StringKick isn’t your typical online music blog. Started by a Dutch conservatory-trained musician and self-taught developer Just Rijna, the guitar education platform has spent the past ten years teaching what most tutorials overlook: real musicality and playing by ear.
What began as a handful of articles on musicality and relative pitch has grown into a full library of guitar courses, delivered through LearnDash and a WooCommerce-powered membership, and, most recently, StringKick Games: interactive learning games that hear your real guitar through the mic, a “Duolingo for guitar” as Just puts it.
We sat down with Just to talk about why he moved his platform to Servebolt, what changed once he did, and how something as fundamental as time to first byte ended up mattering more to his business than almost anything else he had tried.
The Opportunity: Bringing “Relative Pitch” to the Masses
StringKick didn’t start as a massive corporate venture; it started as a passion project born out of a stark realization. After graduating from music school, founder Just Rijna noticed that online guitar resources leaned heavily on rigid technical drills, while often overlooking the expressive core of music: musicality and the ability to play by ear.
Just knew that relative pitch, the skill that lets you play by ear, the way greats from Jimi Hendrix to John Mayer always have, isn’t a rare genetic gift; it’s a highly trainable skill. So he did what any curious person with an idea and a laptop does: he built a website. “How hard can it be?” he thought. He began tinkering with WordPress, writing articles, and then adding his first courses. That’s how StringKick started. Not with a business plan or a funding round, but with a musician who had firsthand experience to share, a WordPress install, and a willingness to tinker.
The coding skills came after. Just taught himself CSS and JavaScript, then more. Over the years, he grew genuinely passionate about web development, building out courses on LearnDash, adding WooCommerce to sell individual courses, then bundling everything into a membership with WooCommerce Subscriptions when the library grew large enough. The turning point was Make Your Ears Awesome, a series of ear-training courses that teach guitarists to work out songs by ear, riffs, melodies, and chord progressions, using real music, instant feedback, and a path that builds step by step from beginner to advanced. It was the first interactive course Just coded, and one that really resonated with students. The ear training articles had turned into something you actively do.
As the platform evolved, Just shifted from writing articles to engineering complex, immersive web software. His crown jewel, StringKick Games, acts as a “Duolingo for guitar”, and one thing sets it apart: it listens. Plug in or play acoustically, and the games hear your actual guitar through the mic. Away from your instrument, you tap the screen instead, so practice fits a couch, a commute, or a spare five minutes. The games are built on a principle Just calls the 90-10 rule: spend 10% of your time taking in new information and 90% actually practicing it. That’s where many guitar players get stuck: trapped in watching long YouTube explainer videos, without ever building the practical skills.
Running on a modern browser-based JavaScript framework, the games interface directly with the WordPress backend. Every time a student nails a level, unlocks an achievement, or saves game states, the platform triggers an intricate series of asynchronous database writes. To deliver an engaging experience, the infrastructure underneath had to be completely transparent, lightweight, and instantaneous.
The Challenge: Hitting the Infrastructure Wall
Before migrating to Servebolt, StringKick cycled through three different hosting providers. The last one was Kinsta, which is a premium managed WordPress provider. Just spent countless hours hyper-optimizing his code, tracking down rogue scripts, and shrinking image sizes down to the single-digit kilobytes to pass Google’s Core Web Vitals checks.
Despite his meticulous development work, the platform’s backend environment could not keep up. On his final day testing with Kinsta (July 15, 2021), Google PageSpeed Insights returned diagnostic alerts for the core lesson page (/blog-lessons/strumming-patterns/):
- The Core Blocker: Under field and origin data, the site explicitly failed the Core Web Vitals assessment across both mobile and desktop ecosystems over the trailing 28-day period.
- The Latency Diagnostic: PageSpeed Insights flagged a critical performance bottleneck: “Reduce initial server response time,” exposing a structural 0.66-second (660ms) server processing lag native to the host’s server architecture.
“After spending dozens of hours writing an article or building an interactive course, the last thing you want is for server response time to be the reason people leave before they’ve seen any of it.”
Just Rijna, Founder
There was a business reason behind the urgency, too. A large share of StringKick’s traffic comes from organic search, and Just knew speed was a ranking factor. “You’d hate to do all that SEO and marketing work, only for site speed to be the reason you don’t rank as high as you could,” he explained. More traffic meant more students, and a slow site put a ceiling on both.
Just was caught in an industry-wide trap: running a dynamic, heavy application on infrastructure built only for static content presentation, while facing the usual hosting upsells to handle standard database interactions.
Why StringKick Chose Servebolt: Speed, Sustainability, and True Musicality
At that point, it was time to find a new stable home for his growing online business. Just doesn’t romanticize the search process. He ran his own tests: grabbed a copy of the site, spun it up on different hosts, and measured. No marketing decks. Just raw numbers.
The comparison wasn’t close. Switching to Servebolt brought his time to first byte down immediately, with no further optimization required on his end. Servebolt and his previous host cost roughly the same amount, which helped seal the decision.
“Switching web hosts alone brought it down that much—that’s incredible. All those recommendations about making images 10 KB smaller? Sure, they help. But if time to first byte is too high, that’s a blocker no matter what else you do.”
Just Rijna, FounderCore Benchmark Comparison
Environment & Metric Layer Baseline (Kinsta — July 15, 2021) Post-Migration (Servebolt — Aug 13, 2021) Real-World Performance Impact Mobile Field Data (Real Users) FAILED Core Web Vitals Transitioning (FCP shifted down to 2.3s) Accelerated first paint for mobile visitors Desktop Field Data (Real Users) FAILED Core Web Vitals PASSED Core Web Vitals Direct ranking & UX validation from Google Desktop Real-User FCP 2.6 seconds 1.9 seconds 27% faster content delivery to actual visitors Desktop Real-User LCP 3.0 seconds 2.5 seconds 16.6% reduction in main visual load times Mobile Speed Index (Lab) 4.0 seconds 2.8 seconds 30% improvement in overall visual rendering Critical Server Bottleneck 0.66s (660ms) TTFB Lag 0.00s (Completely Eliminated) Server latency removed from the critical path
Beyond the metrics, there was a deeper fit in two areas:
Environmental Harmony
As an educational platform processing high volumes of persistent requests, StringKick’s server footprint matters. Just prioritized hosting infrastructure that values sustainability. Servebolt’s green data centers and optimized architecture require less power to handle large database workloads compared to conventional hosting setups. By improving performance at the system level, Servebolt reduces both environmental impact and page latency.
Digital “Musicality”
That alignment extends to Servebolt’s core value of Musicality, which in music refers to how individual parts form a coherent performance when played together. Built from the bare metal up, Servebolt’s architecture applies this idea across the entire stack, with the operating system, PHP execution, and database layer moving in precise coordination.
How Servebolt Responded: Infrastructure Powered by Real People
Migrating an educational application with active student subscriptions, progress-tracking systems, and complex API endpoints carries significant risk. Servebolt handled the transition and completed it without operational downtime or data loss.
Flexibility in Billing and Currency
Prior to moving to Servebolt, Just encountered an administrative bottleneck common to international creators: although his company operated in Europe, his student revenue arrived in US Dollars (USD). He asked whether his hosting invoices could be issued in USD to better align costs with revenue and reduce exposure to foreign exchange fluctuations and conversion fees. In many environments, billing systems are not configured for this level of flexibility, but Servebolt reviewed the request and adjusted the billing setup to support USD invoicing.
Human Engineering Over Chatbots
While some web hosting providers have shifted toward replacing traditional support roles with AI-driven triage systems or heavily automated first-line support in an effort to reduce costs, Servebolt has intentionally maintained a human engineering support model. Whenever Just faced complex setup questions during his early configurations, he interacted directly with senior technical leads who resolved issues while explaining the underlying system mechanics.
“Every time I contact support, I am dealing with an actual human expert who understands exactly what I am trying to build. Over the last two years, my support requests have dropped to practically zero – not because help isn’t there, but because the platform works so flawlessly that I never need to reach out.”
Just Rijna, Founder
Tangible Results & Real ROI
Before moving to Servebolt, hosting was a stress-inducing point of failure. Following the migration, and now half a decade in, StringKick has run without operational issues, and hosting has become an invisible asset.
The Immediate 2021 Impact
Only 28 days after switching to Servebolt, Just’s own PageSpeed Insights checks showed a clear and dramatic improvement:
- Core Web Vitals Cleared: The historical 0.66s server lag warning was entirely eliminated.
- The Passing Grade: On desktop metrics, the platform shifted to a “passes the Core Web Vitals assessment” status, with a stable 98 overall score, establishing a strong foundation for search engine optimization and user acquisition.
The Next-Gen Linux 8 Evolution
When Servebolt launched its custom Linux 8 platform to boost processing speed, StringKick was moved over with no extra work needed from Just. The real-world results matched Servebolt’s own benchmarks:
| Platform Version | Benchmark Time to First Byte (TTFB) | Performance Delta |
| Servebolt Linux 7 | 613 ms | Baseline |
| Servebolt Linux 8 | 294 ms | 52.03% Reduction in Latency |
Purely through structural operating system optimizations, StringKick’s initial response time was reduced by half. The improvement aligned with Servebolt’s broader Linux 8 rollout, where uncached performance gains ranged from 30% to over 500% depending on the original setup.
Scalability for StringKick Games
Since StringKick Games runs interactive browser levels one after another, the platform needs to handle many concurrent connections. Here’s how Servebolt supports this setup:
- Handling Traffic Surges: When Just shared the game on platforms like Reddit, traffic doubled. The architecture maintained stable response times for all global users.
- Complete Creative Freedom: With hosting concerns removed, Just can now focus on building, creating content, and supporting his community.
The Invisible Infrastructure
Here’s something Just said during our conversation that stuck: “When you finish building a feature, you don’t want to be slowed down by the annoying technical thing like hosting. You just want it to work.”
That’s not a small thing for a solo founder running a WordPress-based platform with gamified interactive experiences, a membership subscription layer, and real-time database calls firing every time someone completes a lesson. Each of those user interactions is a request. Each slow response is a moment where the product feels less polished than it actually is.
“Speed is such a simple part of product feel. But if something feels laggy or isn’t loading properly, it makes the whole thing feel not so well-crafted even if everything else is great.”
Just Rijna, Founder
A Partnership Built to Last
In a landscape increasingly shaped by AI-driven interaction layers, both StringKick and Servebolt have built their reputations on direct human ownership of their respective domains. Just maintains a direct relationship with his students by sending personal emails when new students sign up, while Servebolt maintains direct technical ownership of its infrastructure through custom software optimization, efficient infrastructure design, and access to experienced technical teams.
By removing server bottlenecks that hold online platforms back, Servebolt gave StringKick the performance boost it needed to grow from a regular educational site into a strong, game-like learning platform.
“If a fellow creator asks me for a recommendation to secure proper hosting, my answer is always Servebolt. It is incredibly fast, the support team is genuinely knowledgeable, and their commitment to sustainability is completely aligned with how I run my business. Staying with a single host for five years speaks for itself.”
Just Rijna, Founder
What’s Next for StringKick
Now, most of Just’s time goes into the games. What began with a single note-naming game has grown into full learning paths: string names, note names, intervals, and chord theory are live, with more on the way, such as triads, scales, chord progressions, and deeper ear-training work, all wrapped in the same game-like format.
The next chapter is already running on Just’s phone: a native StringKick Games app, currently in testing. It’s built to provide a more polished, more immediate experience on your phone that makes it even easier to build your skills wherever you are, guitar in hand or not. And it runs on the same foundation as everything else: the app talks to the same WordPress backend on Servebolt as the website, so everything syncs to one account. Finish a level on the couch, and it’s waiting at your desk.
“Duolingo for guitar” began as Just’s shorthand to explain what he was building. These days it’s how new students find StringKick. The plan from here is simple: wherever you are, whatever spare minutes you have, the next level is waiting.
