Tech Fluency > Tool Fluency: What Actually Makes You a Strong Engineer
✨ Dev Shorts #4 - short and meaningful.
Hey,
Hope you are doing well!
I’m back with a new topic from the ✨ Dev Shorts collection (a little bit longer this time 🙈). We’re going to talk about tools and technologies and what could make you a strong engineer.
I’ve recently joined a new team, and as I started exploring their tech stack and tools during onboarding, I found myself asking:
What actually makes a frontend engineer stand out?
That question led me here, writing this piece.
I hope you’ll enjoy it—and as always, I’d love to hear your thoughts or feedback.
Over the years, I’ve worked with React, Vue, Next.js, Vite, Rsbuild, Zustand, Redux, Tailwind, SCSS, Jest, Vitest—you name it.
And yet, whether I was building a new feature or debugging a production issue, none of those tools mattered more than how I thought through the problem.
In today’s frontend world, tool fluency is the trend—but it’s tech fluency that actually scales your impact.
That’s a lesson I’ve learned many times throughout my career.
But it hit differently last year, when I was part of a team responsible for supporting live production deployments and dealing with critical bugs—often under pressure, with limited context, and no time to go down a stack rabbit hole.
Tech fluency in action
In one case, QA reported a bug that occurred only when a specific combination of user permissions and feature flags was active. The feature in question was live for internal users but hidden for external customers, and the logic around rendering had evolved over several iterations.
There was no stack trace, no visible error in the browser, and no time to schedule a deep dive.
I hadn’t worked on that exact part of the code before, but instead of jumping into every helper function or toggling flags blindly, I did what I knew best: I traced the logic like a flow diagram.
What data was being passed down to the component?
Which layer handled conditional rendering?
Was the feature flag being checked too late—or not at all?
Step by step, I walked through how the permissions were initialized, how the flags were evaluated, and how the UI responded—or didn’t.
What stood out was this: the feature flag system was asynchronous—flags were fetched only after the user logged in and their identity and roles were confirmed. However, one component down the tree was assuming that the flags were already available at render time. It accessed the flag directly and used it in a conditional without guarding against the case where the value was still undefined.
That led to an edge case where, during the initial render after login, the component would skip rendering a key UI element—or worse, throw an error—because the flag it relied on hadn’t been loaded yet. In local and dev environment (where everything loaded fast), this bug rarely appeared. But in production, with feature flags dependent on real user roles and network latency, it broke silently.
Eventually, I realized that the solution wasn’t about fixing the flag value—it was about fixing the assumption. The component needed to treat the flag state as pending / loading, and either wait for it to resolve or render a fallback UI while loading.
The fix was small. But the ability to find it—that came from tech fluency.
Not from knowing the exact implementation of the flagging system or how the internal UI library worked, but from understanding how to reason through a problem in a large system.
Tool fluency helps you when the path is clear.
Tech fluency helps you when it’s not.
Tool Fluency vs Tech Fluency
Let’s break it down.
Tool fluency is about knowing the syntax, APIs, and best practices of the frameworks, libraries, and tooling you use.
It’s what lets you spin up a Next.js app quickly, set up a test in Vitest, or configure Tailwind without looking at the docs.
It’s valuable.
It makes you efficient—in known environments.
But tech fluency is deeper. It’s about:
Understanding how data flows through an application
Knowing how rendering decisions are made
Recognizing performance bottlenecks
Debugging without relying on error messages
Navigating unfamiliar systems with confidence
Tech fluency is what helps you onboard faster, ask better questions, and solve tougher problems—even when the stack is new, undocumented, or messy.
Why it matters
Tools evolve over time. Libraries come and go.
What made you productive in 2021 might be irrelevant in 2025.
But tech fluency? That stays with you. It will build up.
It’s what turns a good engineer into a reliable teammate, a strong code reviewer, a resilient problem solver.
So by all means, learn the tools—they’re your leverage.
But build your foundation on understanding, not just usage.
Until next time 👋,
Stefania
If this sparked something for you, I’d love to hear it.
📨 Feel free to share how tech fluency has helped you navigate a messy bug or a new stack—I’d be happy to include your examples in a follow-up piece.
Articles from the ♻️ Knowledge seeks community 🫶 collection: https://stefsdevnotes.substack.com/t/knowledgeseekscommunity
Articles from the ✨ Frontend Shorts collection:
https://stefsdevnotes.substack.com/t/frontendshorts
👋 Get in touch
Feel free to reach out to me here on Substack or on LinkedIn.