diff --git a/__tests__/axios.spec.ts b/__tests__/axios.spec.ts
new file mode 100644
index 0000000..b12285c
--- /dev/null
+++ b/__tests__/axios.spec.ts
@@ -0,0 +1,25 @@
+import { createAxios } from '../src/axios';
+
+describe('请求非 JSON 数据', () => {
+  it('XML 数据', async () => {
+    const axios = createAxios();
+    const res = await axios.get('https://httpbin.org/robots.txt');
+    expect(res.data).toBe('User-agent: *\nDisallow: /deny\n');
+  });
+});
+
+describe('请求 JSON 数据', () => {
+  it('普通数据', async () => {
+    const axios = createAxios();
+    const res = await axios.get('https://httpbin.org/json');
+    const expected = JSON.parse('{"slideshow":{"author":"Yours Truly","date":"date of publication","slides":[{"title":"Wake up to WonderWidgets!","type":"all"},{"items":["Why <em>WonderWidgets</em> are great","Who <em>buys</em> WonderWidgets"],"title":"Overview","type":"all"}],"title":"Sample Slide Show"}}');
+    expect(res.data).toMatchObject(expected);
+  });
+
+  it('带 bigint', async () => {
+    const axios = createAxios();
+    const obj = { id: 9223372036854775808n };
+    const res = await axios.post('https://httpbin.org/anything', obj);
+    expect(res.data.json).toMatchObject(obj);
+  });
+});
diff --git a/package.json b/package.json
index 5e92e30..6695856 100644
--- a/package.json
+++ b/package.json
@@ -59,6 +59,7 @@
   },
   "dependencies": {
     "axios": "^1.6.2",
+    "is-plain-object": "^5.0.0",
     "js-base64": "^3.7.5",
     "json-bigint": "^1.0.0",
     "mitt": "^3.0.1",
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index f7951dc..aabc4a7 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -4,6 +4,9 @@ dependencies:
   axios:
     specifier: ^1.6.2
     version: 1.6.2
+  is-plain-object:
+    specifier: ^5.0.0
+    version: 5.0.0
   js-base64:
     specifier: ^3.7.5
     version: 3.7.5
@@ -3239,6 +3242,11 @@ packages:
     engines: {node: '>=8'}
     dev: true
 
+  /is-plain-object@5.0.0:
+    resolution: {integrity: sha512-VRSzKkbMm5jMDoKLbltAkFQ5Qr7VDiTFGXxYFXXowVj387GeGNOCsOH6Msy00SGZ3Fp84b1Naa1psqgcCIEP5Q==}
+    engines: {node: '>=0.10.0'}
+    dev: false
+
   /is-stream@2.0.1:
     resolution: {integrity: sha512-hFoiJiTl63nn+kstHGBtewWSKnQLpyb155KHheA1l39uvtO9nWIop1p3udqPcUd/xbF1VLMO4n7OI6p7RbngDg==}
     engines: {node: '>=8'}
diff --git a/src/axios.ts b/src/axios.ts
index 2b8c0c1..27d7014 100644
--- a/src/axios.ts
+++ b/src/axios.ts
@@ -1,4 +1,5 @@
-import axios, { AxiosResponse, CreateAxiosDefaults } from 'axios';
+import axios, { AxiosResponse, CreateAxiosDefaults, InternalAxiosRequestConfig } from 'axios';
+import { isPlainObject } from 'is-plain-object';
 import jsonBigint from 'json-bigint';
 import { FanbookApiError } from './error';
 
@@ -7,21 +8,40 @@ export const bigintJsonParser = jsonBigint({
   useNativeBigInt: true,
 });
 
+/** 测试 Content-Type 是否为 json 的正则表达式。 */
+const isJsonContentType = /^application\/(.*\+)?json$/;
 /**
- * 转换请求响应。
- * @param data 响应体
- * @returns 转换后的响应体
+ * 解析请求 bigint。
+ * @param req 请求数据
+ * @returns 转换后的请求数据
  */
-function parseResponseBigint(data: unknown) {
-  console.log(data);
-  if (typeof data === 'string') {
-    try { // 能转 JSON 就转
-      return bigintJsonParser.parse(data);
-    } catch { // 不能转原样返回
-      return data;
-    }
+function requestBigintInterceptor(req: InternalAxiosRequestConfig) {
+  const type = req.headers['content-type'];
+  if (
+    (typeof type === 'string' && isJsonContentType.test(type))
+    || isPlainObject(req.data)
+  ) { // 是 JSON
+    req.data = bigintJsonParser.stringify(req.data);
+    req.headers['content-type'] ??= 'application/json';
   }
-  return data;
+  return req;
+}
+/**
+ * 解析响应 bigint。
+ * @param res 响应数据
+ * @returns 转换后的响应数据
+ */
+function responseBigintInterceptor(res: AxiosResponse) {
+  // 非 json 不处理
+  const type = res.headers['content-type'];
+  if (typeof type !== 'string') return res;
+  if (!isJsonContentType.test(type)) return res;
+
+  // 带 bigint 解析 json，不行就算了
+  try {
+    res.data = bigintJsonParser.parse(res.data);
+  } catch {}
+  return res;
 }
 
 /**
@@ -30,13 +50,17 @@ function parseResponseBigint(data: unknown) {
  * @returns Axios 实例
  */
 export function createAxios(options?: CreateAxiosDefaults) {
-  let pipes = options?.transformResponse;
-  // 将 pipes 转数组，然后浅拷贝，保证后续修改 options 不会影响到 pipes
-  if (Array.isArray(pipes)) pipes = [...pipes];
-  else pipes = pipes ? [pipes] : []; // pipes 可能为 undefined
-
-  pipes.unshift(parseResponseBigint);
-  return axios.create(options);
+  const inst = axios.create({
+    ...options,
+    // 由于 axios 自动解析 json 导致 bigint 精度丢失，要阻止它的 json 解析
+    // 如果用户已经给定 pipes，它会阻止 json 解析
+    // 如果用户没有给定 pipes，要用 `(x) => x` 阻止 json 解析
+    transformRequest: options?.transformRequest ?? ((x) => x),
+    transformResponse: options?.transformResponse ?? ((x) => x),
+  });
+  inst.interceptors.request.use(requestBigintInterceptor);
+  inst.interceptors.response.use(responseBigintInterceptor);
+  return inst;
 }
 
 /**