diff --git a/src/App.tsx b/src/App.tsx
index 6a73749..9721c84 100644
--- a/src/App.tsx
+++ b/src/App.tsx
@@ -23,7 +23,10 @@ import {
   isJSONRPCResult,
   ResultDispatcher,
   type JSONRPC,
-} from "./serviceworker/services.js";
+} from "./serviceworker/workerrpc.js";
+import {
+  Service
+} from "./serviceworker/services.js"
 import { makeEventListener } from "@solid-primitives/event-listener";
 import { ServiceWorkerProvider } from "./platform/host.js";
 
@@ -75,7 +78,7 @@ const App: Component = () => {
     worker: ServiceWorker,
     expectedAge: number,
   ) => {
-    const [call, ret] = dispatcher.createTypedCall("ping", undefined);
+    const [call, ret] = dispatcher.createTypedCall<Service>("ping");
     worker.postMessage(await call);
     const result = await ret;
     console.assert(!result.error, result);
diff --git a/src/serviceworker/main.ts b/src/serviceworker/main.ts
index 457875e..71a4f37 100644
--- a/src/serviceworker/main.ts
+++ b/src/serviceworker/main.ts
@@ -1,17 +1,17 @@
 import { cleanupOutdatedCaches, precacheAndRoute } from "workbox-precaching";
 import { clientsClaim } from "workbox-core";
-import type { AnyCall } from "./services";
+import { dispatchCall, isJSONRPCCall, type Call } from "./workerrpc";
 
-function checkServiceWorker(
+function isServiceWorker(
   self: WorkerGlobalScope,
 ): self is ServiceWorkerGlobalScope {
   return !!(self as unknown as ServiceWorkerGlobalScope).registration;
 }
 
-if (checkServiceWorker(self)) {
+if (isServiceWorker(self)) {
   cleanupOutdatedCaches();
   precacheAndRoute(self.__WB_MANIFEST, {
-    cleanURLs: false
+    cleanURLs: false,
   });
 
   // auto update
@@ -21,15 +21,14 @@ if (checkServiceWorker(self)) {
   throw new TypeError("This entry point must be run in a service worker");
 }
 
-self.addEventListener("message", (event: MessageEvent<AnyCall>) => {
-  if (event.data.method === "ping") {
-    event.source.postMessage({id: event.data.id, jsonrpc: "2.0", result: undefined})
-  } else {
-    event.source.postMessage({
-      error: {
-        code: -32601,
-        message: "Method not found"
-      }
-    })
+export const Service = {
+  ping() {},
+};
+
+self.addEventListener("message", (event: MessageEvent<unknown>) => {
+  const payload = event.data;
+  if (typeof payload !== "object") return;
+  if (isJSONRPCCall(payload as Record<string, unknown>)) {
+    dispatchCall(Service, event as MessageEvent<Call<unknown>>);
   }
-})
+});
diff --git a/src/serviceworker/services.ts b/src/serviceworker/services.ts
index 61f70ec..2db3d4a 100644
--- a/src/serviceworker/services.ts
+++ b/src/serviceworker/services.ts
@@ -1,177 +1,3 @@
-export type JSONRPC = {
-  jsonrpc: "2.0";
-  id?: string | number;
+export type Service = {
+  ping(): void
 };
-
-export type Call<T = undefined> = JSONRPC & {
-  method: string;
-  params: T;
-};
-
-export type RemoteError<E = undefined> = { data: E } & (
-  | {
-      code: number;
-      message: string;
-    }
-  | {
-      code: -32700;
-      message: "Parse Error";
-    }
-  | {
-      code: -32600;
-      message: "Invalid Request";
-    }
-  | {
-      code: -32601;
-      message: "Method not found";
-    }
-  | {
-      code: -32602;
-      message: "Invalid params";
-    }
-  | {
-      code: -32603;
-      message: "Internal error";
-    }
-);
-
-export type Result<T, E> = JSONRPC & { id: string | number } & (
-    | {
-        result: T;
-        error: undefined;
-      }
-    | { error: RemoteError<E>; result: undefined }
-  );
-
-export function isJSONRPCResult(
-  object: Record<string, unknown>,
-): object is Result<unknown, unknown> {
-  return object["jsonrpc"] === "2.0" && object["id"] && !object["method"];
-}
-
-export function isJSONRPCCall(
-  object: Record<string, unknown>,
-): object is Call<unknown> {
-  return object["jsonrpc"] === "2.0" && !!object["method"];
-}
-
-export class ResultDispatcher {
-  private map: Map<
-    number | string,
-    ((value: Result<unknown, unknown>) => void) | true // `true` = a call is generated, but the promise not created
-  >;
-  private nextId: number = Number.MIN_SAFE_INTEGER;
-
-  constructor() {
-    this.map = new Map();
-  }
-
-  private rollId() {
-    let id = 0;
-    while (this.map.get((id = this.nextId++))) {
-      if (this.nextId >= Number.MAX_SAFE_INTEGER) {
-        this.nextId = Number.MIN_SAFE_INTEGER;
-      }
-    }
-    return id;
-  }
-
-  createCall<T>(
-    method: string,
-    params: T,
-  ): [Promise<Call<T>>, Promise<Result<unknown, unknown>>] {
-    const id = this.rollId();
-    const p = new Promise<Result<unknown, unknown>>((resolve) =>
-      this.map.set(id, resolve),
-    );
-    this.map.set(id, true);
-    const call: Call<T> = {
-      jsonrpc: "2.0",
-      id,
-      method,
-      params,
-    };
-
-    return [
-      new Promise((resolve) => {
-        const waitUntilTheIdSet = () => {
-          // We must do this check to make sure the id is set before the call made.
-          // or the dispatching may lost the callback
-          if (this.map.get(id)) {
-            resolve(call);
-          } else {
-            setTimeout(waitUntilTheIdSet, 0);
-          }
-        };
-
-        waitUntilTheIdSet();
-      }),
-      p,
-    ];
-  }
-
-  dispatch(id: string | number, message: Result<unknown, unknown>) {
-    {
-      const callback = this.map.get(id);
-      if (!callback) return;
-      if (typeof callback !== "boolean") {
-        callback(message);
-        this.map.delete(id);
-        return Promise.resolve();
-      }
-    }
-
-    return new Promise<void>((resolve) => {
-      let retried = 0;
-
-      const checkAndDispatch = () => {
-        const callback = this.map.get(id);
-        if (typeof callback !== "boolean") {
-          callback(message);
-          this.map.delete(id);
-          resolve();
-          return;
-        }
-        setTimeout(checkAndDispatch, 0);
-        if (++retried > 3) {
-          console.warn(
-            `retried ${retried} time(s) but the callback is still disappeared, id is "${id}"`,
-          );
-        }
-      };
-
-      // start the loop
-      checkAndDispatch();
-    });
-  }
-
-  createTypedCall<
-    K extends keyof RequestParams,
-    P extends RequestParams[K],
-    R extends ResponseResults[K],
-    E extends ResponseErrorDatas[K],
-  >(method: K, params: P): [Promise<Call<P>>, Promise<Result<R, E>>] {
-    return this.createCall(method, params) as [
-      Promise<Call<P>>,
-      Promise<Result<R, E>>,
-    ];
-  }
-}
-
-interface RequestParams {
-  ping: void;
-}
-
-interface ResponseResults {
-  ping: void;
-}
-
-interface ResponseErrorDatas {
-  [key: string]: void;
-}
-
-export type AnyCall<K extends keyof RequestParams = keyof RequestParams> =
-  JSONRPC & {
-    method: K;
-    params: RequestParams[K];
-  };
diff --git a/src/serviceworker/workerrpc.ts b/src/serviceworker/workerrpc.ts
new file mode 100644
index 0000000..84bb39f
--- /dev/null
+++ b/src/serviceworker/workerrpc.ts
@@ -0,0 +1,214 @@
+export type JSONRPC = {
+  jsonrpc: "2.0";
+  id?: string | number;
+};
+
+export type Call<T = undefined> = JSONRPC & {
+  method: string;
+  params: T;
+};
+
+export type RemoteError<E = undefined> = { data: E } & (
+  | {
+      code: number;
+      message: string;
+    }
+  | {
+      code: -32700;
+      message: "Parse Error";
+    }
+  | {
+      code: -32600;
+      message: "Invalid Request";
+    }
+  | {
+      code: -32601;
+      message: "Method not found";
+    }
+  | {
+      code: -32602;
+      message: "Invalid params";
+    }
+  | {
+      code: -32603;
+      message: "Internal error";
+    }
+);
+
+export type Result<T, E> = JSONRPC & { id: string | number } & (
+    | {
+        result: T;
+        error: undefined;
+      }
+    | { error: RemoteError<E>; result: undefined }
+  );
+
+export function isJSONRPCResult(
+  object: Record<string, unknown>,
+): object is Result<unknown, unknown> {
+  return object["jsonrpc"] === "2.0" && object["id"] && !object["method"];
+}
+
+export function isJSONRPCCall(
+  object: Record<string, unknown>,
+): object is Call<unknown> {
+  return object["jsonrpc"] === "2.0" && !!object["method"];
+}
+
+export class ResultDispatcher {
+  private map: Map<
+    number | string,
+    ((value: Result<unknown, unknown>) => void) | true // `true` = a call is generated, but the promise not created
+  >;
+  private nextId: number = Number.MIN_SAFE_INTEGER;
+
+  constructor() {
+    this.map = new Map();
+  }
+
+  private rollId() {
+    let id = 0;
+    while (this.map.get((id = this.nextId++))) {
+      if (this.nextId >= Number.MAX_SAFE_INTEGER) {
+        this.nextId = Number.MIN_SAFE_INTEGER;
+      }
+    }
+    return id;
+  }
+
+  createCall<T>(
+    method: string,
+    params: T,
+  ): [Promise<Call<T>>, Promise<Result<unknown, unknown>>] {
+    const id = this.rollId();
+    const p = new Promise<Result<unknown, unknown>>((resolve) =>
+      this.map.set(id, resolve),
+    );
+    this.map.set(id, true);
+    const call: Call<T> = {
+      jsonrpc: "2.0",
+      id,
+      method,
+      params,
+    };
+
+    return [
+      new Promise((resolve) => {
+        const waitUntilTheIdSet = () => {
+          // We must do this check to make sure the id is set before the call made.
+          // or the dispatching may lost the callback
+          if (this.map.get(id)) {
+            resolve(call);
+          } else {
+            setTimeout(waitUntilTheIdSet, 0);
+          }
+        };
+
+        waitUntilTheIdSet();
+      }),
+      p,
+    ];
+  }
+
+  dispatch(id: string | number, message: Result<unknown, unknown>) {
+    {
+      const callback = this.map.get(id);
+      if (!callback) return;
+      if (typeof callback !== "boolean") {
+        callback(message);
+        this.map.delete(id);
+        return Promise.resolve();
+      }
+    }
+
+    return new Promise<void>((resolve) => {
+      let retried = 0;
+
+      const checkAndDispatch = () => {
+        const callback = this.map.get(id);
+        if (typeof callback !== "boolean") {
+          callback(message);
+          this.map.delete(id);
+          resolve();
+          return;
+        }
+        setTimeout(checkAndDispatch, 0);
+        if (++retried > 3) {
+          console.warn(
+            `retried ${retried} time(s) but the callback is still disappeared, id is "${id}"`,
+          );
+        }
+      };
+
+      // start the loop
+      checkAndDispatch();
+    });
+  }
+
+  createTypedCall<
+    S extends AnyService,
+    E = unknown,
+    K extends keyof S = keyof S,
+    P extends Parameters<S[K]> = Parameters<S[K]>,
+    R extends ReturnType<S[K]> = ReturnType<S[K]>,
+  >(method: K, ...params: P): [Promise<Call<P>>, Promise<Result<R, E>>] {
+    return this.createCall(method as string, params) as [
+      Promise<Call<P>>,
+      Promise<Result<R, E>>,
+    ];
+  }
+}
+
+type AnyService = Record<string, ((...args: unknown[]) => unknown) | undefined>
+
+export async function dispatchCall<
+  S extends AnyService,
+>(service: S, event: MessageEvent<Call<unknown>>) {
+  try {
+    const fn = service[event.data.method];
+    if (!fn) {
+      if (event.data.id)
+        return event.source.postMessage({
+          jsonrpc: "2.0",
+          id: event.data.id,
+          error: {
+            code: -30601,
+            message: "Method not found",
+          },
+        } as Result<void, void>);
+    }
+
+    try {
+      const result = await fn(...event.data.params as unknown[]);
+
+      if (!event.data.id) return;
+
+      event.source.postMessage({
+        jsonrpc: "2.0",
+        id: event.data.id,
+        result: result,
+      } as Result<unknown, void>);
+    } catch (reason) {
+      event.source.postMessage({
+        jsonrpc: "2.0",
+        id: event.data.id,
+        error: {
+          code: 0,
+          message: String(reason),
+          data: reason,
+        },
+      } as Result<unknown, unknown>);
+    }
+  } catch (reason) {
+    if (event.data.id)
+      event.source.postMessage({
+        jsonrpc: "2.0",
+        id: event.data.id,
+        error: {
+          code: -32603,
+          message: "Internal error",
+          data: reason,
+        },
+      } as Result<void, unknown>);
+  }
+}