diff --git a/.gitignore b/.gitignore
index 0f8678b..e3a2287 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,2 +1,3 @@
 node_modules/
 *.wasm
+!docs/**/*.wasm
diff --git a/index.js b/index.js
index acecf71..b01628b 100644
--- a/index.js
+++ b/index.js
@@ -1,16 +1,36 @@
-self.wasmhttp = {
-  Serve: async (wasm) => {
-    const go = new Go()
-    const { instance } = await WebAssembly.instantiateStreaming(fetch(wasm), go.importObject)
-    try {
-        await go.run(instance)
-    } catch (e) {
-        console.error(e)
-    }
+let nextHandlerId = 1
+const handlerResolvers = {}
 
-    addEventListener('fetch', async e => {
-      if (new URL(e.request.url).pathname !== '/test') return
-      e.respondWith((await fetchHandler)(e.request))
-    })
+const startWasm = async (wasm, WASMHTTP_HANDLER_ID, WASMHTTP_BASE) => {
+  const go = new Go()
+  go.env = {
+    WASMHTTP_HANDLER_ID,
+    WASMHTTP_BASE,
   }
+  const { instance } = await WebAssembly.instantiateStreaming(fetch(wasm), go.importObject)
+  return go.run(instance)
+}
+
+self.wasmhttp = {
+  serve: async ({ wasm, base } = {
+    base: '',
+  }) => {
+    try {
+      if (!wasm) throw TypeError('option.wasm must be defined')
+
+      const handlerId = `${nextHandlerId++}`
+      const handler = new Promise(resolve => handlerResolvers[handlerId] = resolve)
+
+      startWasm(wasm, handlerId, base)
+
+      addEventListener('fetch', async e => e.respondWith((await handler)(e.request)))
+    } catch (e) {
+      console.error('wasmhttp: error:', e)
+    }
+  },
+
+  registerHandler: (handlerId, handler) => {
+    handlerResolvers[handlerId](handler)
+    delete handlerResolvers[handlerId]
+  },
 }
diff --git a/serve.go b/serve.go
index 6ed985b..b967dd8 100644
--- a/serve.go
+++ b/serve.go
@@ -55,7 +55,7 @@ func Serve(handler http.Handler) func() {
 		return res.Value()
 	})
 
-	js.Global().Get("wasmhttp").Call("RegisterHandler", os.Getenv("WASMHTTP_HANDLER_ID"), cb)
+	js.Global().Get("wasmhttp").Call("registerHandler", os.Getenv("WASMHTTP_HANDLER_ID"), cb)
 
 	return cb.Release
 }