How do you mentor an eager junior who is still learning full-stack fundamentals?

A good progression would be: HTTP and browser basics, JavaScript and React data flow, making requests to a public API, creating a small backend endpoint, connecting it to a database, handling errors and environment variables, writing a few tests, and finally deploying the smallest working version. At each stage, have them explain the data flow in plain language and make a small change themselves. The goal is not to provide a long list of tutorials, but to pair each topic with a concrete task they can troubleshoot.

Be careful about labeling these topics as obvious fundamentals. API integration, environment configuration, and deployment may be routine for an experienced web developer but can be completely new to an intern, especially if this is their first professional role. Set expectations based on how long they’ve been learning and working, then teach the concepts directly instead of assuming a lack of ability or effort. Documentation tasks, small tests, and explaining an existing feature can also build confidence before they own a complete deployment.

Start with a very small vertical slice instead of asking them to understand the whole stack at once. For example: build a React form, send a POST request to one API endpoint, validate the input on the server, save one record, return a response, display it in the UI, and deploy that exact flow. Keep the architecture simple and avoid adding authentication, elaborate abstractions, or extra services until the basic path works. Have them draw the request flow first so they can explain what happens from the browser to the server and back.

Make questions more structured and limit unscheduled one-on-one help. Set regular office hours and ask them to bring a short debugging note: what they expected, what actually happened, the exact error or relevant logs, what they tried, and two possible explanations. This encourages independent investigation while still giving them a safe way to ask for help. It also turns “everything broke” into a focused problem you can solve together.

Give them ownership of the project documentation and a simple learning checklist. Ask them to document how to run the app, where configuration values come from, how the frontend reaches the backend, how to reproduce common errors, and how deployment works. Writing those steps exposes gaps in understanding and creates something useful for the team. You can review the documentation during scheduled sessions rather than repeatedly answering the same questions.