Modern.js: ByteDance's progressive React framework and its Rspack family

Progressive, with ByteDance's production numbers behind it

The Modern.js framework is a progressive web framework based on React, and the introduction grounds the claim in scale, at ByteDance, Modern.js is used to build upper-level frameworks that have supported the development of thousands of web applications. The problem statement follows the familiar React experience, developers usually need to design implementation plans for certain features or use other libraries to solve them, and Modern.js supports all configurations and tools needed by React applications with built-in additional features and optimizations. The progressive mechanism is explicit, developers use React to build the UI, then gradually adopt Modern.js features to solve common application requirements, routing, data acquisition and state management, the three layers that turn a React app into a framework-managed application without a rewrite.

The Rspack family, four siblings

The ecosystem section names the four tools around the framework, each with its own project. Rspack is a fast Rust-based web bundler. Rsbuild is an Rspack-based build tool for the web, rebranded from Modern.js Builder, the extraction of the framework's build layer into a standalone product. Rspress is a fast Rspack-based static site generator, and Rslib is an Rspack-based library development tool. The relationship matters for evaluation, Modern.js sits on this foundation rather than webpack, so its build performance story is Rspack's, and the rebranding note tells where the boundaries moved, the builder became a product of its own, and the framework consumes it.

Benchmarks, roadmap, examples

Three sections show how the project manages itself. The benchmark page, Modern.js Benchmark, observes trends of key metrics, bundle size, compile speed and install size, published rather than asserted. The roadmap lives in a GitHub issue, updated regularly, unusual transparency for tracking a framework's direction. And the examples are a separate repository, modern-js-examples, holding ready-to-use projects, with the in-tree examples directory showing the deployment and integration shapes the team tests, basic with Zephyr, deploy, CSR and SSR deploy variants, module federation, react compiler, server-sent events, storybook, and the three test runners, cypress, jest and playwright, beside vitest. Each example doubles as documentation of a supported configuration.

Credits, and the lineage of its pieces

The credits section is unusually specific about ancestry, some implementations of Modern.js are modified from existing projects, create-react-app, remix, jest and bundle-require, with thanks. The package-level attributions name the lineage, bundle-require modified from egoist's bundle-require, the plugin hooks API referenced from farrow-pipeline, the data-loader plugin referencing code from remix, and the babel module resolver modified from tleunen's. For an adopter, this maps the framework's capabilities to their provenance, the data loading story descends from Remix's loaders, the plugin system from farrow's pipeline hooks, and the credits close with Netlify for hosting the site. The MIT license with a THIRD-PARTY-LICENSE file completes the legal hygiene.

A pnpm, Nx and changesets monorepo

The repository is a pnpm workspace orchestrated by Nx, and the scripts reveal the scale, prepare-build runs nx run-many building all at-modern-js packages with a max parallelism of four, excluding the two documentation packages, and build:required names the five packages every other depends on, builder, bff-core, utils, i18n-utils and runtime-utils. Testing splits into framework and builder integration suites in a tests directory plus unit tests through rstest, the team's own Rspack-based test runner, and lint is biome. Releases flow through changesets with pre-enter and pre-exit modes for release candidates, husky for hooks, and a prepare script chaining the build. The monorepo machinery is sized for the dozens of published packages the framework comprises.

Weekly releases, bilingual docs

The release train moves weekly, v3.9.1 on September 11, v3.9.2 on September 17 and v3.9.3 on September 24, 2026, with the repository pushed the same week, and the documentation is bilingual with English and simplified Chinese readmes and a docs site at modernjs.dev. The community lives on Discord with the team and users active, contributions welcome through the contributing guide under the ByteDance Open Source Code of Conduct, and AGENTS.md plus CLAUDE.md at the root configure coding agents for contribution. The homepage, npm package at at-modern-js/core and npm-compare badge complete the public surface of a framework maintained as infrastructure rather than a side project.

Editorial conclusion

Use Modern.js when starting a React application that should grow from simple to full-featured within one framework, progressively adopting routing, data loading and BFF capabilities, and when ByteDance-scale production validation matters. Prefer plain Vite or Rsbuild with hand-picked libraries when you want minimal framework commitment. Before adopting, read the Quick Start for the project scaffolding, browse the ready-to-use examples repository for your deployment shape, and note the relationship to its sibling tools, Rsbuild is the build layer rebranded from Modern.js Builder, so framework and tooling versions move together but document separately.

Frequently asked questions

Official sources

1. Official documentation
2. Official README
3. Project repository
4. Release notes