"Build a URL shortener" is one of the most common prompts in a developer interview. It's used precisely because it seems straightforward: accept a long URL, generate a short one, redirect traffic. Most engineers can sketch out the architecture in minutes.
And look, it's true: building a link shortener isn't that hard. With modern tooling and AI assistance, you can have a working link shortener up in less than a day. And if all you need to do is shorten a handful of links, it will probably be fine. But for companies needing hundreds, thousands, or millions of reliable, trackable, and secure links, you're asking for trouble.
Building a link shortener is easy; it's what happens afterwards that gets complicated.
The infrastructure costs nobody budgets for
Most teams budget for the build. Few budget for what comes after.
A link shortener needs a database to store link records. It needs a separate, differently structured database to store click data, because analytics data grows much faster than link data. One link can generate thousands of clicks, and that data needs to be queryable in ways that standard link storage isn't designed for. Add caching layers, load balancers, monitoring, and backups, and you're managing a non-trivial amount of infrastructure before you've built a single feature beyond basic redirection.
Running a reliable link infrastructure is expensive: storage, compute, data transfer, and redundancy. Building your own doesn't make those costs disappear. It just moves them from a predictable subscription line to compute bills, engineering salaries, and the ongoing time cost of keeping it running.
The ongoing engineering commitment
Building a link shortener is a project. Running one is an indefinite commitment.
Someone has to own it. That means monitoring uptime, managing database performance as link and click volumes grow, debugging failures when they happen, and handling requests from internal teams who want new features or better analytics. At minimum, that's one engineer with a meaningful portion of their time committed.
And the feature list grows. A basic redirector handles one use case. Add the requirements that come with enterprise use — bulk link creation, traffic routing rules, permissions and access controls, a management dashboard, UTM parameter handling — and you're looking at months of additional development on top of the initial build. Every feature added is a feature that needs to be tested, maintained, and updated as your infrastructure evolves.
AI lowers the cost of building. It doesn't lower the cost of running.
Teams increasingly assume that because AI makes the initial build faster and cheaper, the case for building in-house has improved. But that's only part of the picture.
AI didn't change the cost of the infrastructure underneath. Storage, compute, and data transfer costs are what they are. AI didn't reduce the operational complexity of running auto-scaling at high traffic volumes, or the engineering time required to maintain a system your business depends on.
AI shortened the time to a working prototype. The gap between a prototype and a system you can bet a campaign on is where most of the real cost lives.
What goes wrong when it fails
Nobody thinks about their link shortener until it goes down during a campaign launch.
Everything looks fine until you launch a campaign at scale. An email hits a million inboxes, or an SMS blast goes out to your entire database. Suddenly, your link shortener is handling a volume of traffic it was never stress-tested for.
Auto-scaling sounds like it solves this. In practice, tuning auto-scaling policies takes time and real production data to get right. While you're figuring it out, you're either dropping traffic or running far more infrastructure than you need — and paying for both outcomes.
At the volumes enterprise teams operate at, even a 0.1% error rate is meaningful. That's thousands of failed redirects per million clicks, happening to real users in the middle of real campaigns.
If your infrastructure drops traffic or returns errors in the middle of an SMS send or email campaign, you're not just dealing with an outage — you're dealing with broken customer experiences, lost conversion data you can't recover, and the downstream effects on decisions made using that data.
The cost of a single major outage can easily exceed what a year of enterprise link management software would have cost. That's worth considering before you start building.
Skip the build. Use ours.
At small volumes, a homegrown link shortener is manageable. As scale increases, so does everything else: infrastructure complexity, engineering overhead, and the cost of failures. Even teams with the budget to build usually find the ongoing commitment isn't worth it when a purpose-built solution exists.
Rebrandly handles hundreds of thousands of redirects per second, with autoscaling infrastructure built for unpredictable traffic spikes — and has spent years solving the problems that only show up at scale: bulk link creation, analytics, routing rules, and access controls.
That infrastructure has been tested at real scale. Wonder Cave, an SMS automation platform, needed 100,000 links generated in ten seconds for a single campaign send. Rebrandly delivered them in one second. Today, 97% of their campaigns run on Rebrandly-managed links — and their clients are seeing 60% higher click-throughs and 30% more conversions.
If you're evaluating whether to build or buy, talk to our team. We'll show you how Rebrandly handles link infrastructure at the volumes you're planning for.
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