# Node.js Skills Test and Verified Node.js Score > A Node.js skills test built on backend scenarios, plus live sessions on APIs and async code and connected GitHub repos. See what proves Node.js skills. Source: https://getlemma.io/skills/nodejs Node.js looks easy until a service stalls under load or leaks memory overnight. Lemma builds your Node.js record from live sessions, adaptive assessments and code you connect, so the evidence reflects how you handle the hard parts. How Node.js is assessed Preparing for an interview? [Node.js interview questions, junior to senior](https://getlemma.io/skills/nodejs/interview-questions) ## What Node.js competence looks like A capable Node.js developer understands the event loop well enough to predict what blocks it. They keep CPU-heavy work off the main thread, handle promise rejections deliberately and never leave an error unlogged. They structure an API so routes stay thin and business logic is testable without a running server. In production terms, they know how to read a heap snapshot, stream large payloads instead of buffering them, and set timeouts on every outbound call. They pick dependencies carefully, keep secrets out of the repository and can explain how their service behaves when a database or downstream API is slow. ### Event loop and async I/O Predicting what blocks the loop, and using promises, async/await and worker threads appropriately. ### Error handling Catching rejections, propagating errors with context and failing loudly instead of silently swallowing problems. ### HTTP APIs Designing routes, middleware and validation with Express, Fastify or similar, keeping handlers thin and testable. ### Streams and buffers Processing files and responses as streams, handling backpressure and avoiding loading everything into memory. ### Performance and memory Profiling CPU, reading heap snapshots and finding leaks caused by closures, caches or listeners. ### Security basics Input validation, dependency hygiene, secret handling and protection against injection and prototype pollution. ## What counts as evidence of Node.js skills? A line on a CV saying Node.js is a claim. A reviewed session, an assessed level or a repository linked from your account is evidence. These are the kinds Lemma records against your Node.js skill, each with where it came from. See the [evidence methodology](https://getlemma.io/methodology#evidence-types) for how each source is weighed. [Live session](https://getlemma.io/product/sessions) ### Building an API endpoint live With a practitioner watching, you add an endpoint with validation and error handling to a small Node.js service. They rate how you structure it and how you reason about failure cases. [Adaptive assessment](https://getlemma.io/product/assessments) ### Event loop and async scenario questions Adaptive multiple-choice questions test callback ordering, promise behaviour and error propagation. Some show async code and ask which diagnosis is correct. Harder questions count for more. [GitHub connector](https://getlemma.io/product/passport) ### A service or tool on GitHub Connect a repository for an API, a CLI or a library you built in Node.js. Lemma confirms the repository exists and that your account has access, and re-checks it over time. [Vercel connector](https://getlemma.io/product/passport) ### A deployed Node.js backend If your API or server functions run on Vercel, connect the deployment. It shows the code made it to a running environment, not just a local branch. ## How is a Node.js skills test run on Lemma? The Node.js test runs 15 to 25 questions and adjusts difficulty to your answers, with scenarios from services under real load. The result counts alongside sessions and linked repositories toward your Node.js SCI, which favours recent evidence over old. [How the SCI score is calculated](https://getlemma.io/product/sci)[How adaptive skills assessments work](https://getlemma.io/product/assessments)[Practise Node.js in live skill swap sessions](https://getlemma.io/product/sessions)[Which evidence types count](https://getlemma.io/methodology#evidence-types)[What your Skills Passport shows](https://getlemma.io/product/passport) 1. ### Drill async patterns Use the AI tutor to practise promise chains, async iteration and stream handling. Exercises adapt to your answers and reject rushed copy-paste attempts. Drills feed only a small, capped part of your practice score. 2. ### Review a service with a peer In a live session, walk a practitioner through a Node.js service: how requests flow, where errors go and what happens under load. Their rating of that session is recorded against Node.js. 3. ### Pass the adaptive assessment Answer scenario questions on the event loop, modules and error handling. Some show async code and ask you to pick the right diagnosis. Failed attempts lower your proof score slightly, so it pays to prepare first. ## Node.js skills: common questions ### How do I show Node.js backend experience without a job title that says backend? Evidence carries more weight than a title. Build or review a Node.js service in live sessions with a practitioner, pass the adaptive assessment, and connect a repository or Vercel deployment you worked on. Your Skills Passport then shows the backend work itself, whatever your last role was called. ### What Node.js topics come up in technical interviews? Interviewers often probe the event loop, error handling in async code, streams, and how you would find a memory leak. They also ask how you structure an API and handle slow dependencies. Lemma's sessions and assessment cover the same ground, so preparing for one prepares you for the other. ### Do I need TypeScript to prove Node.js skills? No. You can build Node.js evidence in plain JavaScript. Many teams now write Node.js in TypeScript, though, so if you do, consider building evidence for the TypeScript skill too. Each skill keeps its own record, which makes the combination visible on your Passport. ### Does a deployed project count more than a GitHub repository? They show different things. A connected repository shows code you wrote; a connected Vercel deployment shows it runs somewhere. Both count as external proof, which is capped so connected artifacts cannot outweigh live sessions and assessments. The strongest Node.js record combines all of them. ## Skills related to Node.js [Browse the skills directory](https://getlemma.io/skills) [### JavaScript Evidence that you understand how JavaScript runs, not just how to write its syntax. Evidence for JavaScript](https://getlemma.io/skills/javascript)[### TypeScript Show that your types catch real bugs instead of just silencing the compiler. Evidence for TypeScript](https://getlemma.io/skills/typescript)[### GraphQL Show how you design GraphQL schemas and resolvers that stay fast and safe. Evidence for GraphQL](https://getlemma.io/skills/graphql)[### Docker Show you can build small, secure images and debug containers when they misbehave. Evidence for Docker](https://getlemma.io/skills/docker) ![Painting of an olive grove in soft sunlight with hills beyond](https://cdn.sanity.io/images/islu4peo/production/613eb3f93566423c9adf45246f2cf1a61437c04c-1680x1120.jpg?w=1080&fm=webp&q=68&fit=max) ## Start your Node.js evidence record. Lemma is in early access. Request an invite and we will email you when your place is ready.