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

> agent-base@9.0.0 is ESM-only. ESM-only since 8.0.0 — last CommonJS version is 7.1.4.

Turn a function into an `http.Agent` instance

Last verified Sep 9, 2026 against agent-base@9.0.0.

agent-base dropped its CommonJS build in 8.0.0 (March 2026). The last version with a plain require()-able CommonJS entry is 7.1.4, published Jul 7, 2025; it declares support for Node.js >= 14.

On Node.js 20.19+, 22.12+ and newer, require("agent-base") works with the latest version: Node.js loads synchronous ES modules through require(). Verified on Node.js 20, 22, 24 and 26. Node.js 18 has no require(esm), and agent-base@9.0.0 declares Node.js >= 20, so 18 is outside its supported range anyway.

agent-base@9.0.0 declares engines ">= 20", so Node.js 18 is outside its supported range regardless of module format.

## What to do

1. On Node.js 20.19+, 22.12+ and newer, require("agent-base") 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 agentBase = await import("agent-base"). That works on every Node.js version the package supports (>= 20).
3. If you need a synchronous require() or run Node.js 18: npm install agent-base@7.1.4, the last CommonJS release (published Jul 7, 2025); it declares Node.js >= 14.
4. agent-base@9.0.0 declares engines ">= 20", so Node.js 18 is unsupported regardless: upgrade Node.js or pin an older release.
5. TypeScript: types are bundled; install nothing extra.

## Facts

- Latest: 9.0.0 (Apr 1, 2026)
- Module format: ESM-only
- Last CommonJS version: 7.1.4
- ESM-only since: 8.0.0 (Mar 11, 2026)
- TypeScript types: bundled
- Node engines: >= 20
- Weekly downloads: 185.6M
- License: MIT

## Runtime test results for agent-base@9.0.0

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

| Runtime | require("agent-base") | import "agent-base" |
|---|---|---|
| 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 agent-base

ES modules:

```js
import * as agentBase from "agent-base";
```

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 agentBase = require("agent-base");

// Any Node.js version the package supports (>= 20), from an async function:
async function main() {
  const agentBase = await import("agent-base");
}

// Or pin the last CommonJS release (declares Node.js >= 14):
// npm install agent-base@7.1.4
```

## Module format by version

Derived from the type, main and exports fields of every stable release on npm (33 versions; the newest 33 shown).

| Versions | Format | First published |
|---|---|---|
| 8.0.0 – 9.0.0 | ESM-only | Mar 11, 2026 |
| 0.0.1 – 7.1.4 | CommonJS | Jul 9, 2013 |

## Frequently asked

**Is agent-base ESM-only?**

agent-base@9.0.0 is ESM-only. agent-base dropped its CommonJS build in 8.0.0 (March 2026). The last version with a plain require()-able CommonJS entry is 7.1.4, published Jul 7, 2025; it declares support for Node.js >= 14.

**Which version of agent-base still supports CommonJS / require()?**

7.1.4 is the last version of agent-base with a CommonJS build; it declares Node.js >= 14. Install it with "npm install agent-base@7.1.4". Every version from 8.0.0 on is ESM-only.

**How do I use agent-base from a CommonJS file?**

From a CommonJS file, use a dynamic import inside an async function: const agentBase = await import("agent-base"). That works on every Node.js version the package supports (>= 20). On Node.js 20.19+, 22.12+ and newer, require("agent-base") works with the latest version: Node.js loads synchronous ES modules through require(). Verified on Node.js 20, 22, 24 and 26. Alternatively pin agent-base@7.1.4 (declares Node.js >= 14).

**Does agent-base work in Bun?**

Yes. import "agent-base" loaded successfully in Bun 1.4.0 on Sep 9, 2026.

**Does agent-base ship TypeScript types?**

Yes. agent-base bundles its own type declarations; no @types package is needed.

## Links

- [agent-base on npm](https://www.npmjs.com/package/agent-base)
- [Source repository](https://github.com/TooTallNate/proxy-agents)
- [HTML version](https://canirequire.com/package/agent-base/)
- [JSON version](https://canirequire.com/package/agent-base.json)

---

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