Your technical interview process is simultaneously your quality filter and your candidate experience. Get it right, and you hire excellent engineers who rave about the experience. Get it wrong, and you either hire poorly or lose great candidates to competitors with better processes. After facilitating thousands of IT placements across our permanent staffing and contract hiring services, we have seen what works, what fails, and what drives candidates to withdraw. Here is a comprehensive guide.
Designing Your Interview Pipeline
Before evaluating a single candidate, design the overall pipeline. The best technical interview processes share three characteristics:
- They are structured. Every candidate goes through the same stages, evaluated against the same criteria. Ad hoc interviewing leads to inconsistent decisions and legal risk.
- They are time-bounded. The entire process — from first screen to offer — takes no more than 2 weeks. Every additional week of delay increases candidate dropout by 10-15%.
- They evaluate what the job requires. If the role is building REST APIs, test API design — not binary tree algorithms from a textbook.
A recommended pipeline for most IT roles:
- Stage 1: Recruiter screen (30 min) — Assess motivation, salary expectations, logistics
- Stage 2: Technical assessment (60-90 min) — Coding test or take-home assignment
- Stage 3: Technical interview (60 min) — Deep-dive on technical skills with an engineer
- Stage 4: System design (45-60 min) — For mid-senior roles; whiteboard architecture discussion
- Stage 5: Hiring manager conversation (45 min) — Culture fit, career goals, team dynamics
- Decision and offer within 48 hours of the final round
Stage 1: The Recruiter Screen
The recruiter screen is often treated as a formality. It should not be. This stage serves three critical functions:
1. Qualify the candidate. Verify that the candidate’s experience, salary expectations, and availability align with the role. Discovering a mismatch after three rounds of technical interviews is wasteful.
2. Sell the opportunity. Top candidates are evaluating you as much as you are evaluating them. Use this stage to share what makes the role and team compelling.
3. Set expectations. Explain the interview process, timeline, and what each stage will cover. Candidates who know what to expect perform better and feel more positive about the experience.
Stage 2: Technical Assessment
This is where most interview processes make their first mistake. The assessment should be relevant, respectful of the candidate’s time, and predictive of on-the-job performance.
Option A: Timed coding test (60-90 minutes)
Platforms like HackerRank, Codility, and LeetCode provide standardised coding assessments. These work well for screening large volumes of candidates and establishing a baseline technical bar.
Best practices:
- Limit to 2-3 problems of varying difficulty
- Focus on practical problem-solving, not obscure algorithms
- Allow the candidate’s preferred programming language
- Set a reasonable time limit (90 minutes maximum)
- Review not just whether the solution passes test cases, but the code quality, edge case handling, and approach
Common mistakes:
- Using puzzle-style problems that test trivia, not engineering skill
- Setting time limits too tight, disadvantaging candidates who think carefully before coding
- Requiring specific languages that are not used in the actual role
Option B: Take-home assignment (3-5 hours, 2-3 day deadline)
A take-home assignment asks candidates to build something that resembles real work. This approach better evaluates practical engineering skill, code organisation, and technical decision-making.
Best practices:
- Scope the assignment to 3-5 hours of work — anything more is disrespectful of the candidate’s time
- Provide clear requirements, evaluation criteria, and a deadline (2-3 days is reasonable)
- Allow candidates to use any tools, libraries, or references they normally use (this simulates real work)
- Evaluate: code quality, test coverage, documentation, architecture decisions, and edge case handling
- Provide written feedback on the submission, regardless of the outcome
Common mistakes:
- Assignments that take 10+ hours (candidates with families or current jobs will withdraw)
- Vague requirements that leave candidates guessing what you want
- Never providing feedback on rejected submissions (this damages your employer brand)
Stage 3: Technical Interview
The live technical interview is where you assess depth. This is not a repeat of the coding test — it is a conversation between engineers.
Structure:
- First 10 minutes: Build rapport. Ask about their current role, what they enjoy, what they are looking for. This reduces anxiety and produces better signal.
- Next 35-40 minutes: Technical deep-dive. Options include:
- Live coding: Give a problem and work through it together. Focus on thought process, communication, and debugging approach — not just the final answer.
- Code review: Present a piece of code with issues and ask the candidate to identify problems, suggest improvements, and discuss trade-offs.
- Technical discussion: Deep conversation about the candidate’s past projects, architecture decisions, and technical challenges they have navigated.
- Last 10 minutes: Candidate questions. The quality of a candidate’s questions reveals as much as their answers.
What to evaluate:
- Problem decomposition: Can they break a complex problem into manageable pieces?
- Communication: Can they explain their thinking clearly?
- Technical depth: Do they understand the “why” behind their choices, not just the “what”?
- Learning orientation: When they hit a wall, do they get stuck or explore alternatives?
Stage 4: System Design Interview
For mid-level to senior roles, the system design interview is essential. It evaluates architectural thinking, trade-off analysis, and the ability to design systems that work at scale.
How to structure it:
- Present the problem (5 min): “Design a URL shortening service” or “Design the backend for a food delivery app.” Use problems relevant to your domain when possible.
- Requirements gathering (10 min): Strong candidates ask clarifying questions: expected scale, latency requirements, consistency vs availability trade-offs, budget constraints.
- High-level design (15 min): The candidate sketches the major components, data flow, and API design.
- Deep-dive (15 min): Pick one or two components and explore them in detail. How would the database be sharded? How would you handle concurrent requests? What happens when this service goes down?
- Discussion (10 min): Talk about monitoring, deployment, and evolution of the system over time.
Evaluation criteria:
- Can they make and justify trade-offs (SQL vs NoSQL, monolith vs microservices, consistency vs availability)?
- Do they consider non-functional requirements (scalability, reliability, security, cost)?
- Can they estimate capacity and make back-of-the-envelope calculations?
- Do they think about operational concerns (monitoring, alerting, deployment, rollback)?
Stage 5: The Hiring Manager Conversation
This final stage evaluates cultural fit, career alignment, and team dynamics. It is not a technical evaluation — the technical bar should be cleared before this stage.
Key areas to explore:
- Motivation: Why are they looking for a change? What excites them about this role?
- Work style: How do they prefer to collaborate? How do they handle disagreements? How do they manage their time?
- Career goals: Where do they see themselves in 2-3 years? Does your company’s growth trajectory align with their ambitions?
- Values alignment: How do they approach code quality? How do they handle production incidents? What does ownership mean to them?
Building Evaluation Rubrics
Every interviewer must evaluate candidates against a pre-defined rubric, not gut feeling. A simple rubric for each stage:
Rating scale (1-5):
- Does not meet the bar
- Below expectations for the level
- Meets expectations
- Exceeds expectations
- Exceptional — top 5% of candidates at this level
Each stage should have 4-6 specific criteria with descriptions of what each rating looks like. For example, for a coding interview:
- Problem solving: 1 = Could not make progress. 3 = Solved with hints. 5 = Solved efficiently with clean approach.
- Code quality: 1 = Unreadable, no structure. 3 = Functional with reasonable structure. 5 = Production-quality with edge cases handled.
- Communication: 1 = Could not explain approach. 3 = Explained when asked. 5 = Proactively narrated thinking throughout.
Common Anti-Patterns to Avoid
1. The marathon process. Six rounds over four weeks tests patience, not skill. Three to four stages completed within two weeks is the target. Our guide on cutting hiring time from 90 days to 2 weeks covers how to compress the timeline without sacrificing quality.
2. Algorithm hazing. Asking a backend engineer to implement a red-black tree from memory is not evaluating job-relevant skills. It is hazing.
3. The unprepared interviewer. An interviewer who has not read the candidate’s resume or prepared their questions wastes everyone’s time and signals disrespect.
4. The panel ambush. Five interviewers in a room interrogating one candidate is intimidating, not insightful. One-on-one or two-on-one produces better signal.
5. Ghosting rejected candidates. Every candidate who interviews deserves a timely, respectful rejection. Ghosting destroys your employer brand in a community where engineers talk to each other.
Continuous Improvement
Track these metrics to improve your interview process over time:
- Candidate pass-through rate at each stage: Identify where the funnel is too narrow or too wide
- Candidate dropout rate: If candidates are withdrawing at a specific stage, investigate why
- Offer acceptance rate: Low acceptance rates suggest a problem with the candidate experience or compensation
- New hire performance at 6 months: Correlate interview scores with on-the-job performance to validate your rubrics
- Interviewer calibration: Regularly calibrate interviewers to ensure consistent evaluation standards
At StakTeck, we coach our clients on interview process design as part of our executive search and niche recruitment engagements. A great interview process is a competitive advantage — it attracts better candidates and produces better hiring decisions.
Related Reading
- How to Write Job Descriptions That Attract Top IT Talent — A compelling job description is the foundation of a strong interview pipeline
- How to Cut Your Tech Hiring Time from 90 Days to 2 Weeks — Practical tactics to compress your hiring timeline
- Our Process — See how StakTeck’s structured screening methodology delivers quality hires fast
