What to assess in a Node.js developer
Node.js roles reward people who understand the event loop and who think about the failure path as carefully as the happy one.
- Async behaviour: promises, concurrency limits, and what blocks the event loop.
- API design: routes, status codes, validation, pagination and versioning.
- Data access: queries, transactions, indexes and avoiding N+1 patterns.
- Errors and observability: handling, logging and surfacing failures without leaking details.
- Security: input validation, authentication, secrets and dependency risk.
- Working with AI: asking for edge cases and tests, not only the happy path.
Screening questions for Node.js candidates
When a section calls for code, a TypeScript workspace on Node opens beside the conversation. When the candidate sends an answer, the server reruns their tests; a pass reported by the browser is thrown away.
- An endpoint is fast locally and times out in production under load. What do you check?
- Write a function that fetches a list of URLs with at most three requests in flight at once.
- How do you make a payment webhook safe to receive twice?
- An assistant writes a route that builds SQL by joining strings. What do you change?
- How do you stop one slow downstream service from taking your API down with it?
The Node.js coding round
The round opens a Node.js service with starter files and tests in a Cursor-like IDE: Monaco, a terminal, completions, file-aware chat and an agent. Guarded mode tests fundamentals with a limited helper; unguarded mode tests how they ship with a full assistant. The server enforces it.
Every line is tinted by who wrote it. The server reruns the tests when the round ends, and you can review the change as a diff with line comments.
AI-fluency signals for a Node.js developer
| Signal | What it tells you about a Node.js developer |
|---|---|
| Time to first prompt | Whether they read the service's routes and tests before asking for code. |
| Prompt quality | Whether prompts name the endpoint, the input and the failure cases. |
| AI-generated share | How much of the final handler or module came from accepted AI output. |
| Verification | Whether they ran the tests in the terminal soon after accepting code. |
| Over-reliance flags | Large accepted blocks, such as a whole data layer, never reviewed or tested. |
| Recovery | What they did when generated code failed a test or mishandled an error. |
From scores to a decision
Fundamentals and AI fluency are scored separately, and a score without a real answer or edit behind it is reported as a gap. The recommendation is advice. A named person signs off every round and records the outcome.
Questions
Does the AI screen run real Node.js code?
Yes. The screen's code workspace is TypeScript on Node, and the server reruns the candidate's tests when they send an answer.
What does the Node.js coding round include?
A real Node.js service with starter files and tests, a terminal, and an AI assistant with completions, chat and an agent, at the level of help you choose.
Can I assess database skills?
Yes, in conversation and through the task you set. The screener asks about queries, transactions and indexes if they are in your plan.
How long does a Node.js coding round take?
You set the length. A coding round's price covers up to 90 minutes, and the clock runs from the start without pausing.