diff --git a/package.json b/package.json
index bf508c305..fd720a17a 100644
--- a/package.json
+++ b/package.json
@@ -34,7 +34,7 @@
   "scripts": {
     "test": "npm run format && npm run build && vitest run",
     "covtest": "vitest run --coverage",
-    "prettier": "prettier \"{lib,test}/**/*.ts\" \"scripts/**/*.{mjs,cjs,js}\" \"examples/**/*.{ts,js,mjs}\"",
+    "prettier": "prettier \"{lib,test,scripts,examples}/**/*.{ts,js,cjs,mjs}\"",
     "format": "npm run prettier -- --write",
     "format:check": "npm run prettier -- -l",
     "clean": "rm -rf dist/*",
diff --git a/test/consumer/consumer-contract-js.spec.ts b/test/consumer/consumer-contract-js.spec.ts
new file mode 100644
index 000000000..51f4c304d
--- /dev/null
+++ b/test/consumer/consumer-contract-js.spec.ts
@@ -0,0 +1,65 @@
+import { afterAll, beforeAll, describe, it } from "vitest";
+import {
+  buildPackedTarball,
+  copyDir,
+  installSdkTarball,
+  prepareFixtureDir,
+  removeDir,
+  runCommand,
+} from "./runner";
+
+const repoRoot = process.cwd();
+const tempDirs: string[] = [];
+let tarballPath = "";
+const JS_TIMEOUT_MS = 180_000;
+
+async function runJsFixture(
+  fixtureName: "js-esm" | "js-cjs",
+  scripts: readonly string[],
+): Promise<void> {
+  const fixtureDir = await prepareFixtureDir(tempDirs, fixtureName);
+  await copyDir(
+    `${repoRoot}/test/consumer/fixtures/${fixtureName}`,
+    fixtureDir,
+  );
+  installSdkTarball(fixtureDir, tarballPath);
+
+  for (const script of scripts) {
+    runCommand(fixtureDir, "node", [script]);
+  }
+}
+
+afterAll(async () => {
+  await Promise.allSettled(tempDirs.map(dir => removeDir(dir)));
+});
+
+describe("dual package JS consumer contract", () => {
+  beforeAll(async () => {
+    const packOutDir = await prepareFixtureDir(tempDirs, "js-pack");
+    tarballPath = await buildPackedTarball(repoRoot, packOutDir);
+  });
+
+  it(
+    "runs JS ESM fixture with resolution and behavioral contract checks",
+    async () => {
+      await runJsFixture("js-esm", [
+        "./resolution-load-check.mjs",
+        "./outbound-http-contract.mjs",
+        "./webhook-signature-contract.mjs",
+      ]);
+    },
+    JS_TIMEOUT_MS,
+  );
+
+  it(
+    "runs JS CJS fixture resolution and behavioral contract checks",
+    async () => {
+      await runJsFixture("js-cjs", [
+        "./resolution-load-check.cjs",
+        "./outbound-http-contract.cjs",
+        "./webhook-signature-contract.cjs",
+      ]);
+    },
+    JS_TIMEOUT_MS,
+  );
+});
diff --git a/test/consumer/consumer-contract-packaging.spec.ts b/test/consumer/consumer-contract-packaging.spec.ts
new file mode 100644
index 000000000..6d40b545d
--- /dev/null
+++ b/test/consumer/consumer-contract-packaging.spec.ts
@@ -0,0 +1,69 @@
+import assert from "node:assert/strict";
+import { existsSync } from "node:fs";
+import { afterAll, beforeAll, describe, it } from "vitest";
+import {
+  buildPackedTarball,
+  listTarEntries,
+  prepareFixtureDir,
+  readTarPackageJson,
+  removeDir,
+} from "./runner";
+
+const repoRoot = process.cwd();
+const tempDirs: string[] = [];
+let tarballPath = "";
+
+afterAll(async () => {
+  await Promise.allSettled(tempDirs.map(dir => removeDir(dir)));
+});
+
+describe("dual package packaging contract", () => {
+  beforeAll(async () => {
+    const packOutDir = await prepareFixtureDir(tempDirs, "packaging-pack");
+    tarballPath = await buildPackedTarball(repoRoot, packOutDir);
+    assert.equal(existsSync(tarballPath), true);
+  });
+
+  it("includes required export targets and metadata", async () => {
+    const entries = listTarEntries(repoRoot, tarballPath);
+    const requiredEntries = [
+      "package/dist/index.js",
+      "package/dist/index.d.ts",
+      "package/dist/cjs/index.js",
+      "package/dist/cjs/index.d.ts",
+      "package/dist/cjs/package.json",
+      "package/package.json",
+    ];
+
+    for (const entry of requiredEntries) {
+      assert.equal(
+        entries.includes(entry),
+        true,
+        `${entry} was not found in tarball`,
+      );
+    }
+
+    const packagedJson = await readTarPackageJson(repoRoot, tarballPath);
+    assert.equal(packagedJson.main, "./dist/cjs/index.js");
+    assert.equal(packagedJson.types, "./dist/index.d.ts");
+
+    assert.equal(packagedJson.exports["."].import.types, "./dist/index.d.ts");
+    assert.equal(packagedJson.exports["."].import.default, "./dist/index.js");
+    assert.equal(
+      packagedJson.exports["."].require.types,
+      "./dist/cjs/index.d.ts",
+    );
+    assert.equal(
+      packagedJson.exports["."].require.default,
+      "./dist/cjs/index.js",
+    );
+  });
+
+  it("does not include test artifacts", () => {
+    const entries = listTarEntries(repoRoot, tarballPath);
+    const testArtifacts = entries.filter(entry =>
+      /(^|\/)tests?\//.test(entry.replace(/^package\//, "")),
+    );
+    assert.deepEqual(testArtifacts, []);
+  });
+});
diff --git a/test/consumer/consumer-contract-ts5.spec.ts b/test/consumer/consumer-contract-ts5.spec.ts
new file mode 100644
index 000000000..47bdaa78d
--- /dev/null
+++ b/test/consumer/consumer-contract-ts5.spec.ts
@@ -0,0 +1,84 @@
+import { afterAll, beforeAll, describe, it } from "vitest";
+import { buildPackedTarball, prepareFixtureDir, removeDir } from "./runner";
+import { runTsLane } from "./runner/ts-lane";
+
+const repoRoot = process.cwd();
+const tempDirs: string[] = [];
+let tarballPath = "";
+const TS5_VERSION = "5.9.3";
+const TS_TIMEOUT_MS = 240_000;
+
+afterAll(async () => {
+  await Promise.allSettled(tempDirs.map(dir => removeDir(dir)));
+});
+
+describe("dual package TS5 consumer contract", () => {
+  beforeAll(async () => {
+    const packOutDir = await prepareFixtureDir(tempDirs, "ts5-pack");
+    tarballPath = await buildPackedTarball(repoRoot, packOutDir);
+  });
+
+  it(
+    `runs TS ESM modern lane (${TS5_VERSION})`,
+    async () => {
+      await runTsLane(
+        { repoRoot, tarballPath, tsVersion: TS5_VERSION, tempDirs },
+        {
+          fixtureName: "ts5-esm-modern",
+          packageTemplateFile: "package.module.json",
+          tsconfigTemplateFile: "tsconfig.nodenext.json",
+          withRuntime: true,
+        },
+      );
+    },
+    TS_TIMEOUT_MS,
+  );
+
+  it(
+    `runs TS CJS modern lane (${TS5_VERSION})`,
+    async () => {
+      await runTsLane(
+        { repoRoot, tarballPath, tsVersion: TS5_VERSION, tempDirs },
+        {
+          fixtureName: "ts5-cjs-modern",
+          packageTemplateFile: "package.commonjs.json",
+          tsconfigTemplateFile: "tsconfig.nodenext.json",
+          withRuntime: true,
+        },
+      );
+    },
+    TS_TIMEOUT_MS,
+  );
+
+  it(
+    `runs TS CJS legacy lane (${TS5_VERSION})`,
+    async () => {
+      await runTsLane(
+        { repoRoot, tarballPath, tsVersion: TS5_VERSION, tempDirs },
+        {
+          fixtureName: "ts5-cjs-legacy",
+          packageTemplateFile: "package.commonjs.json",
+          tsconfigTemplateFile: "tsconfig.legacy-commonjs.json",
+          withRuntime: true,
+        },
+      );
+    },
+    TS_TIMEOUT_MS,
+  );
+
+  it(
+    `runs TS bundler compile-only lane (${TS5_VERSION})`,
+    async () => {
+      await runTsLane(
+        { repoRoot, tarballPath, tsVersion: TS5_VERSION, tempDirs },
+        {
+          fixtureName: "ts5-bundler",
+          packageTemplateFile: "package.module.json",
+          tsconfigTemplateFile: "tsconfig.bundler.json",
+          withRuntime: false,
+        },
+      );
+    },
+    TS_TIMEOUT_MS,
+  );
+});
diff --git a/test/consumer/consumer-contract-ts6.spec.ts b/test/consumer/consumer-contract-ts6.spec.ts
new file mode 100644
index 000000000..4828f0b45
--- /dev/null
+++ b/test/consumer/consumer-contract-ts6.spec.ts
@@ -0,0 +1,84 @@
+import { afterAll, beforeAll, describe, it } from "vitest";
+import { buildPackedTarball, prepareFixtureDir, removeDir } from "./runner";
+import { runTsLane } from "./runner/ts-lane";
+
+const repoRoot = process.cwd();
+const tempDirs: string[] = [];
+let tarballPath = "";
+const TS6_VERSION = "6.0.3";
+const TS_TIMEOUT_MS = 240_000;
+
+afterAll(async () => {
+  await Promise.allSettled(tempDirs.map(dir => removeDir(dir)));
+});
+
+describe("dual package TS6 consumer contract", () => {
+  beforeAll(async () => {
+    const packOutDir = await prepareFixtureDir(tempDirs, "ts6-pack");
+    tarballPath = await buildPackedTarball(repoRoot, packOutDir);
+  });
+
+  it(
+    `runs TS ESM modern lane (${TS6_VERSION})`,
+    async () => {
+      await runTsLane(
+        { repoRoot, tarballPath, tsVersion: TS6_VERSION, tempDirs },
+        {
+          fixtureName: "ts6-esm-modern",
+          packageTemplateFile: "package.module.json",
+          tsconfigTemplateFile: "tsconfig.nodenext.json",
+          withRuntime: true,
+        },
+      );
+    },
+    TS_TIMEOUT_MS,
+  );
+
+  it(
+    `runs TS CJS modern lane (${TS6_VERSION})`,
+    async () => {
+      await runTsLane(
+        { repoRoot, tarballPath, tsVersion: TS6_VERSION, tempDirs },
+        {
+          fixtureName: "ts6-cjs-modern",
+          packageTemplateFile: "package.commonjs.json",
+          tsconfigTemplateFile: "tsconfig.nodenext.json",
+          withRuntime: true,
+        },
+      );
+    },
+    TS_TIMEOUT_MS,
+  );
+
+  it(
+    `runs TS bundler compile-only lane (${TS6_VERSION})`,
+    async () => {
+      await runTsLane(
+        { repoRoot, tarballPath, tsVersion: TS6_VERSION, tempDirs },
+        {
+          fixtureName: "ts6-bundler",
+          packageTemplateFile: "package.module.json",
+          tsconfigTemplateFile: "tsconfig.bundler.json",
+          withRuntime: false,
+        },
+      );
+    },
+    TS_TIMEOUT_MS,
+  );
+
+  it(
+    `runs TS CJS node16 lane (${TS6_VERSION})`,
+    async () => {
+      await runTsLane(
+        { repoRoot, tarballPath, tsVersion: TS6_VERSION, tempDirs },
+        {
+          fixtureName: "ts6-cjs-node16",
+          packageTemplateFile: "package.commonjs.json",
+          tsconfigTemplateFile: "tsconfig.node16.json",
+          withRuntime: true,
+        },
+      );
+    },
+    TS_TIMEOUT_MS,
+  );
+});
diff --git a/test/consumer/fixtures/js-cjs/outbound-http-contract.cjs b/test/consumer/fixtures/js-cjs/outbound-http-contract.cjs
new file mode 100644
index 000000000..972d195d7
--- /dev/null
+++ b/test/consumer/fixtures/js-cjs/outbound-http-contract.cjs
@@ -0,0 +1,113 @@
+const assert = require("node:assert/strict");
+const { createServer } = require("node:http");
+const { once } = require("node:events");
+const { LineBotClient } = require("@line/bot-sdk");
+
+const requests = [];
+const server = createServer(async (req, res) => {
+  const chunks = [];
+  for await (const chunk of req) {
+    chunks.push(chunk);
+  }
+  const body = Buffer.concat(chunks).toString("utf8");
+  requests.push({
+    method: req.method,
+    url: req.url,
+    auth: req.headers.authorization,
+    body,
+  });
+
+  if (req.method === "GET" && req.url === "/v2/bot/info") {
+    res.writeHead(200, { "content-type": "application/json" });
+    res.end(
+      JSON.stringify({
+        userId: "U1234567890",
+        basicId: "@testbot",
+        displayName: "Test Bot",
+      }),
+    );
+    return;
+  }
+
+  if (
+    req.method === "GET" &&
+    req.url === "/v2/bot/message/message-1/content/transcoding"
+  ) {
+    res.writeHead(200, { "content-type": "application/json" });
+    res.end(JSON.stringify({ status: "succeeded" }));
+    return;
+  }
+
+  if (req.method === "POST" && req.url === "/module/auth/v1/token") {
+    res.writeHead(200, { "content-type": "application/json" });
+    res.end(JSON.stringify({ access_token: "module-token" }));
+    return;
+  }
+
+  res.writeHead(404, { "content-type": "application/json" });
+  res.end(JSON.stringify({ message: "Not Found" }));
+});
+
+async function main() {
+  server.listen(0, "127.0.0.1");
+  await once(server, "listening");
+
+  const address = server.address();
+  if (!address || typeof address === "string") {
+    throw new Error("failed to determine server address");
+  }
+
+  const baseUrl = `http://127.0.0.1:${address.port}`;
+
+  try {
+    const client = LineBotClient.fromChannelAccessToken({
+      channelAccessToken: "DUMMY_TOKEN",
+      apiBaseURL: baseUrl,
+      dataApiBaseURL: baseUrl,
+      managerBaseURL: baseUrl,
+    });
+
+    const botInfo = await client.getBotInfo();
+    assert.equal(botInfo.displayName, "Test Bot");
+
+    const transcoding =
+      await client.getMessageContentTranscodingByMessageId("message-1");
+    assert.equal(transcoding.status, "succeeded");
+
+    await client.attachModule(
+      "authorization_code",
+      "code-1",
+      "https://example.com/callback",
+    );
+
+    assert.equal(requests.length, 3);
+
+    assert.deepEqual(
+      requests.map(request => ({ method: request.method, url: request.url })),
+      [
+        { method: "GET", url: "/v2/bot/info" },
+        {
+          method: "GET",
+          url: "/v2/bot/message/message-1/content/transcoding",
+        },
+        { method: "POST", url: "/module/auth/v1/token" },
+      ],
+    );
+
+    for (const request of requests) {
+      assert.equal(request.auth, "Bearer DUMMY_TOKEN");
+    }
+
+    const formBody = requests[2]?.body ?? "";
+    assert.match(formBody, /grant_type=authorization_code/);
+    assert.match(formBody, /code=code-1/);
+    assert.match(formBody, /redirect_uri=https%3A%2F%2Fexample.com%2Fcallback/);
+  } finally {
+    server.close();
+  }
+}
+
+main().catch(error => {
+  console.error(error);
+  process.exitCode = 1;
+});
diff --git a/test/consumer/fixtures/js-cjs/package.json b/test/consumer/fixtures/js-cjs/package.json
new file mode 100644
index 000000000..7dbeb4f06
--- /dev/null
+++ b/test/consumer/fixtures/js-cjs/package.json
@@ -0,0 +1,5 @@
+{
+  "name": "consumer-js-cjs",
+  "private": true,
+  "type": "commonjs"
+}
diff --git a/test/consumer/fixtures/js-cjs/resolution-load-check.cjs b/test/consumer/fixtures/js-cjs/resolution-load-check.cjs
new file mode 100644
index 000000000..9fae3c8a8
--- /dev/null
+++ b/test/consumer/fixtures/js-cjs/resolution-load-check.cjs
@@ -0,0 +1,10 @@
+const assert = require("node:assert/strict");
+const sdk = require("@line/bot-sdk");
+
+assert.equal(typeof sdk.middleware, "function");
+assert.equal(typeof sdk.LineBotClient.fromChannelAccessToken, "function");
+
+const client = sdk.LineBotClient.fromChannelAccessToken({
+  channelAccessToken: "DUMMY_TOKEN",
+});
+assert.equal(typeof client.getBotInfo, "function");
diff --git a/test/consumer/fixtures/js-cjs/webhook-signature-contract.cjs b/test/consumer/fixtures/js-cjs/webhook-signature-contract.cjs
new file mode 100644
index 000000000..d83031374
--- /dev/null
+++ b/test/consumer/fixtures/js-cjs/webhook-signature-contract.cjs
@@ -0,0 +1,73 @@
+const assert = require("node:assert/strict");
+const { createHmac } = require("node:crypto");
+const { createServer } = require("node:http");
+const { once } = require("node:events");
+const { middleware } = require("@line/bot-sdk");
+
+const channelSecret = "channel-secret";
+
+const makeSignature = body => {
+  return createHmac("sha256", channelSecret).update(body).digest("base64");
+};
+
+const mw = middleware({ channelSecret });
+
+const server = createServer((req, res) => {
+  mw(req, res, err => {
+    if (err) {
+      res.statusCode = 401;
+      res.end("invalid");
+      return;
+    }
+
+    assert.equal(Array.isArray(req.body.events), true);
+    res.statusCode = 200;
+    res.end("ok");
+  });
+});
+
+async function main() {
+  server.listen(0, "127.0.0.1");
+  await once(server, "listening");
+
+  const address = server.address();
+  if (!address || typeof address === "string") {
+    throw new Error("failed to determine server address");
+  }
+
+  const url = `http://127.0.0.1:${address.port}/webhook`;
+
+  const payload = JSON.stringify({
+    destination: "UDEST",
+    events: [{ type: "message", message: { type: "text", text: "hi" } }],
+  });
+
+  try {
+    const okRes = await fetch(url, {
+      method: "POST",
+      headers: {
+        "content-type": "application/json",
+        "x-line-signature": makeSignature(payload),
+      },
+      body: payload,
+    });
+    assert.equal(okRes.status, 200);
+
+    const ngRes = await fetch(url, {
+      method: "POST",
+      headers: {
+        "content-type": "application/json",
+        "x-line-signature": "invalid-signature",
+      },
+      body: payload,
+    });
+    assert.equal(ngRes.status, 401);
+  } finally {
+    server.close();
+  }
+}
+
+main().catch(error => {
+  console.error(error);
+  process.exitCode = 1;
+});
diff --git a/test/consumer/fixtures/js-esm/outbound-http-contract.mjs b/test/consumer/fixtures/js-esm/outbound-http-contract.mjs
new file mode 100644
index 000000000..462aeaca9
--- /dev/null
+++ b/test/consumer/fixtures/js-esm/outbound-http-contract.mjs
@@ -0,0 +1,103 @@
+import assert from "node:assert/strict";
+import { createServer } from "node:http";
+import { once } from "node:events";
+import { LineBotClient } from "@line/bot-sdk";
+
+const requests = [];
+const server = createServer(async (req, res) => {
+  const chunks = [];
+  for await (const chunk of req) {
+    chunks.push(chunk);
+  }
+  const body = Buffer.concat(chunks).toString("utf8");
+  requests.push({
+    method: req.method,
+    url: req.url,
+    auth: req.headers.authorization,
+    body,
+  });
+
+  if (req.method === "GET" && req.url === "/v2/bot/info") {
+    res.writeHead(200, { "content-type": "application/json" });
+    res.end(
+      JSON.stringify({
+        userId: "U1234567890",
+        basicId: "@testbot",
+        displayName: "Test Bot",
+      }),
+    );
+    return;
+  }
+
+  if (
+    req.method === "GET" &&
+    req.url === "/v2/bot/message/message-1/content/transcoding"
+  ) {
+    res.writeHead(200, { "content-type": "application/json" });
+    res.end(JSON.stringify({ status: "succeeded" }));
+    return;
+  }
+
+  if (req.method === "POST" && req.url === "/module/auth/v1/token") {
+    res.writeHead(200, { "content-type": "application/json" });
+    res.end(JSON.stringify({ access_token: "module-token" }));
+    return;
+  }
+
+  res.writeHead(404, { "content-type": "application/json" });
+  res.end(JSON.stringify({ message: "Not Found" }));
+});
+
+server.listen(0, "127.0.0.1");
+await once(server, "listening");
+
+const address = server.address();
+if (!address || typeof address === "string") {
+  throw new Error("failed to determine server address");
+}
+
+const baseUrl = `http://127.0.0.1:${address.port}`;
+
+try {
+  const client = LineBotClient.fromChannelAccessToken({
+    channelAccessToken: "DUMMY_TOKEN",
+    apiBaseURL: baseUrl,
+    dataApiBaseURL: baseUrl,
+    managerBaseURL: baseUrl,
+  });
+
+  const botInfo = await client.getBotInfo();
+  assert.equal(botInfo.displayName, "Test Bot");
+
+  const transcoding =
+    await client.getMessageContentTranscodingByMessageId("message-1");
+  assert.equal(transcoding.status, "succeeded");
+
+  await client.attachModule(
+    "authorization_code",
+    "code-1",
+    "https://example.com/callback",
+  );
+
+  assert.equal(requests.length, 3);
+
+  assert.deepEqual(
+    requests.map(request => ({ method: request.method, url: request.url })),
+    [
+      { method: "GET", url: "/v2/bot/info" },
+      { method: "GET", url: "/v2/bot/message/message-1/content/transcoding" },
+      { method: "POST", url: "/module/auth/v1/token" },
+    ],
+  );
+
+  for (const request of requests) {
+    assert.equal(request.auth, "Bearer DUMMY_TOKEN");
+  }
+
+  const formBody = requests[2]?.body ?? "";
+  assert.match(formBody, /grant_type=authorization_code/);
+  assert.match(formBody, /code=code-1/);
+  assert.match(formBody, /redirect_uri=https%3A%2F%2Fexample.com%2Fcallback/);
+} finally {
+  server.close();
+}
diff --git a/test/consumer/fixtures/js-esm/package.json b/test/consumer/fixtures/js-esm/package.json
new file mode 100644
index 000000000..d3042e00f
--- /dev/null
+++ b/test/consumer/fixtures/js-esm/package.json
@@ -0,0 +1,5 @@
+{
+  "name": "consumer-js-esm",
+  "private": true,
+  "type": "module"
+}
diff --git a/test/consumer/fixtures/js-esm/resolution-load-check.mjs b/test/consumer/fixtures/js-esm/resolution-load-check.mjs
new file mode 100644
index 000000000..b6a865c2f
--- /dev/null
+++ b/test/consumer/fixtures/js-esm/resolution-load-check.mjs
@@ -0,0 +1,10 @@
+import assert from "node:assert/strict";
+import { LineBotClient, middleware } from "@line/bot-sdk";
+
+assert.equal(typeof middleware, "function");
+assert.equal(typeof LineBotClient.fromChannelAccessToken, "function");
+
+const client = LineBotClient.fromChannelAccessToken({
+  channelAccessToken: "DUMMY_TOKEN",
+});
+assert.equal(typeof client.getBotInfo, "function");
diff --git a/test/consumer/fixtures/js-esm/webhook-signature-contract.mjs b/test/consumer/fixtures/js-esm/webhook-signature-contract.mjs
new file mode 100644
index 000000000..14c54689a
--- /dev/null
+++ b/test/consumer/fixtures/js-esm/webhook-signature-contract.mjs
@@ -0,0 +1,66 @@
+import assert from "node:assert/strict";
+import { createHmac } from "node:crypto";
+import { createServer } from "node:http";
+import { once } from "node:events";
+import { middleware } from "@line/bot-sdk";
+
+const channelSecret = "channel-secret";
+
+const makeSignature = body => {
+  return createHmac("sha256", channelSecret).update(body).digest("base64");
+};
+
+const mw = middleware({ channelSecret });
+
+const server = createServer((req, res) => {
+  mw(req, res, err => {
+    if (err) {
+      res.statusCode = 401;
+      res.end("invalid");
+      return;
+    }
+
+    assert.equal(Array.isArray(req.body.events), true);
+    res.statusCode = 200;
+    res.end("ok");
+  });
+});
+
+server.listen(0, "127.0.0.1");
+await once(server, "listening");
+
+const address = server.address();
+if (!address || typeof address === "string") {
+  throw new Error("failed to determine server address");
+}
+
+const url = `http://127.0.0.1:${address.port}/webhook`;
+
+const payload = JSON.stringify({
+  destination: "UDEST",
+  events: [{ type: "message", message: { type: "text", text: "hi" } }],
+});
+
+try {
+  const okRes = await fetch(url, {
+    method: "POST",
+    headers: {
+      "content-type": "application/json",
+      "x-line-signature": makeSignature(payload),
+    },
+    body: payload,
+  });
+  assert.equal(okRes.status, 200);
+
+  const ngRes = await fetch(url, {
+    method: "POST",
+    headers: {
+      "content-type": "application/json",
+      "x-line-signature": "invalid-signature",
+    },
+    body: payload,
+  });
+  assert.equal(ngRes.status, 401);
+} finally {
+  server.close();
+}
diff --git a/test/consumer/runner/index.ts b/test/consumer/runner/index.ts
new file mode 100644
index 000000000..8a8b8a94a
--- /dev/null
+++ b/test/consumer/runner/index.ts
@@ -0,0 +1,206 @@
+import assert from "node:assert/strict";
+import { spawnSync } from "node:child_process";
+import { cp, mkdtemp, readFile, rm, writeFile } from "node:fs/promises";
+import os from "node:os";
+import path from "node:path";
+
+export interface CmdResult {
+  readonly stdout: string;
+  readonly stderr: string;
+}
+
+export interface PackagedPackageJson {
+  readonly main: string;
+  readonly types: string;
+  readonly exports: {
+    readonly ".": {
+      readonly import: {
+        readonly types: string;
+        readonly default: string;
+      };
+      readonly require: {
+        readonly types: string;
+        readonly default: string;
+      };
+    };
+  };
+}
+
+const COMMAND_TIMEOUT_MS = 45_000;
+const NPM_TIMEOUT_MS = 60_000;
+
+export function runCommand(
+  cwd: string,
+  command: string,
+  args: string[],
+  env: Record<string, string> = {},
+  timeoutMs: number = COMMAND_TIMEOUT_MS,
+): CmdResult {
+  const defaultEnv: Record<string, string> = {};
+  if (command === "npm") {
+    if (env.NPM_CONFIG_CACHE == null) {
+      defaultEnv.NPM_CONFIG_CACHE = path.join(os.tmpdir(), "bot-sdk-npm-cache");
+    }
+    if (env.NPM_CONFIG_REGISTRY == null) {
+      defaultEnv.NPM_CONFIG_REGISTRY = "https://registry.npmjs.org";
+    }
+  }
+
+  const result = spawnSync(command, args, {
+    cwd,
+    env: { ...process.env, ...defaultEnv, ...env },
+    encoding: "utf8",
+    timeout: timeoutMs,
+  });
+
+  if (result.error) {
+    const joined = [
+      `$ ${command} ${args.join(" ")}`,
+      `cwd: ${cwd}`,
+      `timeoutMs: ${timeoutMs}`,
+      result.stdout,
+      result.stderr,
+      result.error.message,
+    ]
+      .filter(Boolean)
+      .join("\n");
+    throw new Error(joined);
+  }
+
+  if (result.status !== 0) {
+    const joined = [
+      `$ ${command} ${args.join(" ")}`,
+      `cwd: ${cwd}`,
+      `timeoutMs: ${timeoutMs}`,
+      result.stdout,
+      result.stderr,
+    ]
+      .filter(Boolean)
+      .join("\n");
+    throw new Error(joined);
+  }
+
+  return {
+    stdout: result.stdout,
+    stderr: result.stderr,
+  };
+}
+
+export async function createTempDir(prefix: string): Promise<string> {
+  return mkdtemp(path.join(os.tmpdir(), prefix));
+}
+
+export async function removeDir(dirPath: string): Promise<void> {
+  await rm(dirPath, { recursive: true, force: true });
+}
+
+export async function prepareFixtureDir(
+  tempDirs: string[],
+  name: string,
+): Promise<string> {
+  const dir = await createTempDir(`bot-sdk-consumer-${name}-`);
+  tempDirs.push(dir);
+  return dir;
+}
+
+export async function copyDir(src: string, dst: string): Promise<void> {
+  await cp(src, dst, { recursive: true });
+}
+
+export async function buildPackedTarball(
+  repoRoot: string,
+  outDir: string,
+): Promise<string> {
+  const { stdout } = runCommand(
+    repoRoot,
+    "npm",
+    ["pack", "--json", "--pack-destination", outDir],
+    {},
+    NPM_TIMEOUT_MS,
+  );
+  const parsed = JSON.parse(stdout) as Array<{ filename: string }>;
+  const filename = parsed[0]?.filename;
+  assert.ok(filename, "npm pack --json did not return filename");
+  return path.join(outDir, filename);
+}
+
+export async function readTarPackageJson(
+  repoRoot: string,
+  tarballPath: string,
+): Promise<PackagedPackageJson> {
+  const { stdout } = runCommand(repoRoot, "tar", [
+    "-xOf",
+    tarballPath,
+    "package/package.json",
+  ]);
+  return JSON.parse(stdout) as PackagedPackageJson;
+}
+
+export function listTarEntries(
+  repoRoot: string,
+  tarballPath: string,
+): string[] {
+  const { stdout } = runCommand(repoRoot, "tar", ["-tf", tarballPath]);
+  return stdout
+    .split("\n")
+    .map(line => line.trim())
+    .filter(line => line.length > 0);
+}
+
+export async function materializeTsFixture(params: {
+  readonly repoRoot: string;
+  readonly outDir: string;
+  readonly packageTemplateFile: string;
+  readonly tsconfigTemplateFile?: string;
+  readonly tsVersion: string;
+}): Promise<void> {
+  const templateRoot = path.join(
+    params.repoRoot,
+    "test/consumer/templates/ts-modern",
+  );
+  await copyDir(path.join(templateRoot, "files"), params.outDir);
+
+  const packageTemplate = await readFile(
+    path.join(templateRoot, params.packageTemplateFile),
+    "utf8",
+  );
+  const packageJson = packageTemplate.replace(
+    "__TS_VERSION__",
+    params.tsVersion,
+  );
+  await writeFile(
+    path.join(params.outDir, "package.json"),
+    packageJson,
+    "utf8",
+  );
+
+  const tsconfig = await readFile(
+    path.join(
+      templateRoot,
+      params.tsconfigTemplateFile ?? "tsconfig.nodenext.json",
+    ),
+    "utf8",
+  );
+  await writeFile(path.join(params.outDir, "tsconfig.json"), tsconfig, "utf8");
+}
+
+export function installSdkTarball(
+  projectDir: string,
+  tarballPath: string,
+): void {
+  runCommand(
+    projectDir,
+    "npm",
+    [
+      "install",
+      "--no-audit",
+      "--no-fund",
+      "--ignore-scripts",
+      "--prefer-offline",
+      "--no-save",
+      `file:${tarballPath}`,
+    ],
+    {},
+    NPM_TIMEOUT_MS,
+  );
+}
diff --git a/test/consumer/runner/ts-lane.ts b/test/consumer/runner/ts-lane.ts
new file mode 100644
index 000000000..e8e35d0eb
--- /dev/null
+++ b/test/consumer/runner/ts-lane.ts
@@ -0,0 +1,43 @@
+import {
+  installSdkTarball,
+  materializeTsFixture,
+  prepareFixtureDir,
+  runCommand,
+} from "./index";
+
+export interface TsLaneConfig {
+  readonly fixtureName: string;
+  readonly packageTemplateFile: "package.module.json" | "package.commonjs.json";
+  readonly tsconfigTemplateFile: string;
+  readonly withRuntime: boolean;
+}
+
+export interface TsLaneRunContext {
+  readonly repoRoot: string;
+  readonly tarballPath: string;
+  readonly tsVersion: string;
+  readonly tempDirs: string[];
+}
+
+export async function runTsLane(
+  context: TsLaneRunContext,
+  config: TsLaneConfig,
+): Promise<void> {
+  const fixtureDir = await prepareFixtureDir(
+    context.tempDirs,
+    config.fixtureName,
+  );
+  await materializeTsFixture({
+    repoRoot: context.repoRoot,
+    outDir: fixtureDir,
+    packageTemplateFile: config.packageTemplateFile,
+    tsconfigTemplateFile: config.tsconfigTemplateFile,
+    tsVersion: context.tsVersion,
+  });
+
+  installSdkTarball(fixtureDir, context.tarballPath);
+  runCommand(fixtureDir, "npm", ["run", "build"]);
+  if (config.withRuntime) {
+    runCommand(fixtureDir, "npm", ["run", "run:resolution"]);
+  }
+}
diff --git a/test/consumer/templates/ts-modern/files/src/resolution-load-check.ts b/test/consumer/templates/ts-modern/files/src/resolution-load-check.ts
new file mode 100644
index 000000000..074ad257e
--- /dev/null
+++ b/test/consumer/templates/ts-modern/files/src/resolution-load-check.ts
@@ -0,0 +1,10 @@
+import * as assert from "node:assert/strict";
+import { LineBotClient, middleware } from "@line/bot-sdk";
+
+assert.equal(typeof middleware, "function");
+assert.equal(typeof LineBotClient.fromChannelAccessToken, "function");
+
+const client = LineBotClient.fromChannelAccessToken({
+  channelAccessToken: "DUMMY_TOKEN",
+});
+assert.equal(typeof client.getBotInfo, "function");
diff --git a/test/consumer/templates/ts-modern/package.commonjs.json b/test/consumer/templates/ts-modern/package.commonjs.json
new file mode 100644
index 000000000..d75ac6294
--- /dev/null
+++ b/test/consumer/templates/ts-modern/package.commonjs.json
@@ -0,0 +1,12 @@
+{
+  "name": "consumer-ts-modern-cjs",
+  "private": true,
+  "type": "commonjs",
+  "devDependencies": {
+    "typescript": "__TS_VERSION__"
+  },
+  "scripts": {
+    "build": "tsc -p ./tsconfig.json",
+    "run:resolution": "node ./dist/resolution-load-check.js"
+  }
+}
diff --git a/test/consumer/templates/ts-modern/package.module.json b/test/consumer/templates/ts-modern/package.module.json
new file mode 100644
index 000000000..b934ce939
--- /dev/null
+++ b/test/consumer/templates/ts-modern/package.module.json
@@ -0,0 +1,12 @@
+{
+  "name": "consumer-ts-modern-esm",
+  "private": true,
+  "type": "module",
+  "devDependencies": {
+    "typescript": "__TS_VERSION__"
+  },
+  "scripts": {
+    "build": "tsc -p ./tsconfig.json",
+    "run:resolution": "node ./dist/resolution-load-check.js"
+  }
+}
diff --git a/test/consumer/templates/ts-modern/tsconfig.bundler.json b/test/consumer/templates/ts-modern/tsconfig.bundler.json
new file mode 100644
index 000000000..f07f73f54
--- /dev/null
+++ b/test/consumer/templates/ts-modern/tsconfig.bundler.json
@@ -0,0 +1,17 @@
+{
+  "compilerOptions": {
+    "target": "ES2022",
+    "module": "ESNext",
+    "moduleResolution": "Bundler",
+    "strict": true,
+    "skipLibCheck": false,
+    "types": [
+      "node"
+    ],
+    "rootDir": "src",
+    "outDir": "dist"
+  },
+  "include": [
+    "src/**/*.ts"
+  ]
+}
diff --git a/test/consumer/templates/ts-modern/tsconfig.legacy-commonjs.json b/test/consumer/templates/ts-modern/tsconfig.legacy-commonjs.json
new file mode 100644
index 000000000..0e77706d8
--- /dev/null
+++ b/test/consumer/templates/ts-modern/tsconfig.legacy-commonjs.json
@@ -0,0 +1,17 @@
+{
+  "compilerOptions": {
+    "target": "ES2022",
+    "module": "CommonJS",
+    "moduleResolution": "Node",
+    "strict": true,
+    "skipLibCheck": false,
+    "types": [
+      "node"
+    ],
+    "rootDir": "src",
+    "outDir": "dist"
+  },
+  "include": [
+    "src/**/*.ts"
+  ]
+}
diff --git a/test/consumer/templates/ts-modern/tsconfig.node16.json b/test/consumer/templates/ts-modern/tsconfig.node16.json
new file mode 100644
index 000000000..8e4d2825a
--- /dev/null
+++ b/test/consumer/templates/ts-modern/tsconfig.node16.json
@@ -0,0 +1,17 @@
+{
+  "compilerOptions": {
+    "target": "ES2022",
+    "module": "Node16",
+    "moduleResolution": "Node16",
+    "strict": true,
+    "skipLibCheck": false,
+    "types": [
+      "node"
+    ],
+    "rootDir": "src",
+    "outDir": "dist"
+  },
+  "include": [
+    "src/**/*.ts"
+  ]
+}
diff --git a/test/consumer/templates/ts-modern/tsconfig.nodenext.json b/test/consumer/templates/ts-modern/tsconfig.nodenext.json
new file mode 100644
index 000000000..075995082
--- /dev/null
+++ b/test/consumer/templates/ts-modern/tsconfig.nodenext.json
@@ -0,0 +1,17 @@
+{
+  "compilerOptions": {
+    "target": "ES2022",
+    "module": "NodeNext",
+    "moduleResolution": "NodeNext",
+    "strict": true,
+    "skipLibCheck": false,
+    "types": [
+      "node"
+    ],
+    "rootDir": "src",
+    "outDir": "dist"
+  },
+  "include": [
+    "src/**/*.ts"
+  ]
+}