# Is mimic-response ESM-only? Can you require() it?

> mimic-response@4.0.0 is ESM-only. ESM-only since 4.0.0 — last CommonJS version is 3.1.0.

Mimic a Node.js HTTP response stream

Last verified Sep 9, 2026 against mimic-response@4.0.0.

mimic-response dropped its CommonJS build in 4.0.0 (August 2021). The last version with a plain require()-able CommonJS entry is 3.1.0, published May 14, 2020; it declares support for Node.js >=10.

On Node.js 20.19+, 22.12+ and newer, require("mimic-response") works with the latest version: Node.js loads synchronous ES modules through require(). Verified on Node.js 20, 22, 24 and 26. On Node.js 18, which has no require(esm), require("mimic-response") fails with ERR_REQUIRE_ESM.

## What to do

1. On Node.js 20.19+, 22.12+ and newer, require("mimic-response") works with the latest version: Node.js loads synchronous ES modules through require(). Verified on Node.js 20, 22, 24 and 26.
2. From a CommonJS file, use a dynamic import inside an async function: const mimicResponse = await import("mimic-response"). That works on every Node.js version the package supports (^12.20.0 || ^14.13.1 || >=16.0.0).
3. If you need a synchronous require() or run Node.js 18: npm install mimic-response@3.1.0, the last CommonJS release (published May 14, 2020); it declares Node.js >=10.
4. TypeScript: no types are available for mimic-response; declare the module yourself if you need them.

## Facts

- Latest: 4.0.0 (Aug 11, 2021)
- Module format: ESM-only
- Last CommonJS version: 3.1.0
- ESM-only since: 4.0.0 (Aug 11, 2021)
- TypeScript types: none
- Node engines: ^12.20.0 || ^14.13.1 || >=16.0.0
- Weekly downloads: 37.6M
- License: MIT

## Runtime test results for mimic-response@4.0.0

Installed and executed on Sep 9, 2026 with require("mimic-response") from a CommonJS file and import "mimic-response" from an ES module.

| Runtime | require("mimic-response") | import "mimic-response" |
|---|---|---|
| Node.js 18 | fails (ERR_REQUIRE_ESM) | works |
| Node.js 20 | works | works |
| Node.js 22 | works | works |
| Node.js 24 | works | works |
| Node.js 26 | works | works |
| Bun 1.4.0 | works | works |

## How to import mimic-response

ES modules:

```js
import * as mimicResponse from "mimic-response";
```

Namespace import shown because the ESM entry may have no default export; use named imports for what it exports.

CommonJS:

```js
// Node.js 20.19+, 22.12+ and newer (verified):
const mimicResponse = require("mimic-response");

// Any Node.js version the package supports (^12.20.0 || ^14.13.1 || >=16.0.0), from an async function:
async function main() {
  const mimicResponse = await import("mimic-response");
}

// Or pin the last CommonJS release (declares Node.js >=10):
// npm install mimic-response@3.1.0
```

## Module format by version

Derived from the type, main and exports fields of every stable release on npm (7 versions; the newest 7 shown).

| Versions | Format | First published |
|---|---|---|
| 4.0.0 | ESM-only | Aug 11, 2021 |
| 1.0.0 – 3.1.0 | CommonJS | Jun 2, 2017 |

## Frequently asked

**Is mimic-response ESM-only?**

mimic-response@4.0.0 is ESM-only. mimic-response dropped its CommonJS build in 4.0.0 (August 2021). The last version with a plain require()-able CommonJS entry is 3.1.0, published May 14, 2020; it declares support for Node.js >=10.

**Which version of mimic-response still supports CommonJS / require()?**

3.1.0 is the last version of mimic-response with a CommonJS build; it declares Node.js >=10. Install it with "npm install mimic-response@3.1.0". Every version from 4.0.0 on is ESM-only.

**How do I use mimic-response from a CommonJS file?**

From a CommonJS file, use a dynamic import inside an async function: const mimicResponse = await import("mimic-response"). That works on every Node.js version the package supports (^12.20.0 || ^14.13.1 || >=16.0.0). On Node.js 20.19+, 22.12+ and newer, require("mimic-response") works with the latest version: Node.js loads synchronous ES modules through require(). Verified on Node.js 20, 22, 24 and 26. Alternatively pin mimic-response@3.1.0 (declares Node.js >=10).

**Does mimic-response work in Bun?**

Yes. import "mimic-response" loaded successfully in Bun 1.4.0 on Sep 9, 2026.

**Does mimic-response ship TypeScript types?**

No. mimic-response ships no type declarations and there is no @types package for it.

## Links

- [mimic-response on npm](https://www.npmjs.com/package/mimic-response)
- [Source repository](https://github.com/sindresorhus/mimic-response)
- [HTML version](https://canirequire.com/package/mimic-response/)
- [JSON version](https://canirequire.com/package/mimic-response.json)

---

For scripts and AI agents: any package is at https://canirequire.com/package/<name>/index.md (Markdown) or https://canirequire.com/package/<name>.json (JSON); the site index is https://canirequire.com/llms.txt. Fetch the URL directly; no search needed.