For many mid-sized companies, an API exists somewhere in the system. It might have started years ago as an internal tool. Maybe it was built quickly to satisfy a one-off partner integration. Over time, it stayed in place, but the company changed. Teams grew. Partnerships became more valuable. And suddenly, the API became a commercial asset.

That’s when the trouble starts.

Everything seems fine at first. The endpoints respond. Authentication is in place. The system behaves as expected. But when a partner tries to integrate, they get stuck. Support tickets appear. Someone from your team jumps on a call to walk them through it, again. The timeline slips. What looked like a simple integration now eats up hours of internal effort and days of back-and-forth.

The real issue isn’t the API itself. It’s how clearly it’s documented. Or more often, how unclear and fragmented the documentation has become over time.

The good news: You don't need a rebuild

Most legacy APIs don’t need a full rewrite. But they do need to be understandable to people who have never seen your system before.

Good documentation reduces friction, shortens integration timelines, and allows your internal team to step back from handholding every external partner.

If you want to shorten integration timelines, reduce support load, and build stronger partnerships, here are some of the most impactful improvements you can make - none of which require rewriting the API itself.

What to improve, and why

Start with real-life examples. Abstract field definitions are useful, but they don’t replace actual sample requests and responses. Developers don’t read API docs top to bottom. They look for something they can copy, tweak, and run. Including example payloads makes it immediately clear what a “valid request” looks like.

Next, create a simple “getting started” guide. This is not a spec. It’s a short page that tells a first-time user how to authenticate, where to send their first request, and what a successful response looks like. The goal is to remove uncertainty at the very first step.

Improve how errors are explained. Your system may already return proper status codes, but what does a 422 mean in your context? Why might a 401 appear unexpectedly? When the documentation doesn’t explain this, developers are left to experiment and guess, which leads to delays and support calls.

If you don’t already have one, publish a changelog. This can be as simple as a Notion page or a section in your Git repo. It doesn’t need to be exhaustive. But a visible record of what changed, when, and why gives partners confidence and prevents surprises.

Finally, consider offering a test environment. This might be staging credentials, a mock server, or even a shared Postman collection. The goal is to give external developers a safe space to experiment - without needing to wait on internal access or risk touching production.

You don't need perfect APIs. People need to understand them

The goal here isn’t to make your API beautiful. It’s to make it usable. Most integration delays aren’t caused by complex backend logic. They’re caused by confusion, missing context, or silent assumptions in the documentation.

And unlike a full rewrite, most documentation issues can be resolved within days - not months.

Want to go deeper?

If you’re unsure where to start, I also offer short API design clarity sprints for mid-sized teams. These are focused reviews aimed at identifying friction points and quick wins, which is especially helpful for legacy APIs that weren’t designed for partner use.

Feel free to get in touch if that’s something you’d like to explore.