Short Answer
Stop hiring based on gut feeling. The exact 90-minute technical interview structure to vet senior engineers, complete with scoring rubrics and red flags. It gives buyers a direct answer, clarifies the business problem, and points them to the next page in the decision path without forcing them through vague marketing copy..
The 90-Minute Technical Vetting Playbook for SaaS Teams (2026)
Quick Answer: Interview Structure by Role Level
| Role level | Interview approach | Duration |
|---|---|---|
| Junior (0–2 years) | Practical coding task + culture/communication | 60 minutes |
| Mid-level (3–5 years) | Practical task + basic system design | 75 minutes |
| Senior (5–8 years) | Deep dive + practical task + system design | 90 minutes |
| Tech lead / Staff | Architecture discussion + leadership scenarios | 90–120 minutes |
| First engineer hire | All of above + "build something small" async | 90 min + async |
Skip LeetCode. Abstract algorithmic puzzles select for interview-practice, not SaaS engineering quality. Use practical tasks that mirror the actual job: debug a React hook, design a database schema for a feature you described.
Who Is This Guide For?
| If you are... | Focus on |
|---|---|
| Founder hiring first engineer | Full 90-min playbook + red flags section |
| Engineering manager, building a team | Phase 1 (deep dive) + scoring rubrics |
| Recruiter screening technical candidates | Phase 4 (soft/culture) + red flags |
| CTO creating a hiring process | Full playbook + scoring rubric |
Hiring the wrong engineer costs a SaaS company roughly $50,000 to $100,000 in lost time, recruiting fees, and technical debt. Yet, most companies still rely on unstructured chats or irrelevant whiteboard puzzles.
At Moydus, we use a rigorous 90-minute protocol to vet top 1% talent. This isn't about trick questions; it's about simulating the actual job.
The 90-Minute Agenda
| Time | Phase | Focus |
|---|---|---|
| 00:00 - 00:20 | Phase 1: Deep Dive | Verifying depth of past experience |
| 00:20 - 01:00 | Phase 2: Practical Task | Real-world problem solving (Live) |
| 01:00 - 01:20 | Phase 3: System Design | Architecture & Scalability thinking |
| 01:20 - 01:30 | Phase 4: Culture/Soft | Communication & Team fit |
Phase 1: The "Deep Dive" (20 Minutes)
Goal: Detect 'Passenger' vs. 'Driver' behavior.
Don't ask: "Tell me about your background." Ask: "Pick the most complex system you built in the last 2 years. Draw the architecture. What was the single hardest technical constraint you faced, and how specifically did you solve it?"
What to look for:
- Drivers explain trade-offs (e.g., "We chose Postgres over Mongo because we needed ACID compliance for transactions...").
- Passengers explain events (e.g., "We used React because that's what the team was using.").
Phase 2: The Practical Task (40 Minutes)
Goal: Assess coding fluency and debugging skills.
Rule #1: No LeetCode. Reversing a binary tree on a whiteboard proves nothing about building a SaaS product.
The Task: Provide a realistic, slightly broken code snippet (e.g., a React component with a useEffect infinite loop or a Node.js API endpoint with a race condition).
The Prompt: "Here is a piece of code that is failing in production under high load. Talk me through how you would debug this, and let's refactor it together."
Scoring Criteria:
- Tooling: Do they use the debugger/console effectively?
- Communication: Do they explain their thought process out loud?
- Safety: Do they consider edge cases (null checks, error handling)?
- Modern Syntax: Are they using 2026 standards (e.g., TS 5.x features)?
Phase 3: System Design (20 Minutes)
Goal: Test ability to scale and architect.
The Prompt: "Design a simplified version of Slack's real-time messaging system."
Key Checkpoints:
- Database: Do they suggest a suitable DB (e.g., Cassandra/DynamoDB for messages)?
- Real-time: Do they mention WebSockets?
- Scale: How do they handle 1 million concurrent users? (Load balancers, sharding, caching strategies).
- Trade-offs: Do they acknowledge the cost/complexity of their choices?
Phase 4: Cultural & Communication Fit (10 Minutes)
Goal: Ensure they raise the bar for the team.
The "No Jerks" Rule: Even a 10x engineer will destroy a startup if they are toxic.
Key Questions:
- "Tell me about a time you disagreed with a Product Manager or Designer. How did you resolve it?"
- "How do you handle code reviews? Give me an example of feedback you gave recently."
The Scoring Matrix
We score every candidate on a 1-5 scale across 4 dimensions. A candidate must average 4.0+ to receive an offer.
| Dimension | Description | Weight |
|---|---|---|
| Technical Proficiency | Quality of code, speed, knowledge of stack | 40% |
| Problem Solving | Ability to break down ambiguous problems | 30% |
| Communication | Clarity, English fluency, documentation | 20% |
| Culture Add | Mentorship potential, attitude, curiosity | 10% |
Conclusion
The goal of this interview is not to find a candidate who knows everything. It is to find a candidate who can learn anything, communicate clearly, and build maintainable software.
If you need help vetting talent or want to bypass this process entirely, Moydus provides pre-vetted, managed engineering teams ready to deploy in days.
The Problem
- Skip LeetCode for SaaS hiring. Abstract algorithmic puzzles select for interview practice, not product engineering quality. Practical tasks — debug this React hook, design a schema for this feature — reveal actual ability.
- The 90-minute structure: 20 min architectural discussion, 40 min practical coding (pair programming style), 30 min experience and judgment. Candidates who can't explain trade-offs clearly under mild pressure won't do it under product pressure either.
- The single most predictive interview signal: how a candidate responds to pushback on their design choices. Senior engineers defend with reasoning and update with new data. Juniors either capitulate immediately or become defensive.
The Solution
Moydus uses The 90-Minute Technical Vetting Playbook for SaaS Teams (2026) to explain the decision clearly, connect the topic to real use cases, and move readers toward the next practical step instead of generic education.
How It Works
- Define the exact question the page needs to answer.
- Translate the answer into plain language, examples, and decision criteria.
- Route readers to a comparison or service page when they move from learning to evaluation.
Expected Result
The reader gets a direct answer, understands the tradeoffs faster, and has a clear path to the next relevant page instead of bouncing after the first scan.
Proof
- "The old version looked polished, but people still asked what we actually offered. The revised page made the value obvious and the calls were easier to close."
- Case-style outcome: teams usually use this page structure to reduce buyer confusion, improve lead quality, and route visitors to the right next page faster.
FAQ
How long should a technical interview be?
For senior roles, 90 minutes is the gold standard. It allows enough depth for architectural discussion (20m), practical coding (40m), and experience verification (30m).
Should we use LeetCode style questions?
Avoid abstract algorithmic puzzles (LeetCode) for general SaaS hiring. Instead, use 'practical pair programming' tasks that mirror daily work, like debugging a React hook.
What are the red flags in a technical interview?
Major red flags: Inability to explain trade-offs (e.g., SQL vs NoSQL), defensive attitude when challenged, lack of curiosity about the 'why', and poor communication.
Internal Links
- Hub page: Learn Hub
- Spoke page: Comparison Page
- Spoke page: Case Study
- Commercial page: Contact Moydus