How would you design a REST API for interview topics in Express?

Direct answer

Mount /interviews/topics router with GET list (pagination query), GET :slug detail, validate params, thin controllers calling service layer, JSON errors, express.json middleware, and 404/500 handlers — map same design to Fastify for AceDevHub production.

Scenario: build read-only public API for interview topic pages — mirrors GET /interviews/topics/:slug in AceDevHub.

Routes — GET /interviews/topics, GET /interviews/topics/:slug.
Middleware stack — cors, helmet, rate-limit, express.json (Q42–48).
Service layer — interviewsService.getTopicPage(slug) with pg query.
Errors — 404 unknown slug; 500 with generic message.

scenario-rest-api.mjs

import express from "express";

const app = express();
app.use(express.json());

const router = express.Router();

router.get("/", async (req, res, next) => {
  try {
    const page = Number(req.query.page ?? 1);
    const topics = await interviewsService.listTopics({ page, limit: 20 });
    res.json({ data: topics });
  } catch (err) { next(err); }
});

router.get("/:slug", async (req, res, next) => {
  try {
    const topic = await interviewsService.getTopicPage(req.params.slug);
    if (!topic) return res.status(404).json({ error: { code: "NOT_FOUND" } });
    res.json({ data: { page: topic } });
  } catch (err) { next(err); }
});

app.use("/interviews/topics", router);