diff --git a/Cargo.lock b/Cargo.lock
index 31fab04d58..504cb2a573 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -5137,6 +5137,7 @@ dependencies = [
  "async-trait",
  "client",
  "collections",
+ "criterion",
  "ctor",
  "dap",
  "env_logger 0.11.8",
@@ -5153,6 +5154,7 @@ dependencies = [
  "parking_lot",
  "paths",
  "project",
+ "rand 0.8.5",
  "release_channel",
  "remote",
  "reqwest_client",
@@ -17533,6 +17535,7 @@ dependencies = [
  "postcard",
  "psm",
  "pulley-interpreter",
+ "rayon",
  "rustix 0.38.44",
  "semver",
  "serde",
diff --git a/Cargo.toml b/Cargo.toml
index 65bcec73bf..cf227b8394 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -430,6 +430,7 @@ convert_case = "0.8.0"
 core-foundation = "0.10.0"
 core-foundation-sys = "0.8.6"
 core-video = { version = "0.4.3", features = ["metal"] }
+criterion = { version = "0.5", features = ["html_reports"] }
 ctor = "0.4.0"
 dap-types = { git = "https://github.com/zed-industries/dap-types", rev = "be69a016ba710191b9fdded28c8b042af4b617f7" }
 dashmap = "6.0"
@@ -608,6 +609,7 @@ wasmtime = { version = "29", default-features = false, features = [
     "runtime",
     "cranelift",
     "component-model",
+    "parallel-compilation",
 ] }
 wasmtime-wasi = "29"
 which = "6.0.0"
diff --git a/crates/extension/src/extension_builder.rs b/crates/extension/src/extension_builder.rs
index 34bf30363a..73152c667b 100644
--- a/crates/extension/src/extension_builder.rs
+++ b/crates/extension/src/extension_builder.rs
@@ -398,7 +398,7 @@ impl ExtensionBuilder {
 
     async fn install_wasi_sdk_if_needed(&self) -> Result<PathBuf> {
         let url = if let Some(asset_name) = WASI_SDK_ASSET_NAME {
-            format!("{WASI_SDK_URL}/{asset_name}")
+            format!("{WASI_SDK_URL}{asset_name}")
         } else {
             bail!("wasi-sdk is not available for platform {}", env::consts::OS);
         };
diff --git a/crates/extension/src/extension_manifest.rs b/crates/extension/src/extension_manifest.rs
index 799b30861f..6ddaee98ba 100644
--- a/crates/extension/src/extension_manifest.rs
+++ b/crates/extension/src/extension_manifest.rs
@@ -162,7 +162,7 @@ pub struct GrammarManifestEntry {
     pub path: Option<String>,
 }
 
-#[derive(Clone, PartialEq, Eq, Debug, Deserialize, Serialize)]
+#[derive(Clone, Default, PartialEq, Eq, Debug, Deserialize, Serialize)]
 pub struct LanguageServerManifestEntry {
     /// Deprecated in favor of `languages`.
     #[serde(default)]
diff --git a/crates/extension_host/Cargo.toml b/crates/extension_host/Cargo.toml
index 5ce6e1991f..dbee29f36c 100644
--- a/crates/extension_host/Cargo.toml
+++ b/crates/extension_host/Cargo.toml
@@ -54,6 +54,7 @@ wasmtime.workspace = true
 workspace-hack.workspace = true
 
 [dev-dependencies]
+criterion.workspace = true
 ctor.workspace = true
 env_logger.workspace = true
 fs = { workspace = true, features = ["test-support"] }
@@ -62,6 +63,11 @@ language = { workspace = true, features = ["test-support"] }
 language_extension.workspace = true
 parking_lot.workspace = true
 project = { workspace = true, features = ["test-support"] }
+rand.workspace = true
 reqwest_client.workspace = true
 theme = { workspace = true, features = ["test-support"] }
 theme_extension.workspace = true
+
+[[bench]]
+name = "extension_compilation_benchmark"
+harness = false
diff --git a/crates/extension_host/benches/extension_compilation_benchmark.rs b/crates/extension_host/benches/extension_compilation_benchmark.rs
new file mode 100644
index 0000000000..2837557528
--- /dev/null
+++ b/crates/extension_host/benches/extension_compilation_benchmark.rs
@@ -0,0 +1,145 @@
+use std::{collections::BTreeMap, path::PathBuf, sync::Arc};
+
+use criterion::{BatchSize, BenchmarkId, Criterion, criterion_group, criterion_main};
+use extension::{
+    ExtensionCapability, ExtensionHostProxy, ExtensionLibraryKind, ExtensionManifest,
+    LanguageServerManifestEntry, LibManifestEntry, SchemaVersion,
+    extension_builder::{CompileExtensionOptions, ExtensionBuilder},
+};
+use extension_host::wasm_host::WasmHost;
+use fs::RealFs;
+use gpui::{SemanticVersion, TestAppContext, TestDispatcher};
+use http_client::{FakeHttpClient, Response};
+use node_runtime::NodeRuntime;
+use rand::{SeedableRng, rngs::StdRng};
+use reqwest_client::ReqwestClient;
+use serde_json::json;
+use settings::SettingsStore;
+use util::test::TempTree;
+
+fn extension_benchmarks(c: &mut Criterion) {
+    let cx = init();
+
+    let mut group = c.benchmark_group("load");
+
+    let mut manifest = manifest();
+    let wasm_bytes = wasm_bytes(&cx, &mut manifest);
+    let manifest = Arc::new(manifest);
+    let extensions_dir = TempTree::new(json!({
+        "installed": {},
+        "work": {}
+    }));
+    let wasm_host = wasm_host(&cx, &extensions_dir);
+
+    group.bench_function(BenchmarkId::from_parameter(1), |b| {
+        b.iter_batched(
+            || wasm_bytes.clone(),
+            |wasm_bytes| {
+                let _extension = cx
+                    .executor()
+                    .block(wasm_host.load_extension(wasm_bytes, &manifest, cx.executor()))
+                    .unwrap();
+            },
+            BatchSize::SmallInput,
+        );
+    });
+}
+
+fn init() -> TestAppContext {
+    const SEED: u64 = 9999;
+    let dispatcher = TestDispatcher::new(StdRng::seed_from_u64(SEED));
+    let cx = TestAppContext::build(dispatcher, None);
+    cx.executor().allow_parking();
+    cx.update(|cx| {
+        let store = SettingsStore::test(cx);
+        cx.set_global(store);
+        release_channel::init(SemanticVersion::default(), cx);
+    });
+
+    cx
+}
+
+fn wasm_bytes(cx: &TestAppContext, manifest: &mut ExtensionManifest) -> Vec<u8> {
+    let extension_builder = extension_builder();
+    let path = PathBuf::from(env!("CARGO_MANIFEST_DIR"))
+        .parent()
+        .unwrap()
+        .parent()
+        .unwrap()
+        .join("extensions/test-extension");
+    cx.executor()
+        .block(extension_builder.compile_extension(
+            &path,
+            manifest,
+            CompileExtensionOptions { release: true },
+        ))
+        .unwrap();
+    std::fs::read(path.join("extension.wasm")).unwrap()
+}
+
+fn extension_builder() -> ExtensionBuilder {
+    let user_agent = format!(
+        "Zed Extension CLI/{} ({}; {})",
+        env!("CARGO_PKG_VERSION"),
+        std::env::consts::OS,
+        std::env::consts::ARCH
+    );
+    let http_client = Arc::new(ReqwestClient::user_agent(&user_agent).unwrap());
+    // Local dir so that we don't have to download it on every run
+    let build_dir = PathBuf::from(env!("CARGO_MANIFEST_DIR")).join("benches/.build");
+    ExtensionBuilder::new(http_client, build_dir)
+}
+
+fn wasm_host(cx: &TestAppContext, extensions_dir: &TempTree) -> Arc<WasmHost> {
+    let http_client = FakeHttpClient::create(async |_| {
+        Ok(Response::builder().status(404).body("not found".into())?)
+    });
+    let extensions_dir = extensions_dir.path().canonicalize().unwrap();
+    let work_dir = extensions_dir.join("work");
+    let fs = Arc::new(RealFs::new(None, cx.executor()));
+
+    cx.update(|cx| {
+        WasmHost::new(
+            fs,
+            http_client,
+            NodeRuntime::unavailable(),
+            Arc::new(ExtensionHostProxy::new()),
+            work_dir,
+            cx,
+        )
+    })
+}
+
+fn manifest() -> ExtensionManifest {
+    ExtensionManifest {
+        id: "test-extension".into(),
+        name: "Test Extension".into(),
+        version: "0.1.0".into(),
+        schema_version: SchemaVersion(1),
+        description: Some("An extension for use in tests.".into()),
+        authors: Vec::new(),
+        repository: None,
+        themes: Default::default(),
+        icon_themes: Vec::new(),
+        lib: LibManifestEntry {
+            kind: Some(ExtensionLibraryKind::Rust),
+            version: Some(SemanticVersion::new(0, 1, 0)),
+        },
+        languages: Vec::new(),
+        grammars: BTreeMap::default(),
+        language_servers: [("gleam".into(), LanguageServerManifestEntry::default())]
+            .into_iter()
+            .collect(),
+        context_servers: BTreeMap::default(),
+        slash_commands: BTreeMap::default(),
+        indexed_docs_providers: BTreeMap::default(),
+        snippets: None,
+        capabilities: vec![ExtensionCapability::ProcessExec {
+            command: "echo".into(),
+            args: vec!["hello!".into()],
+        }],
+    }
+}
+
+criterion_group!(benches, extension_benchmarks);
+criterion_main!(benches);
diff --git a/crates/rope/Cargo.toml b/crates/rope/Cargo.toml
index 5adadfd39d..d9714a23ae 100644
--- a/crates/rope/Cargo.toml
+++ b/crates/rope/Cargo.toml
@@ -27,7 +27,7 @@ env_logger.workspace = true
 gpui = { workspace = true, features = ["test-support"] }
 rand.workspace = true
 util = { workspace = true, features = ["test-support"] }
-criterion = { version = "0.5", features = ["html_reports"] }
+criterion.workspace = true
 
 [[bench]]
 name = "rope_benchmark"
diff --git a/tooling/workspace-hack/Cargo.toml b/tooling/workspace-hack/Cargo.toml
index f656d6a00b..ec99a7e681 100644
--- a/tooling/workspace-hack/Cargo.toml
+++ b/tooling/workspace-hack/Cargo.toml
@@ -132,7 +132,7 @@ url = { version = "2", features = ["serde"] }
 uuid = { version = "1", features = ["serde", "v4", "v5", "v7"] }
 wasm-encoder = { version = "0.221", features = ["wasmparser"] }
 wasmparser = { version = "0.221" }
-wasmtime = { version = "29", default-features = false, features = ["async", "component-model", "cranelift", "demangle", "gc-drc"] }
+wasmtime = { version = "29", default-features = false, features = ["async", "component-model", "cranelift", "demangle", "gc-drc", "parallel-compilation"] }
 wasmtime-cranelift = { version = "29", default-features = false, features = ["component-model", "gc-drc"] }
 wasmtime-environ = { version = "29", default-features = false, features = ["compile", "component-model", "demangle", "gc-drc"] }
 winnow = { version = "0.7", features = ["simd"] }
@@ -267,7 +267,7 @@ url = { version = "2", features = ["serde"] }
 uuid = { version = "1", features = ["serde", "v4", "v5", "v7"] }
 wasm-encoder = { version = "0.221", features = ["wasmparser"] }
 wasmparser = { version = "0.221" }
-wasmtime = { version = "29", default-features = false, features = ["async", "component-model", "cranelift", "demangle", "gc-drc"] }
+wasmtime = { version = "29", default-features = false, features = ["async", "component-model", "cranelift", "demangle", "gc-drc", "parallel-compilation"] }
 wasmtime-cranelift = { version = "29", default-features = false, features = ["component-model", "gc-drc"] }
 wasmtime-environ = { version = "29", default-features = false, features = ["compile", "component-model", "demangle", "gc-drc"] }
 winnow = { version = "0.7", features = ["simd"] }