If you're applying for tech jobs in Ireland, chances are you'll face at least one coding interview. Whether it's a whiteboard session, an online challenge, or a pair programming task, how you perform can be the difference between landing the job or falling short.
Yet, many talented candidates make avoidable mistakes. According to a 2023 report from the Irish Computer Society, over 68% of tech hiring managers said that candidates failed technical interviews due to preventable errors—not lack of core competence.
Below are the top 10 coding interview pitfalls tech professionals in Ireland should watch out for—and, of course, how to avoid them.
1. Jumping Straight into Code Without Clarifying the Problem
Rushing into a solution is a common error. Coding interviews aren’t just about getting the right answer—they’re about showing your process. Always take a moment to clarify the problem. Ask questions like, “What are the constraints?” or “Are negative values possible?”
Irish interviewers, especially in structured interviews, value candidates who take time to scope out the challenge before attempting a solution. It demonstrates analytical thinking and reduces the risk of misinterpreting the task.
2. Not Communicating Your Thought Process
Your ability to solve problems out loud is often just as important as solving them correctly. In pair programming interviews or remote technical screenings, silence can be a red flag. Verbalising your thoughts—why you're choosing a specific algorithm, what trade-offs you're considering—helps the interviewer understand your reasoning and offers them opportunities to redirect or assist.
According to data from a 2022 Stack Overflow hiring survey, candidates who explain their logic clearly have a 25% higher success rate in Irish technical interviews.
3. Overlooking Edge Cases
Neglecting to address edge cases is one of the quickest ways to undermine an otherwise solid solution. In tech interviews, you’re expected to consider not just the happy path, but how your code handles null inputs, large datasets, repeated values, and other anomalies.
Practise asking yourself: “What could break this?” It’s an especially critical skill when applying to fintech, cybersecurity, or medtech firms in Ireland, where system reliability is paramount.
4. Failing to Test Your Code
Writing correct code is step one; validating it is step two. Don’t assume your first solution is flawless. Walk through your logic with sample inputs and discuss expected outputs. If using an online IDE like CoderPad or HackerRank, write a few manual test cases.
Recruiters report that over 40% of rejected candidates could have passed if they’d spent a few extra minutes debugging or testing their solution.
5. Ignoring Time and Space Complexity
In Ireland’s growing tech ecosystem—particularly at high-growth startups and multinationals—performance matters. Interviewers want to see that you understand how your code scales.
Be ready to explain the time complexity (e.g., O(n log n)) and potential optimisations. You don’t need to be a mathematician, but a working knowledge of algorithm efficiency can set you apart. Bonus points if you can suggest a more optimal solution after completing the initial version.
6. Getting Flustered by Mistakes
Interviews are stressful, but your ability to recover from setbacks can make or break your chances. If you hit a wall, don’t panic. Acknowledge the issue, explain what went wrong, and suggest a fix. Interviewers often care more about how you handle adversity than about a perfect solution.
Staying calm under pressure is a highly valued soft skill in Irish tech teams, especially for client-facing roles or positions requiring production support.
7. Using Tools You’re Not Comfortable With
It’s tempting to try impressing an employer by coding in their stack or using a trendy tool, but the interview isn't the place for experimentation. Stick to the programming language you're most fluent in unless instructed otherwise. Your familiarity with syntax, error handling, and built-in libraries can save precious time.
If a firm uses Scala but you're strongest in Python, it's better to write a great solution in Python than struggle with unfamiliar code.
8. Overcomplicating the Solution
Complex solutions aren’t always better. In fact, they often raise concerns about maintainability. Aim for simplicity and clarity in your code. Break it into functions, use meaningful variable names, and avoid “clever hacks” that sacrifice readability.
Many Irish companies, particularly in regulated industries like finance and healthcare, prioritise maintainable code over elegant but cryptic one-liners.
9. Being Unfamiliar with Common Data
Structures and Algorithms Preparation matters. Even if your day job rarely involves writing algorithms from scratch, interviews often do. You’ll frequently encounter tasks involving arrays, linked lists, hash maps, binary trees, and sorting algorithms.
A 2023 LinkedIn Ireland report showed that 57% of tech interviewers include at least one algorithm-based question, regardless of the role’s seniority. Take time to brush up on core CS concepts before you interview.
10. Not Researching the Company’s Tech Stack or Interview Style
Approaching every interview with the same mindset is a mistake. Irish employers expect candidates to tailor their approach. Check if the company uses HackerRank, CoderPad, or in-person whiteboards. Ask the recruiter what to expect. Study the company’s tech blog or GitHub repos.
Knowing whether the team uses JavaScript or Go, or if they favour behavioural questions, can dramatically increase your comfort level on the day.
Bonus Tip: Don’t Neglect Soft Skills
Technical ability is essential, but so is collaboration. Many Irish companies, especially startups, value communication, curiosity, and team fit just as much. Be ready for behavioural questions and demonstrate how you’ve worked through technical challenges with others.
Ireland’s tech sector is vibrant and growing, with more than 135,000 people employed in ICT-related roles as of 2024. But with this growth comes competition. By avoiding these common coding interview mistakes, you can improve your chances of standing out for the right reasons.
Whether you're a graduate looking for your first medtech job in Galway or a mid-career developer targeting a promotion in Dublin, preparation is everything. Focus on clarity, structure, and problem-solving under pressure, and you’ll be in a strong position to impress.
Need help preparing for your next tech interview in Ireland? Contact us at Software Placements for expert career advice, coding prep resources, and access to exclusive job opportunities in Ireland’s tech sector.