When to Build Custom Software vs Use Off-the-Shelf Tools
Not sure whether to build custom software or buy off-the-shelf? Learn the real signals that tell you when SaaS tools stop being an asset and start costing you more.
We architect, rescue, optimise, and scale Ruby on Rails applications, with 45+ engineers and 10+ senior architects who have built, broken, and fixed more Rails systems than most teams will ever see.
Rails applications have a predictable lifecycle. They start fast, conventions accelerate development, the codebase is clean. Then, somewhere between Series A and serious scale, something shifts. Queries that ran in 20ms now take 800ms. Background jobs back up. Every new feature takes twice as long as it should.
This is not a Rails problem. It’s an architecture and ownership problem, and it’s exactly what we exist to solve.
NUS Technology is a dedicated Ruby on Rails engineering team based in Ho Chi Minh City, Vietnam. With 45+ engineers and 10+ senior architects, our sole focus is Rails: building new platforms, optimizing existing ones, rescuing projects that went wrong, and upgrading applications the business has outgrown. We serve SaaS companies and engineering leaders across the US, Australia, and Europe who need full ownership, not a vendor that disappears after delivery.
We are proficient across many technologies, but our core expertise is in Ruby on Rails. We champion this framework for a strategic reason: it allows us to build robust, scalable, and maintainable applications with a philosophy that prioritizes your speed-to-market, code quality, and long-term business value.
Launch faster. Rails' conventions and powerful libraries cut setup time, so we focus on features that matter—getting your MVP to market and revenue sooner.
Trusted by giants like Shopify and GitHub, Rails is a battle-tested framework. Its mature ecosystem provides a secure, stable foundation for your product.
Rails' clean code reduces long-term ownership costs. Its structure makes the application easier to maintain and extend, ensuring it remains agile.
Rails scales with ambition. From startups to global platforms, it powers millions of users and transactions when built with the right expertise.
Your Rails application handled 100 concurrent users without a problem. At 1,000, something changed. Response times are climbing, background jobs are backing up, and your team has spent three sprints trying to fix it without a clear diagnosis.
The codebase has grown over three or four years and now nobody on the team fully understands it. Every change risks breaking something else. New engineers take months to get productive.
You have a Rails platform to build or rebuild, and you cannot afford to get the architecture wrong again.
Your internal Rails team is good but not deep enough to accelerate the roadmap. You need senior engineers who slot in, not contractors who need managing.
When your Rails app has slow tests, fragile deployments, and features taking three sprints to ship, the problem is architectural. We inherit troubled applications, stabilize what’s broken, and build a modernization roadmap. We’ve rescued vendor-abandoned apps, upgraded across major Rails versions, and turned velocity-killing codebases into systems teams are proud of.
Rails performance problems share the same root causes: N+1 queries, unindexed tables, untuned background jobs, and missing caching. We profile under real load, identify the specific queries and processes causing degradation, and implement targeted fixes that typically reduce response times by 60 to 80%. We measure, fix, and measure again.
Most Rails apps are built to launch. Ours are built to compound, meaning the codebase gets easier to work with as it grows. Before writing a line of code, our architects design the full system: data model, service layer, API boundaries, deployment strategy. Two weeks of upfront design saves six months in year one.
Built for engineering leaders who need senior Rails capability that slots into existing workflows, sprints, and standards. Every dedicated engineer is a full-time employee supervised by a principal architect, no rotated contractors. The engineer who learns your codebase on day one is still there on day 180.
We read and document the existing codebase. We map the data model, identify the architectural decisions (and their consequences), run automated coverage analysis, and produce an honest assessment of what is sound and what is not.
We produce a prioritized remediation plan. We separate what needs to change now (security, data integrity, critical performance) from what can wait (code quality, test coverage, architectural improvements).
We begin executing the plan in phases, maintaining feature development alongside remediation so the business does not stop while the codebase heals.
We will never tell you the previous work was good when it was not. We will never overstate the problem to justify a full rewrite when a targeted refactor will do.
Our team isn't just a collection of developers; it's a center of excellence. With 45+ engineers, including a core of 10+ senior and principal architects, we have the collective experience to solve any challenge. Your project is always overseen by our most senior talent.
We are fanatical about clean code, solid architecture, and best practices. We build applications that are not just functional but also a pleasure to maintain and extend, saving you time and money over the long term.
We have successfully launched and scaled numerous complex Rails applications for clients across the globe in SaaS, E-commerce, and EdTech. Our portfolio of successful, high-traffic applications is the ultimate proof of our expertise.
Ruby on Rails (all versions), Hanami, Sinatra
RSpec, Minitest, Capybara, FactoryBot
PostgreSQL, MySQL, Redis
Sidekiq, Resque
Docker, Kubernetes, Heroku, AWS, CI/CD
Hotwire (Turbo, Stimulus), React, Vue.js
When BestEx Research engaged NUS Technology, the ask was not to build something new. It was harder than that: take over a live, production codebase and keep it running while continuing to grow it.
When Twinlite, a prominent property management company, sought to enhance their existing VestaLiving platform, they partnered with NUS Technology.
Founded by Alissa (Williams) Wilkinson, an expert in the health and fitness domain, Pursuit Lab was born from avision for a unified platform to revolutionize how clinics manage their clients and how clients experience their fitness journey.
Explore our latest insights on strategy, engineering, and the art of building exceptional software that drives real business results.
Not sure whether to build custom software or buy off-the-shelf? Learn the real signals that tell you when SaaS tools stop being an asset and start costing you more.
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Let’s talk about your project and see how our Ruby on Rails team can help you build it right.
