diff --git a/src/adapter/aws-lambda/client.test.ts b/src/adapter/aws-lambda/client.test.ts
new file mode 100644
index 000000000..d852a965f
--- /dev/null
+++ b/src/adapter/aws-lambda/client.test.ts
@@ -0,0 +1,113 @@
+/* eslint-disable @typescript-eslint/no-unused-vars */
+
+import { HttpResponse, http } from 'msw'
+import { setupServer } from 'msw/node'
+import { expect, beforeAll, afterAll, afterEach, describe, it } from 'vitest'
+import { Hono } from '../../hono'
+import { hlc, calculateSHA256 } from './client'
+
+const app = new Hono()
+  .post('/hash-check', async (c) => {
+    const payload = await c.req.json()
+    const sha256 = c.req.header('x-amz-content-sha256')
+    return c.json({ receivedHash: sha256, payload }, 200)
+  })
+  .put('/hash-check', async (c) => {
+    const payload = await c.req.json()
+    const sha256 = c.req.header('x-amz-content-sha256')
+    return c.json({ receivedHash: sha256, payload }, 200)
+  })
+
+const server = setupServer(
+  http.post('http://localhost/hash-check', async ({ request }) => {
+    const sha256 = request.headers.get('x-amz-content-sha256')
+    const payload = await request.json()
+
+    const expectedHash = await calculateSHA256(JSON.stringify(payload))
+
+    if (sha256 === expectedHash) {
+      return HttpResponse.json({ result: 'ok', receivedHash: sha256, payload })
+    } else {
+      return HttpResponse.json(
+        { result: 'mismatch', receivedHash: sha256, expectedHash },
+        { status: 400 }
+      )
+    }
+  }),
+
+  http.put('http://localhost/hash-check', async ({ request }) => {
+    const sha256 = request.headers.get('x-amz-content-sha256')
+    const payload = await request.json()
+
+    const expectedHash = await calculateSHA256(JSON.stringify(payload))
+    if (sha256 === expectedHash) {
+      return HttpResponse.json({ result: 'ok', receivedHash: sha256, payload })
+    } else {
+      return HttpResponse.json(
+        { result: 'mismatch', receivedHash: sha256, expectedHash },
+        { status: 400 }
+      )
+    }
+  })
+)
+
+beforeAll(() => server.listen())
+afterEach(() => server.resetHandlers())
+afterAll(() => server.close())
+
+describe('x-amz-content-sha256 header tests', () => {
+  type AppType = typeof app
+  const client = hlc<AppType>('http://localhost')
+
+  it('Should send correct x-amz-content-sha256 header on POST', async () => {
+    const payload = { name: 'Alice', message: 'Hello World' }
+    const res = await client['hash-check'].$post({ json: payload })
+    expect(res.ok).toBe(true)
+    const data = await res.json()
+    expect(data.payload).toEqual(payload)
+    expect(data.receivedHash).toBeDefined()
+
+    const expectedHash = await calculateSHA256(JSON.stringify(payload))
+    expect(data.receivedHash).toBe(expectedHash)
+  })
+
+  it('Should send correct x-amz-content-sha256 header on PUT', async () => {
+    const payload = { user: 'Bob', comment: 'This is a test' }
+    const res = await client['hash-check'].$put({ json: payload })
+    expect(res.ok).toBe(true)
+    const data = await res.json()
+    expect(data.payload).toEqual(payload)
+    expect(data.receivedHash).toBeDefined()
+
+    const calculateSHA256 = async (message: string): Promise<string> => {
+      const msgBuffer = new TextEncoder().encode(message)
+      const hashBuffer = await crypto.subtle.digest('SHA-256', msgBuffer)
+      const hashBytes = new Uint8Array(hashBuffer)
+      let hashHex = ''
+      for (let i = 0; i < hashBytes.length; i++) {
+        const b = hashBytes[i]
+        hashHex += b < 16 ? '0' + b.toString(16) : b.toString(16)
+      }
+      return hashHex
+    }
+
+    const expectedHash = await calculateSHA256(JSON.stringify(payload))
+    expect(data.receivedHash).toBe(expectedHash)
+  })
+
+  it('Should fail if no JSON is provided on POST (no hash)', async () => {
+    const res = await client['hash-check'].$post()
+    expect(res.ok).toBe(false)
+    expect(res.status).toBe(500)
+    const data = await res.json()
+    expect(data.receivedHash).toBeUndefined()
+  })
+
+  it('Should fail if no JSON is provided on PUT (no hash)', async () => {
+    const res = await client['hash-check'].$put()
+    expect(res.ok).toBe(false)
+    expect(res.status).toBe(500)
+    const data = await res.json()
+    expect(data.receivedHash).toBeUndefined()
+  })
+})
diff --git a/src/adapter/aws-lambda/client.ts b/src/adapter/aws-lambda/client.ts
new file mode 100644
index 000000000..6c5a855db
--- /dev/null
+++ b/src/adapter/aws-lambda/client.ts
@@ -0,0 +1,209 @@
+import { createProxy } from '../../client/client'
+import type { Client, ClientRequestOptions } from '../../client/types'
+import {
+  buildSearchParams,
+  deepMerge,
+  mergePath,
+  removeIndexString,
+  replaceUrlParam,
+  replaceUrlProtocol,
+} from '../../client/utils'
+import type { Hono } from '../../hono'
+import type { FormValue, ValidationTargets } from '../../types'
+import { serialize } from '../../utils/cookie'
+import type { UnionToIntersection } from '../../utils/types'
+
+export const calculateSHA256 = async (message: string): Promise<string> => {
+  const msgBuffer = new TextEncoder().encode(message)
+  const hashBuffer = await crypto.subtle.digest('SHA-256', msgBuffer)
+  const hashBytes = new Uint8Array(hashBuffer)
+
+  let hashHex = ''
+  for (let i = 0; i < hashBytes.length; i++) {
+    const b = hashBytes[i]
+    hashHex += b < 16 ? '0' + b.toString(16) : b.toString(16)
+  }
+
+  return hashHex
+}
+
+class LambdaClientRequestImpl {
+  private url: string
+  private method: string
+  private queryParams: URLSearchParams | undefined = undefined
+  private pathParams: Record<string, string> = {}
+  private rBody: BodyInit | undefined
+  private cType: string | undefined = undefined
+
+  constructor(url: string, method: string) {
+    this.url = url
+    this.method = method
+  }
+  fetch = async (
+    args?: ValidationTargets<FormValue> & {
+      param?: Record<string, string>
+    },
+    opt?: ClientRequestOptions
+  ) => {
+    if (args) {
+      if (args.query) {
+        this.queryParams = buildSearchParams(args.query)
+      }
+
+      if (args.form) {
+        const form = new FormData()
+        for (const [k, v] of Object.entries(args.form)) {
+          if (Array.isArray(v)) {
+            for (const v2 of v) {
+              form.append(k, v2)
+            }
+          } else {
+            form.append(k, v)
+          }
+        }
+        this.rBody = form
+      }
+
+      if (args.json) {
+        this.rBody = JSON.stringify(args.json)
+        this.cType = 'application/json'
+      }
+
+      if (args.param) {
+        this.pathParams = args.param
+      }
+    }
+
+    let methodUpperCase = this.method.toUpperCase()
+
+    const headerValues: Record<string, string> = {
+      ...args?.header,
+      ...(typeof opt?.headers === 'function' ? await opt.headers() : opt?.headers),
+    }
+
+    if (args?.cookie) {
+      const cookies: string[] = []
+      for (const [key, value] of Object.entries(args.cookie)) {
+        cookies.push(serialize(key, value, { path: '/' }))
+      }
+      headerValues['Cookie'] = cookies.join(',')
+    }
+
+    if (this.cType) {
+      headerValues['Content-Type'] = this.cType
+    }
+
+    if (
+      (methodUpperCase === 'POST' || methodUpperCase === 'PUT') &&
+      this.rBody &&
+      typeof this.rBody === 'string'
+    ) {
+      const hash = await calculateSHA256(this.rBody)
+      headerValues['x-amz-content-sha256'] = hash
+    }
+
+    const headers = new Headers(headerValues ?? undefined)
+    let url = this.url
+
+    url = removeIndexString(url)
+    url = replaceUrlParam(url, this.pathParams)
+
+    if (this.queryParams) {
+      url = url + '?' + this.queryParams.toString()
+    }
+    methodUpperCase = this.method.toUpperCase()
+    const setBody = !(methodUpperCase === 'GET' || methodUpperCase === 'HEAD')
+
+    return (opt?.fetch || fetch)(url, {
+      body: setBody ? this.rBody : undefined,
+      method: methodUpperCase,
+      headers: headers,
+      ...opt?.init,
+    })
+  }
+}
+
+// eslint-disable-next-line @typescript-eslint/no-explicit-any
+export const hlc = <T extends Hono<any, any, any>>(
+  baseUrl: string,
+  options?: ClientRequestOptions
+) =>
+  createProxy(function proxyCallback(opts) {
+    const parts = [...opts.path]
+
+    // allow calling .toString() and .valueOf() on the proxy
+    if (parts.at(-1) === 'toString') {
+      if (parts.at(-2) === 'name') {
+        // e.g. hc().somePath.name.toString() -> "somePath"
+        return parts.at(-3) || ''
+      }
+      // e.g. hc().somePath.toString()
+      return proxyCallback.toString()
+    }
+
+    if (parts.at(-1) === 'valueOf') {
+      if (parts.at(-2) === 'name') {
+        // e.g. hc().somePath.name.valueOf() -> "somePath"
+        return parts.at(-3) || ''
+      }
+      // e.g. hc().somePath.valueOf()
+      return proxyCallback
+    }
+
+    let method = ''
+    if (/^\$/.test(parts.at(-1) as string)) {
+      const last = parts.pop()
+      if (last) {
+        method = last.replace(/^\$/, '')
+      }
+    }
+
+    const path = parts.join('/')
+    const url = mergePath(baseUrl, path)
+    if (method === 'url') {
+      let result = url
+      if (opts.args[0]) {
+        if (opts.args[0].param) {
+          result = replaceUrlParam(url, opts.args[0].param)
+        }
+        if (opts.args[0].query) {
+          result = result + '?' + buildSearchParams(opts.args[0].query).toString()
+        }
+      }
+      return new URL(result)
+    }
+    if (method === 'ws') {
+      const webSocketUrl = replaceUrlProtocol(
+        opts.args[0] && opts.args[0].param ? replaceUrlParam(url, opts.args[0].param) : url,
+        'ws'
+      )
+      const targetUrl = new URL(webSocketUrl)
+
+      const queryParams: Record<string, string | string[]> | undefined = opts.args[0]?.query
+      if (queryParams) {
+        Object.entries(queryParams).forEach(([key, value]) => {
+          if (Array.isArray(value)) {
+            value.forEach((item) => targetUrl.searchParams.append(key, item))
+          } else {
+            targetUrl.searchParams.set(key, value)
+          }
+        })
+      }
+      const establishWebSocket = (...args: ConstructorParameters<typeof WebSocket>) => {
+        if (options?.webSocket !== undefined && typeof options.webSocket === 'function') {
+          return options.webSocket(...args)
+        }
+        return new WebSocket(...args)
+      }
+
+      return establishWebSocket(targetUrl.toString())
+    }
+
+    const req = new LambdaClientRequestImpl(url, method)
+    if (method) {
+      options ??= {}
+      const args = deepMerge<ClientRequestOptions>(options, { ...opts.args[1] })
+      return req.fetch(opts.args[0], args)
+    }
+    return req
+  }, []) as UnionToIntersection<Client<T>>
diff --git a/src/adapter/aws-lambda/index.ts b/src/adapter/aws-lambda/index.ts
index 74d0a09ad..add124614 100644
--- a/src/adapter/aws-lambda/index.ts
+++ b/src/adapter/aws-lambda/index.ts
@@ -4,6 +4,7 @@
  */
 
 export { handle, streamHandle } from './handler'
+export { hlc } from './client'
 export type { APIGatewayProxyResult, LambdaEvent } from './handler'
 export type {
   ApiGatewayRequestContext,
diff --git a/src/client/client.ts b/src/client/client.ts
index 95f3a6fd0..48e964741 100644
--- a/src/client/client.ts
+++ b/src/client/client.ts
@@ -12,7 +12,7 @@ import {
   replaceUrlProtocol,
 } from './utils'
 
-const createProxy = (callback: Callback, path: string[]) => {
+export const createProxy = (callback: Callback, path: string[]) => {
   const proxy: unknown = new Proxy(() => {}, {
     get(_obj, key) {
       if (typeof key !== 'string' || key === 'then') {