Things I Learned While Integrating APIs in Next.js Projects

#react #nextjs #typescript #webdev

Hi everyone,

Over the last few months I worked on a few projects using Next.js with REST APIs. One thing I realized is that integrating APIs in real applications is very different from small demo projects.

There are many small issues that come up which you usually don't notice when learning Next.js for the first time.

I wanted to share a few things I learned while dealing with these situations.

1. CORS problems happen more often than expected

One issue I ran into multiple times was CORS errors when calling APIs.

Sometimes the API worked perfectly in Postman but failed in the browser.

At first it was confusing, but later I realized that the browser blocks requests if the backend doesn't allow the origin.

In some cases we solved this by updating backend headers, and in other cases we used Next.js API routes as a proxy.

That helped avoid the CORS issue completely.

2. Debugging API requests is easier with simple tools

While debugging API issues, I started using a few simple techniques:

checking the network tab carefully
logging request and response data
testing APIs separately in Postman

Many times the problem was actually small, like a missing header or incorrect request body.

These small checks saved a lot of time.

3. Handling loading and error states properly

When building real user interfaces, API calls don't always succeed.

Sometimes the request takes longer than expected or fails completely.

Using TanStack Query (React Query) helped a lot with this. It made handling loading states, caching, and retries much easier compared to writing custom logic every time.

4. Environment variables matter in production

Another thing I learned while deploying Next.js apps was the importance of environment variables.

Sometimes an API worked locally but failed in production because the environment variables were not configured correctly.

Now I always double-check .env files and deployment settings before debugging deeper issues.

Final thoughts

Working with Next.js in production applications taught me that most problems are not about the framework itself but about API integration, debugging, and handling real-world edge cases.

Each project teaches something new, and I'm still learning better ways to structure and debug applications.

If you have worked on Next.js projects and faced similar API issues, I would be interested to hear how you solved them.

Thanks for reading.