How cache works in Next.js with the Pages Router?
Interviewer Expectations for this Question
01
Core Competency
Assesses fundamental understanding of Next.js conventions, runtime behavior, and memory/performance considerations.
02
Evaluation Criteria
Hiring managers look for precision, avoidance of ambiguous jargon, and ability to explain trade-offs under real production conditions.
Comprehensive Model Answer
Verified Solution
Next.js uses a built-in caching mechanism for static assets and API routes. You can also implement custom caching strategies using HTTP headers or libraries like next-cache.
- Static Assets: Cached by default with a long cache lifetime.
- API Routes: Can be cached using HTTP headers like
Cache-Control.
export default function handler(req, res) {
res.setHeader("Cache-Control", "public, max-age=3600, immutable");
res.status(200).json({ message: "Cached response" });
}
Candidate Response Strategy & Interview Tips
- Start with a concise one-sentence summary: Deliver a direct, confident answer first before expanding into nuances.
- Demonstrate real-world trade-offs: Discuss where this approach excels and when you would avoid it in production systems.
- Discuss complexity & edge cases: Proactively explain time/space complexity or boundary conditions (null values, scale limits).
- Prepare for interviewer follow-ups: Technical hiring panels frequently probe deeper into concurrency, backward compatibility, or alternative libraries.