Engineering • Leadership

Red Flags When Hiring Your First Software Engineer

Your first engineering hire will shape your product for years. Most non-technical founders focus on technical skills they cannot evaluate and miss the warning signs they absolutely can spot. Here is what to watch for at every stage of the process.

Mike Tempest • 10 min read • 27 March 2026

Hiring your first software engineer is one of the highest-stakes decisions a funded startup makes. This person will not just write code. They will make architectural decisions that you will live with for years. They will set the engineering culture. They will be the person future hires measure themselves against. Get it right and you build momentum. Get it wrong and you lose six months of runway, plus the time it takes to undo their decisions.

The problem for non-technical founders is that most hiring advice focuses on evaluating technical ability, the one thing you genuinely cannot assess yourself. That matters, and you should bring in outside technical help for that part. But technical skill is only half the picture. Many of the most damaging red flags are entirely visible to non-technical founders, if you know what to look for.

This guide covers the warning signs at every stage: the CV, the interview, reference checks, and the trial project. These are patterns I have seen repeatedly across dozens of startups. They are not theoretical. Every red flag here has cost a real company real money.

Why Your First Engineer Hire Is Different

Before we get into specific red flags, it helps to understand why this particular hire carries so much weight. This is not like hiring a marketing manager or a sales lead. The asymmetry of outcomes is far greater.

They set the technical foundations

Your first engineer chooses the programming languages, the frameworks, the database, the hosting infrastructure, and the overall architecture. These decisions are expensive to reverse. A bad choice does not always show up immediately. It shows up eighteen months later when you are trying to scale and the foundations cannot support it. By then, you are looking at a partial or full rebuild.

They define the engineering culture

The first engineer's working habits become the default. If they write tests, future hires will write tests. If they document their code, the codebase stays maintainable. If they cut corners, corner-cutting becomes the norm. Culture is set by the earliest hires, and it is extremely difficult to change once established. Your second and third engineers will mirror the standards of your first.

They become the benchmark

Every subsequent engineering hire will be evaluated relative to this person. If your first engineer is strong, they will attract and retain strong people. If they are weak, strong candidates will see it during the interview process and decline the offer. Good engineers want to work with other good engineers. A weak first hire creates a downward spiral that is painful to reverse when you start building your first engineering team.

You cannot easily evaluate their output

With a sales hire, you can see the pipeline. With a marketing hire, you can see the campaigns. With an engineer, the output is code you cannot read. This information asymmetry means problems can hide for months. The product might look like it is progressing while the underlying code is a mess. By the time the problems become visible to a non-technical founder, through slow delivery, frequent bugs, or difficulty hiring, the damage is done.

CV Red Flags: What to Spot Before the Interview

The CV screen is your first filter, and you do not need to be technical to use it well. These patterns consistently predict problems down the line.

Job hopping without progression

Multiple roles of six to twelve months is worth investigating. Sometimes there are legitimate reasons: contracts, redundancies, startup failures. But a pattern of short stints with no upward trajectory often signals someone who either gets bored quickly, creates conflict, or gets managed out before the probation period ends. For your first hire, you need someone who will stay long enough to see their decisions through. Ask directly about each short stint. The explanation matters more than the pattern itself.

Technology list without context

A CV that reads like a technology catalogue, listing twenty programming languages and thirty frameworks, without explaining what was built with them is a warning sign. Strong engineers describe what they built, the problems they solved, and the impact of their work. Weak engineers list technologies because they have nothing else to say. Look for descriptions of outcomes: "Reduced page load time by 60%", "Built the payment system that processed £2M monthly", "Led migration from monolith to microservices serving 50k daily users." If every bullet point is a technology name, the candidate is padding.

No evidence of owning anything end-to-end

Your first engineer needs to be someone who can take a feature from idea to production independently. Look for evidence of ownership: "I built", "I designed", "I led". If every description uses passive language or team-level attribution, "Worked on the billing system", "Part of the team that delivered the mobile app", the candidate may have only ever operated as a cog in a larger machine. That is fine for hire number five. It is dangerous for hire number one, where there is no machine to be a cog in.

Only large company experience

Someone who has spent their entire career at large corporations, banks, consultancies, or enterprise software companies, may struggle in a startup environment. Large companies have established processes, dedicated teams for infrastructure, security, and operations, and clearly defined roles. At a startup, your first engineer needs to do all of it: write the code, set up the hosting, configure the CI/CD pipeline, handle the deployments, and probably answer customer support tickets about technical issues. This is not a judgement of ability. It is a question of fit. Ask how they feel about ambiguity and wearing multiple hats.

Gaps that do not add up

Career gaps are not inherently red flags. People take time off for family, health, travel, or personal projects. The red flag is when gaps are hidden or the timeline does not add up. If the dates on a CV seem to overlap oddly or there are unexplained six-month periods, ask about them directly and kindly. A candidate who is transparent about a gap is far more trustworthy than one who tries to disguise it.

Interview Red Flags: What to Listen For

The interview is where most non-technical founders feel out of their depth. But the most important signals have nothing to do with code. These are the patterns that predict whether someone will thrive or create problems in your startup.

They cannot explain things simply

Ask them to explain a technical project they worked on as if you were a non-technical colleague. If they cannot do it, that is a problem. Your first engineer will need to communicate with you constantly: explaining trade-offs, justifying decisions, translating technical constraints into business terms. An engineer who hides behind jargon is either not as experienced as they claim, not a strong communicator, or not interested in collaborating with non-technical people. None of those are acceptable for this role.

They blame previous employers for everything

Ask why they left their last few roles. Everyone has had bad managers or frustrating environments. But if every previous company was terrible, every manager was incompetent, and every team was dysfunctional, the common denominator is the candidate. Listen for ownership. Strong candidates say things like "The role was not the right fit because I wanted more ownership" or "I learned a lot but the company's priorities shifted away from what I was hired to do." Weak candidates say "The management was clueless" and "The codebase was a disaster and nobody listened to me."

They are more excited about the technology than the problem

Ask what interests them about your company. If the answer is entirely about the technology stack, "I love working with React" or "I have been wanting to use Kubernetes in production", be cautious. You need someone who cares about solving your business problem. Technology-first engineers will push for over-engineered solutions, unnecessary rewrites, and shiny tools that add complexity without adding value. The best first hires get excited about the problem you are solving and see technology as the means, not the end. This is especially important at the startup stage where technology choices should serve the business, not the other way around.

They have no questions about the business

An engineer who does not ask about your customers, your revenue model, your competitive landscape, or your growth plans is telling you something. Either they are not curious, which is a problem in a startup where everyone needs to understand the business, or they do not care about context, which means they will build the wrong things. The strongest first-engineer candidates ask more business questions than technical ones. They want to understand the problem space because they know that understanding the problem is prerequisite to building the right solution.

They push back on process without offering alternatives

Some pushback is healthy. You want an engineer who will challenge bad ideas. But there is a difference between constructive disagreement and reflexive resistance. If a candidate dismisses every process, "I do not believe in code reviews", "Standups are a waste of time", "Documentation slows you down", without offering what they would do instead, you are looking at someone who will be difficult to manage. Your first engineer needs to be someone who can build process, not someone who tears it down.

They cannot describe a mistake they have made

Ask about a time they made a significant technical mistake and what they learned from it. Every experienced engineer has shipped bugs, made poor architecture decisions, or underestimated the complexity of a project. If a candidate cannot give a genuine example, they are either too junior to have encountered real problems, too proud to admit them, or not self-aware enough to recognise them. All three are disqualifying for a first hire where you need someone who learns quickly from inevitable mistakes.

Reference Check Red Flags: What People Will Not Say Directly

Reference checks are where most founders go wrong. They treat them as a formality. Done properly, references are one of the most valuable parts of the entire process. Here is how to read between the lines.

They can only provide references from years ago

If a candidate with ten years of experience can only offer references from their first or second job, something is wrong. Recent managers and colleagues should be willing to vouch for good engineers. If nobody from the last three to five years will speak on their behalf, ask yourself why. Sometimes there are reasonable explanations, such as a manager who left the industry or a company that no longer exists. But if the pattern persists across multiple recent roles, it is a significant warning sign.

Faint praise

References rarely say anything explicitly negative. Instead, they damn with faint praise. Listen for the difference between "She was one of the best engineers I have ever worked with" and "She was fine, she did her job." Pay attention to enthusiasm, specificity, and whether the reference would hire them again. The single most telling question is: "If you were starting a company tomorrow, would you hire this person?" A pause before answering tells you everything. A genuine yes is usually immediate and emphatic.

Inconsistencies with the candidate's story

Cross-reference what the candidate told you with what the references say. If the candidate described themselves as the technical lead on a project but the reference says they were one of four contributors, that is a problem. Minor differences in perspective are normal. Fundamental disagreements about the candidate's role, responsibilities, or achievements are not. Keep notes from your interviews and compare them directly with reference feedback.

They only offer personal references

Friends will always say nice things. What you need are professional references: former managers, colleagues who worked with them daily, or stakeholders they delivered work to. A candidate who can only provide friends or family as references either has no professional relationships worth offering or is specifically avoiding people who would give an honest assessment. Insist on at least one direct manager and one peer from their most recent role.

The reference focuses on personal qualities, not work

"Great person to have in the office" and "Really fun at team events" are not what you are looking for. You want to hear about their work: reliability, code quality, ability to work independently, communication with non-technical people, how they handled pressure. If a professional reference cannot speak to the quality of someone's work, they either did not work closely enough to know, or the work was not memorable enough to comment on. Ask specific questions about work output to steer the conversation.

Trial Project Red Flags: What the Work Reveals

A paid trial project is the closest thing to a crystal ball in hiring. It shows you how someone actually works, not how they interview. Always pay for trial work, both because it is the right thing to do and because it attracts better candidates. Here is what to watch for, even without reading the code yourself.

They do not ask clarifying questions

Give them a deliberately ambiguous brief. A strong engineer will come back with questions: "What should happen when X?", "Is Y in scope or out of scope?", "I noticed the brief does not mention Z, should I handle that?" An engineer who takes an ambiguous brief and disappears for a week without asking a single question is either building the wrong thing, making assumptions they should not be making, or not experienced enough to spot the ambiguity. All three are problems for a first hire where clear communication is essential.

They massively over-engineer the solution

If you asked for a simple feature and they deliver an enterprise-grade system with a microservices architecture, that is a red flag. Over-engineering is one of the most common and expensive habits in software development, and it is particularly damaging at the startup stage where speed matters more than scalability. Your first engineer needs to understand that the right solution is the simplest one that works and can be iterated on. An over-engineered trial project predicts an over-engineered codebase.

They miss the deadline without communicating

Deadlines slip. That is normal in software development. The red flag is not missing the deadline. It is missing the deadline without telling you beforehand. A strong engineer realises two days in that the work is bigger than expected and sends a message: "This is taking longer than I estimated. Here is why, and here is when I expect to finish." A weak engineer goes silent and delivers late, or delivers something incomplete without explanation. How someone handles a slipping timeline on a trial project is exactly how they will handle it on your product.

They cannot walk you through their decisions

After the trial project, ask them to walk you through what they built and why they made the decisions they did. This is where you learn the most, even without technical expertise. A strong engineer will explain their trade-offs: "I chose this approach because it is simpler to maintain, even though this other approach would be slightly faster." A weak engineer will either struggle to explain their reasoning or default to "this is just how you do it." You want someone who makes deliberate, reasoned decisions, not someone who follows patterns without understanding them.

The code works but there is no documentation

You may not be able to evaluate code quality directly, but you can check whether there is a README file that explains how to run the project, what decisions were made and why, and what you would need to know to extend it. An engineer who delivers working code with zero documentation is showing you how they will treat your codebase. In six months, when someone else needs to understand what was built, there will be nothing to guide them. Documentation is a signal of professionalism and consideration for the people who come after you.

How to Protect Yourself as a Non-Technical Founder

Spotting red flags is only half the battle. You also need structural protections that limit the damage if you get it wrong. Because sometimes you will. Even experienced technical leaders occasionally make bad hires.

Get independent technical assessment

Do not rely solely on your own judgement for the technical evaluation. Bring in a fractional CTO, a technical advisor, or a trusted senior engineer to assess the candidate's technical skills, review their trial project code, and sit in on a technical interview. This costs a few hundred pounds and can save you tens of thousands. Consider it insurance, not an expense.

Use a proper probation period

Set a clear three to six month probation period with defined milestones. Do not make it vague. Agree upfront on what success looks like at 30, 60, and 90 days. Check in against those milestones regularly. If things are not working at three months, they are unlikely to improve at six months. The probation period is only useful if you actually use it, and most founders do not. They hope things will get better. They rarely do.

Structure equity vesting with a cliff

If you are offering equity, use a standard four-year vesting schedule with a one-year cliff. This means the engineer receives no equity if they leave or are let go within the first year. Without a cliff, a bad hire who leaves after three months walks away with equity in your company. The cliff protects you and ensures the engineer is incentivised to stay and perform long enough to demonstrate real value.

Establish code review from day one

Even if you cannot review code yourself, establish the expectation that all code will be reviewed. Use your technical advisor or fractional CTO to conduct periodic code reviews, monthly at minimum. This serves two purposes: it catches problems early, and it sends a clear signal that code quality matters and will be monitored. An engineer who knows their work will be reviewed writes better code than one who knows it will not.

Ensure you own the code and access

This is non-negotiable. All code must be in a repository owned by the company, not the engineer's personal account. All hosting, domain, and third-party service accounts must be under company ownership with credentials stored in a shared password manager. If your first engineer leaves tomorrow, you should be able to continue operating without them. If they are the only person with access to production, you have handed them leverage you cannot afford to give.

The Bottom Line

Hiring your first engineer is not a decision you can afford to get wrong, and it is not one you need to make blind. The red flags covered here are visible to any founder who knows what to look for. You do not need to read code to assess whether someone communicates clearly, takes ownership, shows genuine interest in your business, and works professionally.

The founders who hire well share a common trait: they slow down. They resist the pressure to fill the role quickly. They invest time in proper CV screening, structured interviews, thorough reference checks, and paid trial projects. They bring in outside technical help for the parts they cannot assess themselves. And they build structural protections, probation periods, code reviews, proper access controls, that limit the damage when things go wrong.

The founders who hire badly also share a common trait: they rush. They take the first candidate who seems capable because the pressure to ship is overwhelming. They skip reference checks because the candidate interviewed well. They skip the trial project because they do not want to slow down the process. Six months later, they are back to square one, with less runway and more technical debt.

Take the time. Do the process. Your first engineering hire is a six-figure decision with multi-year consequences. Treat it accordingly.

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Frequently Asked Questions

How long should the hiring process take for a first engineer?

Expect four to six weeks from posting the role to a signed offer. Rushing this process is one of the most expensive mistakes founders make. A bad first hire can cost you six months of runway between salary, management time, and the cost of replacing them. Build in time for a proper CV screen, two interview rounds, reference checks, and a paid trial project.

Should I hire a senior or junior engineer as my first hire?

Almost always senior, meaning someone with at least five years of professional experience shipping production software. Your first engineer will make architectural decisions that shape your product for years. A junior engineer needs mentorship and code review that you cannot provide as a non-technical founder. The salary difference is significant, but the cost of getting the foundations wrong is far higher.

Can I assess engineering candidates without being technical?

You can assess a surprising amount. Communication skills, problem-solving approach, ownership mentality, and cultural fit are all visible without reading code. For technical assessment, bring in outside help: a <a href="/what-is-fractional-cto" class="text-accent-red underline">fractional CTO</a>, a technical advisor, or a trusted senior engineer. Never skip the technical assessment entirely just because you cannot conduct it yourself.

What should I pay my first software engineer in the UK?

For a senior full-stack engineer in the UK in 2026, expect to pay between £65,000 and £90,000 base salary outside London, or £80,000 to £110,000 in London. Add 10 to 20 percent for equity, benefits, and employer costs. If you are offering significantly below market rate, you will attract candidates who cannot get hired elsewhere, which is itself a red flag.

Should I use a recruitment agency for my first engineering hire?

It depends on your network and timeline. Agency fees typically run 15 to 25 percent of first-year salary, which is substantial at the seed stage. If you have access to a strong technical network through advisors, investors, or a fractional CTO, direct hiring is more cost-effective and often produces better candidates. If you have no technical network and need to move quickly, a specialist tech recruiter who understands startup hiring can be worth the fee.

Mike Tempest

Fractional CPTO

Mike works with funded startups as a Fractional CPTO, helping non-technical founders make better technology decisions. As Head of Engineering, he scaled RefME from 0 to 2M users, and as CTO turned Risika profitable in 18 months through business-first engineering.

Learn more about Mike