Building Against Real APIs Is Nothing Like Reading the Docs

Jan S. — Mon, 03 Aug 2026 08:30:12 +0000

A few months ago, I started spending a lot more time working with different APIs.

At first, I thought authentication would be the hardest part. Once OAuth was working and I could successfully make requests, I assumed everything else would mostly be connecting the dots.

It didn't take long to realize I was wrong.

The real challenge wasn't getting data. It was figuring out what that data actually meant.

The docs only show the happy path

API documentation is usually great at helping you get started.

You learn how to authenticate, which endpoint to call, and what a successful response looks like. Five minutes later, you're making your first request and everything feels pretty straightforward.

Production is a different story.

One API returns timestamps in UTC. Another uses your account's local timezone. Some return an empty array when there's no data, others return null, and a few simply leave the field out entirely.

None of those things are difficult by themselves.

The challenge is that every API is a little different, and those small differences slowly pile up.

The same event can mean different things

One thing that surprised me was how differently platforms describe the same event.

Let's say someone asks:

"How many customers signed up yesterday?"

It sounds like there should be one answer.

But depending on which platform you're looking at, "signed up" might mean:

created an account
started a free trial
verified an email
completed a payment
became an active customer

None of those definitions are wrong.

They're just measuring different moments.

That was probably the biggest mindset shift for me. Before combining data, you have to understand what each system is actually measuring.

Expect inconsistencies

After working with more integrations, I've stopped expecting APIs to behave the same way.

Different pagination styles.

Different rate limits.

Different error responses.

Different field names.

Sometimes even different behavior between endpoints from the same provider.

At first those inconsistencies felt frustrating.

Now I almost expect them.

Instead of assuming every response will match the documentation, I try to build integrations that can handle missing fields, unexpected values, and the occasional edge case.

It's usually those small details that save you hours of debugging later.

The biggest lesson I've learned

If there's one thing I'll carry into future projects, it's this:

Treat every external API as a system you don't control.

The documentation gets you connected.

The real work starts after the first successful request.

That's where you begin learning how the API behaves in the real world, and that's where most of the interesting engineering problems show up.

I'm still learning this myself, but it's already changed how I approach integrations.

I'd be interested to hear what unexpected API quirks you've run into. I'm sure there are plenty I haven't discovered yet.`

DEV Community: Jan S.

Building Against Real APIs Is Nothing Like Reading the Docs

The docs only show the happy path

The same event can mean different things

Expect inconsistencies

The biggest lesson I've learned