The qualities of a good software engineer go well beyond technical ability. Domain expertise matters, but so does how a developer collaborates, learns, reasons through problems, and sustains quality over time. For hiring managers and engineering leaders evaluating candidates, knowing which qualities to assess — and how to test them — is the difference between a hire that accelerates a project and one that slows it down.
As a custom software development agency that has hired and worked with engineers across many specializations, we have developed a clear view of what separates strong developers from average ones. Below are the 10 qualities we consistently look for, along with practical guidance on how to evaluate each one during the hiring process.
The 10 Key Qualities of a Good Software Engineer
1. Deep expertise in their area of specialization
The most important quality to assess is whether the candidate has genuine, hands-on expertise in the specific area your project requires — not general programming knowledge. If you need a .NET developer, you want someone with a proven track record in .NET specifically, not someone who has worked adjacent to it. The difference in output between a specialist and a generalist on a focused project is significant.
How to test this:
- Ask for work samples and references from previous roles. Even without deep technical knowledge yourself, you can evaluate whether the work looks polished and whether former colleagues speak highly of the candidate’s contributions.
- Use structured technical tests calibrated to the role’s level. A test designed for senior developers applied to a mid-level candidate produces misleading results. Match the assessment to the experience you are actually hiring for.
- If possible, have a senior engineer from your team or network conduct the technical portion of the interview. A direct technical review is the most reliable way to assess depth of expertise.
2. Effective team collaboration with the ability to work independently
Good developers write code that other developers can read and maintain. On larger or longer-running projects, the ability to produce clean, consistent, well-documented code is as important as the ability to write clever code. At the same time, strong engineers are also self-sufficient when a project requires it.
How to test this:
- Ask candidates to describe specific instances where they supported a teammate, unblocked a colleague, or contributed to improving shared code. Listen for concrete examples rather than general statements.
- Present a brief scenario and ask how they would communicate a technical decision to a non-technical stakeholder. How a developer explains complexity reveals a lot about their collaborative instincts.
- Ask whether they prefer working in a team or independently on a given type of task, and why. A candid and specific answer reveals self-awareness about working style.
3. Cultural and professional fit
Technical skill is necessary but not sufficient. A developer who fits well with your team’s working culture, communication norms, and values will contribute more over time than one who does not — even if the latter has stronger raw technical ability. This is not about personal chemistry alone. It is about whether their professional expectations, communication style, and approach to work align with how your team actually operates.
How to test this:
- Involve team members who will work closely with the candidate in at least one interview session. Multiple perspectives reduce the risk of a poor fit going unnoticed.
- Ask the candidate how they prefer to give and receive feedback. A developer who cannot handle code review constructively will struggle in most modern engineering teams.
4. Healthy skepticism and critical thinking
Strong engineers cross-check their own assumptions, question requirements that seem unclear, and look for edge cases before they become production bugs. The best ones can acknowledge that they too make mistakes — and they have built habits to catch those mistakes early rather than relying on others to find them later.
How to test this:
- Present a piece of code with a subtle issue and ask the candidate to review it. Pay attention to whether they propose a durable fix or just a workaround, and whether they ask clarifying questions before diving in.
- Show a code snippet and ask for a time estimate to complete or refactor it. Compare the response to what experienced engineers on your team would say — this reveals calibration and realism.
5. Creative and innovative problem-solving
The best engineers do not just execute known solutions to known problems. They look for better approaches to problems that have already been solved, and they bring original thinking to design decisions. This quality drives improvement across the entire codebase over time and is particularly visible in how engineers approach architecture decisions.
How to test this:
- Give the candidate an open-ended technical problem with more than one valid solution. Evaluate not just whether their answer works, but how they reasoned through the options and why they chose the approach they did.
- Ask how they have improved or simplified something in a previous project. Engineers who bring creative thinking to their work typically have specific, detailed examples ready.
6. Genuine passion for technology
Engineers who are genuinely interested in technology — who follow industry developments, experiment with new tools, and find the craft engaging — stay ahead of the curve without being pushed to. This intrinsic motivation is a strong predictor of both long-term performance and retention. It also means they tend to bring better ideas to projects proactively.
How to test this:
- Ask which technical resources, communities, or publications the candidate follows. Developers who are genuinely engaged typically have specific, thoughtful answers rather than generic ones.
- Ask about a recent technology or framework that has caught their attention and why. The quality and specificity of the answer reflects the depth of their engagement with the field.
- Ask how they approach problems they have never encountered before. Self-directed research and active community participation are good indicators.
7. Strong ability and willingness to learn
Technologies and frameworks evolve quickly. A developer who can pick up new tools, languages, or patterns efficiently is more valuable over a long engagement than one with mastery of a specific stack who struggles to adapt. Learning ability compounds over time: developers who learn well in the early stages of a role tend to grow significantly faster than those who do not.
How to test this:
- Present the candidate with a concept adjacent to their experience and ask them to walk through how they would approach learning it. The process they describe is more revealing than whether they already know the answer.
- Ask about a time they had to learn something quickly under project pressure. Look for self-awareness about how they learn best and concrete examples of what they did.
8. High standards for code quality
Developers who care about code quality ship cleaner, more maintainable, more readable work. They favor simpler solutions over complex ones when both achieve the same outcome, and they treat technical debt as a real cost rather than a future problem for someone else to address. This quality has an outsized impact on team velocity over the life of a project.
How to test this:
- Ask the candidate to show an example of well-written code and explain what makes it good. Then ask for an example of poorly written code — ideally from their own history — and what they would do differently.
- Give a task with two implementation paths: a concise, elegant solution and a longer, less efficient one. Developers who value code quality will naturally gravitate toward the cleaner approach and be able to articulate why.
9. Sustained engagement with the work
Routine tasks are unavoidable in any engineering role. Developers who stay engaged — who maintain quality and attention even when the work is not novel — are considerably more reliable than those who coast through anything repetitive. Sustained engagement is a signal of professionalism and long-term work ethic that becomes especially visible on multi-year projects.
How to test this:
- Ask the candidate what aspects of their previous work they found most meaningful, and how they handled the parts they found less engaging. The honesty and self-awareness in their answer matters more than the specific content.
10. Healthy competitive drive and self-awareness
A developer with a healthy competitive instinct invests in improving their own skills, holds themselves to a consistent standard, and takes ownership of both successes and mistakes. This self-critical awareness prevents complacency and makes peer code reviews more productive for everyone on the team.
How to test this:
- Ask the candidate to describe their main technical strengths and the areas where they know they have room to grow. A developer who cannot identify any weaknesses is likely either not self-aware or not being candid.
- Ask about a difficult technical challenge they have faced, how they handled it, and what they learned from it. Look for accountability and genuine reflection rather than a narrative where everything went smoothly.
Frequently Asked Questions
What are the most important qualities of a good software engineer?
The most important qualities of a good software engineer are deep domain expertise, strong communication and collaboration skills, high standards for code quality, and a genuine capacity to learn. Technical skill is the foundation, but engineers who combine strong technical ability with good judgment, self-awareness, and collaborative instincts consistently deliver better outcomes over the course of a project.
How do you assess a software engineer’s qualities during hiring?
The most effective approach combines structured technical assessment (role-specific tests or code review exercises) with behavioral interview questions that reveal how a candidate has handled real situations. Work samples, references from previous roles, and having a senior engineer participate in the technical interview all provide more reliable signal than general questions about experience.
What separates a great software engineer from an average one?
Great software engineers are distinguished not just by what they know but by how they think. They ask better questions, identify risks earlier, write code that others can maintain, and keep improving without being asked to. They also tend to make the people around them more effective through clear communication, knowledge sharing, and a commitment to the team’s output as well as their own individual contributions.
Should you prioritize technical skills or soft skills when hiring a software engineer?
Both matter, and neither alone is sufficient. A developer with exceptional technical skills but poor communication and collaboration habits will create friction in most team environments. A developer with strong soft skills but insufficient technical depth will struggle to deliver. The most reliable hires combine solid domain expertise with the professional qualities — learning ability, self-awareness, code quality standards — that make them effective contributors over time.
The Bottom Line
Identifying the right software engineer for your project requires looking beyond a resume and a technical test. The 10 qualities above — from domain expertise and code quality standards to learning ability and professional fit — give you a more complete picture of a candidate than technical credentials alone. If a developer demonstrates the majority of these qualities, you have found someone worth investing in.
At unicrew, we build dedicated development teams by applying exactly these criteria. If you are looking for engineers who combine technical depth with the professional qualities that make long-term collaboration work, get in touch to discuss your requirements.