Whether you're a junior developer looking for your first job or a senior engineer switching companies, interview preparation is crucial. After going through multiple interview processes and helping others prepare, here's my complete guide for 2026.
The 4 Pillars of Interview Prep
1. Technical Knowledge
2. Problem-Solving Skills
3. Behavioral Answers
4. Company Research
Let's break each one down.
Pillar 1: Technical Knowledge
Data Structures to Know Cold
- Arrays & Strings — manipulation, two pointers, sliding window
- Hash Maps — O(1) lookups, frequency counting
- Trees & Graphs — BFS, DFS, traversals
- Stacks & Queues — monotonic stack, BFS with queue
- Linked Lists — fast/slow pointers, reversal
Algorithms to Practice
- Sorting — merge sort, quick sort (know time/space complexity)
- Binary Search — on sorted arrays and on answer space
- Dynamic Programming — start with memoization, then tabulation
- Greedy — interval scheduling, activity selection
- Backtracking — permutations, combinations, subsets
System Design (for Mid/Senior)
- Load balancers, caching strategies, database sharding
- CAP theorem, eventual consistency
- Message queues (Kafka, RabbitMQ)
- Microservices vs monolith trade-offs
Pillar 2: Problem-Solving Framework
Use this 5-step approach for every coding problem:
Step 1: Understand — Restate the problem. Ask clarifying questions.
Step 2: Examples — Walk through 2-3 examples, including edge cases.
Step 3: Approach — Describe your strategy BEFORE coding. Mention time/space complexity.
Step 4: Code — Write clean code. Use meaningful variable names.
Step 5: Test — Trace through your solution with the examples. Fix bugs.
Practice Strategy
- Week 1-2: Easy problems (2 per day)
- Week 3-4: Medium problems (1-2 per day)
- Week 5+: Hard problems + mock interviews
Pillar 3: Behavioral Questions (STAR Method)
Every behavioral answer should follow STAR:
- Situation — Set the context (1-2 sentences)
- Task — What was your responsibility?
- Action — What did YOU specifically do?
- Result — Measurable outcome
Top 5 Questions to Prepare
1. "Tell me about yourself"
Framework: Present → Past → Future
"I'm currently a [role] working on [project]. Previously, I [relevant experience]. I'm excited about [this role] because [specific reason]."
2. "Describe a challenging project"
Use STAR. Focus on YOUR contribution, not the team's.
3. "How do you handle disagreements?"
Show empathy + data-driven resolution.
"I listen to understand their perspective, then share data or examples to find the best solution. In one case, [specific example]..."
4. "What's your biggest weakness?"
Pick a REAL weakness + show improvement.
"I used to over-engineer solutions. I've learned to ship MVPs first and iterate based on feedback."
5. "Why do you want to work here?"
Research the company. Be specific.
"I admire [company's specific product/mission]. My experience in [X] directly maps to [job requirement]."
Pillar 4: Company Research Checklist
Before EVERY interview, research:
- [ ] Company mission and values
- [ ] Recent news, product launches, funding
- [ ] Tech stack (check StackShare, GitHub, job posts)
- [ ] The interviewer (LinkedIn)
- [ ] Glassdoor interview reviews
- [ ] Prepare 5 thoughtful questions to ask
Questions to Ask the Interviewer
- "What does a typical day look like for this role?"
- "What's the biggest challenge the team is facing right now?"
- "How do you measure success for this position?"
- "What's the tech stack, and are there plans to evolve it?"
- "What do you personally enjoy most about working here?"
Day-of Checklist
Before
- [ ] Review your notes and STAR stories
- [ ] Test camera, mic, internet (for video)
- [ ] Have water nearby
- [ ] Close distracting apps
During
- [ ] Smile, make eye contact
- [ ] Think for 3-5 seconds before answering
- [ ] Ask clarifying questions
- [ ] Think out loud during coding
After
- [ ] Send thank-you email within 24 hours
- [ ] Note questions you were asked
- [ ] Reflect on what went well and what to improve
Salary Negotiation Tips
- Never give a number first. Say: "I'd love to learn more about the role before discussing compensation."
- Research market rates on Levels.fyi, Glassdoor, Blind
- Negotiate the total package — base, bonus, equity, PTO, remote
- Use competing offers as leverage (but be honest)
- Get it in writing before accepting
Resources
Free
- LeetCode (free tier has 2000+ problems)
- NeetCode.io (curated problem lists)
- Tech Interview Handbook (open source)
Premium
For a complete, ready-to-use interview prep system with 50 questions, STAR templates, salary scripts, and email templates, check out my Job Interview Mastery Kit.
Key Takeaways
- Start preparing at least 2 weeks before your interview
- Practice coding problems daily — consistency beats cramming
- Prepare 5+ STAR stories that cover different scenarios
- Research the company thoroughly — it shows genuine interest
- Negotiate your salary — the first offer is rarely the best one
Good luck with your interviews! What's your best interview tip? Share in the comments.
I'm Daniil, a 19-year-old iOS developer who creates tools for developers and job seekers. Check out my digital products for career guides, AI toolkits, and more.
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