relysjs

1.21.76 verified Fri May 01 auth: no javascript

relysjs is a reactive web app server focused on multi-page applications (MPAs). Current stable version is 1.21.76. It integrates Bun, Elysia, ESBuild, rmemo, and ctx-core to provide a simple server route and browser build API. Release cadence is frequent with regular updates. Differentiators include native Bun support, reactive server-side rendering, and a unified server + build pipeline with ESBuild. It simplifies MPA development by combining routing, bundling, and reactivity in a single coherent framework.

Common errors

error Error: Cannot find module 'esbuild' ↓

cause esbuild is not installed as a peer dependency.

fix

Install esbuild: bun add esbuild

error TypeError: relysjs is not a function ↓

cause Using incorrect import form (commonjs require).

fix

Use ESM import: import relysjs from 'relysjs'

error Error: 'buildLib' is not exported from 'relysjs' ↓

cause Importing from the wrong path.

fix

Import from 'relysjs/server' instead.

Warnings

breaking Drop support for Node.js < 20; requires Bun runtime. ↓

fix Use Bun v1.0+ as your JavaScript runtime.

deprecated The `serve` property is deprecated; use `routes` instead. ↓

fix Replace `serve` with `routes` in config.

gotcha All imports must be ESM; require() will throw. ↓

fix Use import syntax or set type: module in package.json.

Install

npm install relysjs

yarn add relysjs

pnpm add relysjs

Imports

relysjs

wrong

const relysjs = require('relysjs')

correct

import relysjs from 'relysjs'

ESM-only package; require will fail.

Route

wrong

import Route from 'relysjs'

correct

import { Route } from 'relysjs'

Named export; do not use default import.

buildLib
wrong
```
import { buildLib } from 'relysjs'
```
correct
```
import { buildLib } from 'relysjs/server'
```
Server-specific utilities are exported from subpath 'relysjs/server'.

Quickstart

Creates a minimal MPA server with a single route and ESBuild client bundling config.

import relysjs from 'relysjs';

export default relysjs({
  routes: [
    {
      path: '/',
      handler: async () => {
        return `<html><body><h1>Hello, relysjs!</h1></body></html>`;
      }
    }
  ],
  build: {
    entryPoints: ['./client.js'],
    outdir: './public'
  }
});

// Run with: bun run relysjs.config.ts