diff --git a/.changeset/fix-unsupported-script-types.md b/.changeset/fix-unsupported-script-types.md
new file mode 100644
index 000000000000..9d412fe1cd55
--- /dev/null
+++ b/.changeset/fix-unsupported-script-types.md
@@ -0,0 +1,5 @@
+---
+"@biomejs/biome": patch
+---
+
+Fixed [#9506](https://github.com/biomejs/biome/issues/9506) and [#9479](https://github.com/biomejs/biome/issues/9479): Biome no longer reports false parse errors on `<script type="speculationrules">` and `<script type="application/ld+json">` tags. These script types contain non-JavaScript content and are now correctly skipped by the embedded language detector.
diff --git a/crates/biome_service/src/embed/registry.rs b/crates/biome_service/src/embed/registry.rs
index 286117fd6a9c..0dfd9f56d11e 100644
--- a/crates/biome_service/src/embed/registry.rs
+++ b/crates/biome_service/src/embed/registry.rs
@@ -40,15 +40,18 @@ static HTML_DETECTORS: [EmbedDetector; 5] = [
     // <script> → JS/TS/JSON (dynamic: depends on type/lang attributes + framework)
     //
     // A single detector handles all <script> variants via the dynamic resolver:
-    //   - <script>                          → JsScript (classic HTML)
-    //   - <script type="module">            → JsModule (ES module)
-    //   - <script lang="ts">                → Ts (Vue/Svelte)
-    //   - <script lang="tsx">               → Tsx (Vue/Svelte)
-    //   - <script lang="jsx">               → Jsx (Vue/Svelte)
-    //   - <script type="importmap">         → Json
-    //   - <script type="application/json">  → Json
-    //   - Astro <script> (no frontmatter)   → Ts
-    //   - Vue/Svelte default                → JsModule
+    //   - <script>                               → JsScript (classic HTML)
+    //   - <script type="module">                 → JsModule (ES module)
+    //   - <script lang="ts">                     → Ts (Vue/Svelte)
+    //   - <script lang="tsx">                    → Tsx (Vue/Svelte)
+    //   - <script lang="jsx">                    → Jsx (Vue/Svelte)
+    //   - <script type="importmap">              → Json
+    //   - <script type="application/json">       → Json
+    //   - Astro <script> (no frontmatter)        → Ts
+    //   - Vue/Svelte default                     → JsModule
+    //   - <script type="speculationrules">       → skipped (unsupported type)
+    //   - <script type="application/ld+json">    → skipped (unsupported type)
+    //   - <script type="text/x-handlebars-*">    → skipped (unsupported type)
     //
     // The handler dispatches on embed_match.guest to call the right parser
     // (parse JS vs parse JSON). No separate detector needed for JSON scripts.
@@ -56,7 +59,10 @@ static HTML_DETECTORS: [EmbedDetector; 5] = [
         tag: "script",
         target: EmbedTarget::Dynamic {
             resolver: resolve_script_language,
-            fallback: Some(GuestLanguage::JsScript),
+            // No fallback: the resolver handles all supported cases explicitly.
+            // Returning None means "skip this element" (e.g. unsupported type
+            // like speculationrules or application/ld+json).
+            fallback: None,
         },
     },
     // <style> → CSS (dynamic: skips SCSS via resolver returning None)
diff --git a/crates/biome_service/src/workspace/server.tests.rs b/crates/biome_service/src/workspace/server.tests.rs
index ecbf00ca710a..eeb22c4e6ac6 100644
--- a/crates/biome_service/src/workspace/server.tests.rs
+++ b/crates/biome_service/src/workspace/server.tests.rs
@@ -485,6 +485,83 @@ fn pull_diagnostics_and_actions_for_js_file() {
     insta::assert_debug_snapshot!(result)
 }
 
+/// Regression test for https://github.com/biomejs/biome/issues/9506 and
+/// https://github.com/biomejs/biome/issues/9479.
+///
+/// `<script type="speculationrules">` and `<script type="application/ld+json">`
+/// contain JSON-like content that is NOT JavaScript. Before this fix, biome's
+/// embed registry fallback would treat these as JavaScript, causing false
+/// parse errors and incorrect lint diagnostics.
+#[test]
+fn no_diagnostics_for_unsupported_script_types() {
+    // speculationrules content is JSON-like but is NOT JavaScript.
+    // application/ld+json content is JSON-LD, also not JavaScript.
+    // Both should be silently skipped by the embed detector (no JS parse errors).
+    const FILE_CONTENT: &str = r#"<!doctype html>
+<html>
+  <head>
+    <script type="speculationrules">
+      {
+        "prerender": [
+          { "source": "list", "urls": ["/next-page"] }
+        ]
+      }
+    </script>
+    <script type="application/ld+json">
+      {
+        "@context": "https://schema.org",
+        "@type": "Article",
+        "headline": "Test"
+      }
+    </script>
+  </head>
+</html>"#;
+
+    let fs = MemoryFileSystem::default();
+    fs.insert(Utf8PathBuf::from("/project/file.html"), FILE_CONTENT);
+
+    let (workspace, project_key) = setup_workspace_and_open_project(fs, "/");
+
+    workspace
+        .scan_project(ScanProjectParams {
+            project_key,
+            watch: false,
+            force: false,
+            scan_kind: ScanKind::Project,
+            verbose: false,
+        })
+        .unwrap();
+
+    workspace
+        .open_file(OpenFileParams {
+            project_key,
+            path: BiomePath::new("/project/file.html"),
+            content: FileContent::FromServer,
+            document_file_source: None,
+            persist_node_cache: false,
+            inline_config: None,
+        })
+        .unwrap();
+
+    let result = workspace
+        .pull_diagnostics_and_actions(PullDiagnosticsAndActionsParams {
+            path: BiomePath::new("/project/file.html"),
+            only: vec![],
+            skip: vec![],
+            enabled_rules: vec![],
+            project_key,
+            categories: Default::default(),
+            inline_config: None,
+        })
+        .unwrap();
+
+    assert!(
+        result.diagnostics.is_empty(),
+        "Expected no diagnostics for unsupported script types, got: {:#?}",
+        result.diagnostics
+    );
+}
+
 #[test]
 fn format_js_with_embedded_css() {
     const FILE_PATH: &str = "/project/file.js";