Build, run, and debug backend Node.js and TypeScript microservices directly in your browser. Install any npm package, run Express and Fastify servers, execute Jest test suites, and write code with AI pair programming.
A full server-side runtime equipped with modern package managers, process monitors, and test runners.
Instant syntax checking, type inference, auto-imports, symbol navigation, and JSDoc previews powered by Monaco editor and TypeScript language services.
Full lockfile recognition for package.json, pnpm-lock.yaml, yarn.lock, and package-lock.json. Install packages without downloading gigabytes to your local laptop.
package.json scriptsRun web servers with live reload using nodemon or tsx watch. Test REST and GraphQL endpoints directly from the cloud terminal or browser preview.
Execute unit and integration tests with structured JSON report parsing. Jump straight to failed assertions and test diffs with one click.
Accelerate your API development. Ask the AI agent to write Express routes, validate request payloads with Zod or Joi, generate database migrations, and fix asynchronous race conditions.
Run Node REPL, execute bash scripts, inspect environment variables, manage files, and interact with Git repositories through a persistent shell session.
Write modern TypeScript backend services with schema validation and live logging.
import Fastify from 'fastify';
const fastify = Fastify({ logger: true });
fastify.get('/api/health', async (_req, _reply) => {
return {
status: 'healthy',
runtime: 'Node.js ' + process.version,
uptime: process.uptime(),
timestamp: new Date().toISOString()
};
});
fastify.post('/api/echo', async (req, reply) => {
return reply.status(200).send({
received: req.body,
processedAt: Date.now()
});
});
const start = async () => {
try {
await fastify.listen({ port: 3000, host: '0.0.0.0' });
console.log('Fastify server running in OnlineAIIDE sandbox on port 3000');
} catch (err) {
fastify.log.error(err);
process.exit(1);
}
};
start();Verified runtimes, toolchains, and package managers supported in OnlineAIIDE.
| Capability | Supported Versions & Toolchains | Platform Status |
|---|---|---|
| Node.js Runtime | Node.js 20 LTS (Active), Node.js 18 LTS | Production Ready |
| Package Managers | pnpm 9+, npm 10+, yarn 1.22+ | Production Ready |
| TypeScript Engine | TypeScript 5.x, ts-node, tsx, esbuild | Production Ready |
| Testing Frameworks | Jest, Vitest, Mocha, Supertest | Production Ready |
| Server Frameworks | Express, Fastify, NestJS, Koa, Hono | Production Ready |
Common questions about developing Node.js on OnlineAIIDE.