Building Products That Scale
Why products that work for 100 users often break at 10,000, and what to do about it.
TL;DR
- Scalability isn't just technical—it's about product decisions and user behavior
- Build for your next order of magnitude, not your dream scale
- Manual processes that work today become bottlenecks tomorrow
- User patterns change dramatically as you grow, requiring different solutions
- Early architecture choices have compounding effects on later scaling
Everyone talks about building scalable products. Few people actually do it. The gap isn't usually technical skill—it's knowing which battles to fight when.
Here's the trap: you can't build for infinite scale from day one. You'll over-engineer everything, move too slowly, and probably build the wrong thing anyway. But if you ignore scale entirely, you'll hit walls that require painful rewrites. The art is building for the scale you'll hit next, not the scale you dream about.
Most scaling problems aren't where people expect them. Everyone worries about database performance. Fair enough—that matters. But the real bottlenecks are usually in product decisions that seemed fine at the time. That manual approval step that takes five seconds? Works great when you have ten requests per day. At a thousand requests per day, it's a full-time job. At ten thousand, it's impossible.
User behavior changes as you scale, and your product needs to change with it. With a hundred users, everyone knows each other and self-regulates. With ten thousand users, you need moderation tools and clear policies. With a million users, you need automated detection and sophisticated abuse prevention. Same product, completely different requirements.
The features that got you to your current size often become the problems that prevent you from reaching the next size. That flexible customization option that delighted your first customers becomes a maintenance nightmare when you have ten different configurations to support. That personal touch where you onboard every customer yourself stops working when you're adding fifty customers per week.
Early technical decisions compound over time. Choose a database that can't shard and you'll rewrite your entire data layer later. Build tight coupling between components and every change becomes risky. Skip observability early and you'll be flying blind when things start breaking. These choices feel abstract when you're small, but they determine how painful scaling becomes.
Here's what actually works: build clean interfaces between components even if you're running everything on one server. You might not need microservices today, but if your code is modular, splitting it later is straightforward. Invest in monitoring before you need it. You can't debug what you can't see, and by the time you need visibility, it's too late. Make data archiving and cleanup part of your design from the start. Data only grows, and deleting things later is always harder than keeping them manageable from the beginning.
Think about your next order of magnitude. If you have a hundred users today, design for a thousand. If you have a thousand, design for ten thousand. Don't worry about a million until you're at a hundred thousand. This keeps you honest about real near-term needs without drowning in hypothetical problems.
Watch for manual processes disguised as features. Anything that requires human intervention to complete will eventually become a bottleneck. Either automate it or design it so it's optional. That review step might feel like quality control, but at scale it becomes the thing preventing you from moving fast.
Pay attention to quadratic problems. Things that scale with the number of users times the number of items, or the number of connections between users, or any other multiplicative relationship. These look fine when numbers are small and become disasters when they grow. A hundred users with a hundred items each is ten thousand operations. Ten thousand users with ten thousand items each is a hundred million operations. Spot these patterns early.
The hardest part of building scalable products isn't the technical implementation. It's having the discipline to do the right things before you have proof you need them, while also having the pragmatism to skip things you don't need yet. It's making architecture decisions that don't pay off for months while shipping features that matter today.
Most products don't fail because they couldn't scale technically. They fail because they scaled their problems faster than they scaled their solutions. The key is recognizing which problems are about to become critical and addressing them one step ahead, not ten steps ahead.
Build for where you're going next, not where you hope to be someday. Make it work for your current scale. Make it easy to change for your next scale. That's the whole game.