb02c 100755
--- a/cli/setup-project.js
+++ b/cli/setup-project.js
@@ -54,8 +54,12 @@ const updateProjectConfig = async (projectName) => {
   const contents = fs.readFileSync(configPath, {
     encoding: 'utf-8',
   });
+  // Schemes first, lowercase only. /ObytesApp/gi also matches `obytesapp`
+  // and would copy PascalCase from the project name (breaks EAS Update).
+  const scheme = projectName.toLowerCase().replace(/[^a-z0-9+.-]/g, '');
   const replaced = contents
-    .replace(/ObytesApp/gi, projectName)
+    .replace(/obytesapp/g, scheme)
+    .replace(/ObytesApp/g, projectName)
     .replace(/com.obytes/gi, `com.${projectName.toLowerCase()}`)
     .replace(/obytes/gi, 'expo-owner');
 
diff --git a/docs/src/assets/eas-update-scheme-validation-error.png b/docs/src/assets/eas-update-scheme-validation-error.png
new file mode 100644
index 000000000..db46a5bdb
Binary files /dev/null and b/docs/src/assets/eas-update-scheme-validation-error.png differ
diff --git a/env.ts b/env.ts
index 9c3024cbf..3402637b6 100644
--- a/env.ts
+++ b/env.ts
@@ -6,7 +6,7 @@ import packageJSON from './package.json';
 const envSchema = z.object({
   EXPO_PUBLIC_APP_ENV: z.enum(['development', 'preview', 'production']),
   EXPO_PUBLIC_NAME: z.string(),
-  EXPO_PUBLIC_SCHEME: z.string(),
+  EXPO_PUBLIC_SCHEME: z.string().regex(/^[a-z][a-z0-9+.-]*$/),
   EXPO_PUBLIC_BUNDLE_ID: z.string(),
   EXPO_PUBLIC_PACKAGE: z.string(),
   EXPO_PUBLIC_VERSION: z.string(),
@@ -35,10 +35,13 @@ const PACKAGES = {
   production: 'com.obytes',
 } as const;
 
+// URL schemes must be lowercase. EAS Update rejects PascalCase
+// (e.g. obytesApp) with: scheme must match ^[a-z][a-z0-9+.-]*$.
+// Display NAME can stay mixed-case.
 const SCHEMES = {
-  development: 'obytesApp',
-  preview: 'obytesApp.preview',
-  production: 'obytesApp',
+  development: 'obytesapp',
+  preview: 'obytesapp.preview',
+  production: 'obytesapp',
 } as const;
 
 const NAME = 'ObytesApp';