Technical & Behavioral Interview Cards

Question 1 of 5 Technical Architecture

Recommended Response Strategy

REST operates over stateless HTTP request-response cycles, where the client initiates queries for resources via standard verbs (GET, POST, PUT, DELETE). WebSockets establish a persistent, bidirectional, full-duplex TCP connection over a single socket, ideal for real-time messaging, live collaboration, or trading tickers where polling HTTP would incur high latency.

🎯 What Interviewers Are Evaluating: Evaluating understanding of network protocols, statelessness vs persistent connections, and architectural tradeoffs.

Question 2 of 5 Database & Backend

Recommended Response Strategy

SQL injection happens when untrusted user input is directly concatenated into a SQL string, altering the query syntax. Prepared statements separate query structure from parameters. The database engine compiles and optimizes the SQL template first, treating user-supplied values strictly as data, never as executable code.

🎯 What Interviewers Are Evaluating: Security fundamentals, defensive programming, and PDO/ORM parameterized queries.

Question 3 of 5 State & Frontend

Recommended Response Strategy

The Document Object Model (DOM) is an in-memory tree representation of the HTML document. Because JavaScript is single-threaded, synchronous operations like heavy file I/O or network requests would freeze the main UI thread. Promises and async/await leverage the browser Event Loop to handle non-blocking asynchronous operations smoothly.

🎯 What Interviewers Are Evaluating: Deep JavaScript runtime comprehension, Event Loop, Non-blocking I/O, UI responsiveness.

Question 4 of 5 System Design

Recommended Response Strategy

Session-based authentication stores user session state server-side (in memory, Redis, or MySQL) and issues an opaque session ID stored in an HttpOnly cookie. JWTs (JSON Web Tokens) are stateless, self-contained cryptographic tokens signed by the server. Sessions allow instant server-side revocation, while JWTs reduce database lookups across distributed microservices.

🎯 What Interviewers Are Evaluating: Security architecture, scalability tradeoffs, cookie security (HttpOnly, SameSite, Secure).

Question 5 of 5 Behavioral & Troubleshooting

Recommended Response Strategy

Use the STAR method: Situation (e.g. users experiencing 500 errors during checkout), Task (isolate root cause without downtime), Action (inspected server logs, identified an unhandled null pointer on empty promo codes, reproduced locally in a unit test, applied defensive null-coalescing guard, and verified deploy), Result (error rate dropped to 0%, added regression tests).

🎯 What Interviewers Are Evaluating: Structured problem-solving, composure under pressure, logging discipline, and root-cause analysis.