How to Prepare for a Developer Technical Interview

Developer technical interviews include coding tests, system design and behavioral rounds. How to prepare for every stage without getting lost.

Software developers in Thailand in 2026 interviewing at large tech companies must pass a multi-round Technical Interview that includes a coding test, system design, behavioral questions and a deep dive into specific technologies. Good preparation covers every stage and knows what each one measures. Candidates who don't prepare fully often fail at the stage they didn't expect to be hard.

The Technical Interview Process Structure

The stages you will meet in a standard process:

Main Stages

1. A 30-minute phone screening with a recruiter
2. A 2 to 4 hour take-home coding assignment
3. A 60 to 90 minute live coding interview
4. A 60-minute system design interview
5. A 45 to 60 minute behavioral interview
6. A final round with leadership

The full process takes 2 to 4 weeks. Good scheduling reduces time off from your current job.

Preparing for Live Coding

Live coding is the most stressful round.

Preparation

• Practise 100 to 200 LeetCode problems over the 2 to 3 months beforehand
• Focus mostly on medium difficulty
• Cover data structures, algorithms and system design topics
• Practise thinking out loud while coding
• Practise with pen and paper for whiteboard interviews
• Do mock interviews with friends

Quality of practice beats quantity: 50 problems you understand deeply are better than 200 problems you jump around.

Preparing for System Design

System design measures your ability to design large-scale systems.

Topics to Cover

• Load balancing and horizontal scaling
• Database design: relational vs NoSQL
• Caching strategies
• Message queues and async processing
• Microservices vs monolith trade-offs
• CAP theorem and consistency models
• Common architectures such as a URL shortener, chat app or news feed

Books to use: Designing Data-Intensive Applications, and System Design Interview by Alex Xu.

Approaching a System Design Question

How to structure your answer:

5 Steps

1. Clarify functional and non-functional requirements
2. Estimate scale: users, requests, storage
3. High-level design: sketch the main components
4. Deep dive into the components the interviewer is interested in
5. Discuss trade-offs and scaling

Practising at least 10 system design problems before the interview makes the patterns start to become clear.

A good technical interview isn't about reaching a perfect answer; it is about showing your thinking and awareness of trade-offs.

Preparing the Take-Home

A take-home assignment takes 2 to 4 hours.

Tips for Doing It Well

• Read the requirements twice before you start coding
• Set a scope you can finish within the time limit; don't over-engineer
• Write tests that cover the critical path
• Include a README explaining your design and trade-offs
• Commit to Git with clear messages
• Review for 30 minutes before submitting

A carefully prepared take-home reflects the quality of your real work.

Handling Behavioral Rounds in Tech

Behavioral rounds in tech aren't very different from other roles, but they focus on engineering-specific topics.

Questions You Will Face

• Describe a challenging project
• Describe technical debt you managed
• Describe a conflict with a teammate over a technical decision
• Describe a time you debugged a complex bug
• Describe a time your design decision was wrong

Use the STAR Method to answer. Read STAR Method.

Linking to Your Career Strategy

The technical interview is the gateway to senior developer careers.

Connect it with General Engineering Interviews and Behavioral Interview.

To practise coding with AI, read Using ChatGPT to Practise Interviews.

Try Career Assistant for mock interviews and developer interview courses in Plants.work Learn. In summary, technical interview prep takes 2 to 3 months of serious effort in exchange for offers with comp 20 to 40 percent higher, which is well worth the investment.