Node.js 24 require(esm) Stabilization — Why NestJS 12's Shift to Pure ESM Was Possible

The ERR_REQUIRE_ESM error, a persistent headache in the JavaScript backend ecosystem, is finally fading into history. This is because Node.js 24 has stabilized the require(esm) feature, allowing CommonJS environments to load ESM packages directly and synchronously. This development paves the way for adopting the latest ESM packages naturally, without the need for complex bundler configurations or dual-build workarounds. Here, we break down the core of this change—which accelerates module integration across the backend—and its practical implications.

Node.js 24 require(esm): How It Works and Its Key Constraints

The ERR_REQUIRE_ESM error that has plagued JavaScript developers is finally resolved in Node.js 24. Led by core contributor Joyee Cheung, this mechanism enables CommonJS environments to load ESM packages directly and synchronously.

The underlying principle lies in the V8 engine synchronously parsing and analyzing the ESM module graph. Per the ECMAScript specification, ESM graphs without top-level await can be evaluated synchronously. The Node.js runtime leverages this to compile the module and return the result immediately.

As a result, existing CommonJS projects can invoke pure ESM libraries directly without complex modifications to their build toolchains.

// app.cjs (Node.js 24+ 환경)
const { someEsmFunction } = require('esm-only-package');

// 별도의 비동기 래핑 없이 즉시 동기 실행 가능
const result = someEsmFunction();
console.log(result);

However, this mechanism comes with a clear constraint: the ESM module graph being imported must not contain top-level await. If top-level await is present, the evaluation becomes asynchronous and returns a promise, leading to an ERR_REQUIRE_ASYNC_MODULE error when called via the synchronous require function.

Fortunately, most npm libraries avoid using top-level await for backward compatibility, meaning it can be used seamlessly in practical scenarios.

Why NestJS 12's ESM Transition Is Painless

The most significant change in the NestJS 12 roadmap is the conversion of all core packages to pure ESM. In the past, this decision would have caused critical disruptions to backward compatibility for existing CommonJS-based applications. However, thanks to the synchronous require(esm) provided by Node.js 24, developers can load and use the latest pure ESM packages without modifying a single line of their existing project code.

According to InfoQ's roadmap report and byteiota analysis, Kamil Myśliwiec, the creator of NestJS, emphasized that Node.js's support for require(esm) was 'the final piece of the puzzle that made the ESM transition truly viable.' Without this feature, the migration would have lacked significant practical utility. With compatibility barriers resolved at the runtime level, the framework's core team can confidently pursue a comprehensive overhaul.

Consequently, NestJS 12 sets a prime example by shedding long-standing compiler debt and complex module configurations without impacting existing business logic. Developers are finally liberated from the long-standing conflict between module systems, as they can now freely integrate ESM-only libraries without needing to restructure their projects immediately.

The End of Dual-Package Hurdles and Simplified Build Pipelines

Open-source library maintainers have long provided build artifacts for both CommonJS and ESM to support both environments. This often led to the 'Dual Package Hazard,' a persistent issue where an application inadvertently loads the same package twice using different module systems. This resulted in extremely hard-to-track runtime bugs, such as duplicate singleton instances, corrupted global state, or multiple database connections.

The stabilization of require(esm) in Node.js 24 is the key to solving this. Even if a library is distributed solely as a pure ESM package, a CommonJS backend can now invoke it directly and synchronously. Because it is evaluated and loaded as a single module instance, bugs caused by duplicate singleton objects are prevented at the source.

As a result, complex build pipelines and tsconfig.json configurations are drastically simplified. Maintainers no longer need to deal with tricky conditional exports in bundlers or the waste of dual-compiling CJS and ESM versions. Enterprise development teams can also freely adopt pure ESM libraries into production without the stress of managing hybrid builds and bundling.

Practical Checklist for 2026 Backend Migration

To transition safely to a pure ESM backend, you must first migrate your runtime environment to Node.js 24 (where require(esm) is stabilized) or an LTS version with the backport, such as Node.js 22.12.0+ or 20.19.0+.

Next, update your TypeScript configuration by changing the module and moduleResolution options to NodeNext and apply the rule of explicitly specifying the .js extension at the end of all local import paths. To replace __dirname and __filename, which are unavailable in ESM environments, make minor code adjustments to use import.meta.url instead.

Now is the perfect time to modernize your backend module architecture, as you can finally strip away complex dual-build configurations and simplify your compiler toolchain.

Reference Links