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

> callsites@4.2.0 is ESM-only. ESM-only since 4.0.0 — last CommonJS version is 3.1.0.

Get callsites from the V8 stack trace API

Last verified Sep 9, 2026 against callsites@4.2.0.

callsites 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 Apr 6, 2019; it declares support for Node.js >=6.

On Node.js 20.19+, 22.12+ and newer, require("callsites") 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("callsites") fails with ERR_REQUIRE_ESM.

## What to do

1. On Node.js 20.19+, 22.12+ and newer, require("callsites") 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 callsites = await import("callsites"). That works on every Node.js version the package supports (>=12.20).
3. If you need a synchronous require() or run Node.js 18: npm install callsites@3.1.0, the last CommonJS release (published Apr 6, 2019); it declares Node.js >=6.
4. TypeScript: types are bundled; install nothing extra.

## Facts

- Latest: 4.2.0 (Jun 29, 2024)
- Module format: ESM-only
- Last CommonJS version: 3.1.0
- ESM-only since: 4.0.0 (Aug 8, 2021)
- TypeScript types: bundled
- Node engines: >=12.20
- Weekly downloads: 136.7M
- License: MIT

## Runtime test results for callsites@4.2.0

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

| Runtime | require("callsites") | import "callsites" |
|---|---|---|
| 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 callsites

ES modules:

```js
import * as callsites from "callsites";
```

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 callsites = require("callsites");

// Any Node.js version the package supports (>=12.20), from an async function:
async function main() {
  const callsites = await import("callsites");
}

// Or pin the last CommonJS release (declares Node.js >=6):
// npm install callsites@3.1.0
```

## Module format by version

Derived from the type, main and exports fields of every stable release on npm (10 versions; the newest 10 shown).

| Versions | Format | First published |
|---|---|---|
| 4.0.0 – 4.2.0 | ESM-only | Aug 8, 2021 |
| 0.1.0 – 3.1.0 | CommonJS | Apr 19, 2014 |

## Frequently asked

**Is callsites ESM-only?**

callsites@4.2.0 is ESM-only. callsites 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 Apr 6, 2019; it declares support for Node.js >=6.

**Which version of callsites still supports CommonJS / require()?**

3.1.0 is the last version of callsites with a CommonJS build; it declares Node.js >=6. Install it with "npm install callsites@3.1.0". Every version from 4.0.0 on is ESM-only.

**How do I use callsites from a CommonJS file?**

From a CommonJS file, use a dynamic import inside an async function: const callsites = await import("callsites"). That works on every Node.js version the package supports (>=12.20). On Node.js 20.19+, 22.12+ and newer, require("callsites") works with the latest version: Node.js loads synchronous ES modules through require(). Verified on Node.js 20, 22, 24 and 26. Alternatively pin callsites@3.1.0 (declares Node.js >=6).

**Does callsites work in Bun?**

Yes. import "callsites" loaded successfully in Bun 1.4.0 on Sep 9, 2026.

**Does callsites ship TypeScript types?**

Yes. callsites bundles its own type declarations; no @types package is needed.

## Links

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