The transition from software engineer to software consultant is far more than a job title change, it's a fundamental shift in mindset that many technically skilled professionals struggle to make. While engineering excellence is necessary, it's rarely sufficient for consulting success. At Test Double, we've observed that the engineers who thrive in consulting roles share a distinct approach that sets them apart from day one.
When candidates interview with Test Double, or when consultants join a new client project, their approach to unfamiliar code reveals much about their readiness for consulting work. The difference between experienced consultants and those who struggle often comes down to one critical skill: how they engage with a new codebase for the first time.
Less experienced engineers typically jump straight into problem-solving mode. Given a task, they immediately search for places to apply solutions that worked for them in the past. While understandable (of course everyone wants to demonstrate value quickly) this approach often misses crucial context.
In contrast, experienced consultants start by taking inventory. They explore the codebase, investigate the decisions that created its current state, and understand the constraints and business needs at play. This intentional investment will pay dividends throughout the entire project.
Respecting the legacy in legacy code
One telltale sign of a consultant’s maturity is their attitude toward existing code. It’s easy (and common) for engineers to criticize unfamiliar code: “This is terrible”, “I can’t believe they did it this way”, or “If we could just switch to framework x or library y.” These knee-jerk reactions miss an important truth: that “imperfect” code has proven itself in a legacy of successfully powering a business and delivering value to customers.
Seasoned consultants approach legacy code with a healthy respect. They understand that every codebase tells a story of business needs, technical constraints, and trade-offs made under pressure. Instead of criticism, they approach with curiosity: “What circumstances led to this design?” and “What business needs was this code satisfying?”
This respectful posture builds trust with client teams and leads to more effective collaboration. After all, many team members likely contributed to that legacy code, and they’re much more likely to partner with someone who seeks to understand their work rather than dismiss it.
Embracing constraints rather than fighting them
Another differentiator between those who succeed as consultants and those who struggle is their relationship with constraints. Less experienced engineers often push against limitations, attempting to remake systems in their preferred image. They see constraints as obstacles to be overcome.
Successful consultants, however, embrace constraints as the creative boundaries within which they must work. They recognize that in established codebases of meaningful size, sweeping changes are rarely practical or prudent. Instead they ask: “What’s the smallest change I can make to start adding value today?”
This mindset, meeting the client and codebase where they are, proves surprisingly liberating. By accepting the reality of technical debt, architectural decisions, and business priorities, consultants can focus their creativity on solutions that work within the existing ecosystem rather than requiring its overhaul.
A critical shift: from inward to outward focus
All of these patterns point to a fundamental transition in a technologist’s career: the shift from an inward focus to an outward one. (Some might call this being customer-obsessed, in a good way!)
Early in our careers as software engineers, we naturally concentrate on developing our skills, establishing ourselves, and maximizing our individual impact. This internal focus serves an important purpose during our professional development.
However, successful consulting requires an inversion of these priorities; turning our focus outward to be laser-focused on prioritizing client needs over personal preferences. This client-centered approach means respecting legacy code, embracing constraints, and finding ways to add value within existing systems rather than reinventing them.
Practical tips for success: from interview to client engagement
Whether you’re interviewing with Test Double or looking to level up as a consultant, I wanted to share some practical ways to cultivate and demonstrate the consultant mindset and shift from inward to outward focus:
When approaching unfamiliar code
Map before you mine: Invest some initial discovery time creating a high-level map of the codebase before diving into specific features. Identify key modules, data flows, architectural patterns, and dependency relationships. Start with dependency manifests; they're a goldmine of information in a small package. I create these maps visually in Figma, drawing simple boxes and arrows to show how system components interact. Or keep a structured journal as you explore, noting file organization, naming conventions, and architectural boundaries. Pay close attention to integration points between systems and third-party dependencies; they often reveal the most critical design decisions. Use this map to explain the system to others and justify your proposed changes more effectively. Top consultants can see both the forest and the trees, clearly showing how individual components serve the larger system purpose.
Look for patterns, not problems: Seasoned software consultants spot patterns quickly within codebases. Develop the skill to suspend judgment based on your past experiences with other systems. Don't immediately compare what you see to your ideal architecture or previous projects—instead, focus on understanding the patterns unique to this specific codebase. Ask: What naming conventions do they use? How do they manage application state? How do their components communicate? Find the "cow paths", those well-worn routes that developers have created through repeated use which reveal the team's established workflows and habits. These patterns reveal the team's decisions, priorities, and values; like archaeological evidence of how they work. When you understand these patterns, you can propose changes that align with the team's existing mental models instead of forcing them to adopt completely new paradigms.
Pop the why stack: When you spot code that seems unusual or counterintuitive, don't label it as "wrong" or "problematic." Instead, build a mental "why stack" by asking, "Why might they have done it this way?" As you uncover answers through code analysis or conversations, dig deeper with follow-up "whys." This approach, similar to the "Five Whys" technique from root cause analysis, often uncovers hidden business requirements, historical constraints, or specific optimizations that explain those odd implementation choices. Embrace curiosity early; it's a consultant superpower with a limited shelf life. Once you've joined a team for a while, you'll lose the fresh perspective that makes these questions possible. Document what you learn, capturing the unwritten rules and constraints that will guide your future recommendations. The answer patterns you collect will build your credibility when you later propose improvements.
When encountering constraints
Identify the non-negotiables early: distinguish between true constraints versus preferences. True constraints include things like the established tech stack, deployment environments, regulatory requirements, and hard business deadlines; elements that cannot reasonably be changed during your engagement. Preferences, by contrast, are organizational habits that have calcified over time but could evolve with proper advocacy. Knowing this difference matters a lot; too many consultants burn time and goodwill trying to change things that won't budge, while missing the places where they could actually make a difference. When you understand which walls can't be moved, you can focus your creativity on designing within the available space rather than trying to reimagine the entire building.
Create constraint-specific spikes: build small prototypes that demonstrate feasibility. These "spikes" serve multiple purposes: they validate your understanding of the constraints, reveal hidden challenges, and build client confidence in your approach. The most effective spikes target the riskiest assumption about what's possible within the constraints. For example, rather than building an entire module, focus on the specific integration point you're concerned about. Present these spikes as learning exercises: "We built this small prototype to understand how the legacy authentication system would interact with the new feature. Here's what we discovered..." This approach transforms constraints from abstract limitations into concrete parameters for creative problem-solving.
Find the “just enough” solution: Resist the engineer's natural tendency to build comprehensive, future-proof solutions. Instead, develop a disciplined focus on meeting current needs effectively within existing constraints. Practice applying the YAGNI principle ("You Aren't Gonna Need It") by questioning each feature or optimization: "Is this necessary to solve the immediate problem?" When suggesting improvements, start with the minimum viable change that delivers value, then iterate based on feedback. This approach isn't about lowering standards, it's about recognizing that the most elegant solution might be the simplest one that works within the existing ecosystem. Learn to take pride in solutions that fit seamlessly into the constraints rather than stand out for their technical brilliance. A hallmark of consultant maturity is finding satisfaction in delivering pragmatic value rather than architectural perfection.
To shift from inward to outward focus
Shadow, shadow, shadow: spend time early in your engagement observing how people actually use the software you're working on. Partner with frontline customer support personnel; they possess a treasure trove of user pain points and workarounds that formal requirements often miss. Take note of the language users employ to describe problems, as this vocabulary becomes invaluable when you later advocate for changes. One hour of shadowing can provide more actionable insights than days of reading documentation, revealing the crucial gap between how software was designed to work and how it's actually used in practice.
The babel fish reference comes from Douglas Adams' "The Hitchhiker's Guide to the Galaxy," where this fictional creature serves as a universal translator when placed in one's ear. Like the babel fish, great consultants bridge communication gaps between different "species" of professionals.
Be the babel fish: spend time seeking to understand the business context, their customers, and their processes; in doing so, you will be uniquely positioned to help translate between technical and non-technical stakeholders. Doing this well can lead to faster agreement about the next most valuable step to take to make a change and it builds trust in both directions. Great consultants don’t just code; they connect worlds that often struggle to communicate effectively.
Come up for air and land the plane: develop a consistent practice of checking whether your explanations and recommendations are landing effectively. This means actively creating pauses in your communication to gauge understanding; what I like to call "coming up for air" or "landing the plane" by concluding conversations with clear action items. Watch for non-verbal cues of confusion, and practice asking, "Does this make sense given our constraints?" Remember that effective consulting is a dialogue, not a monologue – your goal isn't to showcase expertise but to ensure others can make informed decisions.
Consultant’s mindset in practice
At Test Double, our interview process intentionally evaluates candidates' ability to navigate unfamiliar code with respect and pragmatism. This isn't just an academic exercise, we've found that it directly predicts success in client engagements.
The consultants who thrive are those who approach each new project with humility and curiosity. They invest time in understanding before acting. They tip their hat to the existing work while rolling up their sleeves to make it better. And perhaps most importantly, they keep their focus squarely on delivering value to the client rather than showcasing their own technical prowess or leaning on past solutions. This distinction is crucial. As technologists, we often develop strong preferences for certain technologies, architectures, or approaches that have served us well in the past. There's a natural tendency to want to implement these familiar solutions regardless of context.
But exceptional consultants recognize that their personal technical preferences must take a backseat to client delight. They measure success not by how elegantly they've applied their favorite pattern or how purely they've implemented a technical solution, but by how effectively they've solved the client's actual problem within the existing ecosystem. This shift, from 'How can I demonstrate my expertise?' to 'How can I best solve this specific problem in this specific context?', represents the essence of client-centered consulting. It's often more challenging than it sounds, requiring both technical flexibility and humility, but it's what separates those who merely write code from those who create lasting value.
Adopting this mindset is a journey worth taking, regardless of your current role or career aspirations. If you're interested in developing this consultant mindset, whether you're considering joining Test Double or simply wanting to level up your effectiveness at your current organization, start by applying just one of these principles.
This mindset isn't just for consultants, it's for anyone who wants to create lasting value through their technical work.
