DEV Community: Rodrigo Eloy

Fixing a 5 Million Request Problem with GraphQL and Caching

Rodrigo Eloy — Wed, 13 Aug 2025 20:53:52 +0000

Last month, our Contentful usage exploded to over 5 million requests… and we hadn’t even launched yet.

Hi guys, I know I’m not the most consistent poster, but I want share with you how we debugged this mystery, saved hundreds of dollars, and I learned to love GraphQL along the way.

"GraphQL" — have you ever heard of it?

I’d been hearing about GraphQL for quite some time. I’d read about its potential benefits, but I could never find a solid reason to replace my regular REST APIs with it… until a few weeks ago.

If you're interested, you can check out more about what GraphQL actually is with this amazon article: GraphQL vs REST

Quick context

I’m currently working as a Software Engineer at Observatório da Caatinga e Desertificação, where we’re building an open data platform to raise awareness about socio-economic and environmental indices about Brazil’s Northeast region. The project is funded by this governmental regional development agency called Sudene.

After some discussion, we decided to use Contentful as our Headless CMS instead of hosting our own or creating an API that connects to our own database. The reasons for that choice aren’t important right now, but feel free to reach out if you want to chat about it. <3

Contentful's usage

Contentful’s free tier allows up to 100k requests per month. “Great,” we thought. “Plenty.”

Turns out... not so much.

After hitting that limit for a couple of months in a row, our bill would jump $300. Not a massive number, but every penny counts haha.

Then one day, we got a warning: we had already blown past our free tier limit for the month. And this was before launch!

Five million requests?!

Yep. Five. Million. Requests. In a single month.

“What happened?? We haven’t even released the platform yet!” That was everyone’s reaction.

We started debugging. Then after a while, we finally got a solid lead.

The causes

First, we noticed two health check monitors (Route53 and Blackbox) pinging our beta and main apps every 30 seconds from six regions worldwide. The problem? They were hitting the home page, which triggered content fetching.

Fixing that was easy: we added a /health route that returns a simple response.

That explained some of the extra requests... but not the million. We still had half the puzzle to solve.

The second cause? Our own code (of course haha).

Contentful’s regular client can’t query multiple entity types in a single request, meaning we had to fetch them one by one. And you know what that means, right? Yep — some of our pages had a LOT of different entities, in some cases we had almost ten requests per page.

Now, let’s do the math:


// we added a 1-minute revalidate in so it only fetched Contentful once per minute
minutes_per_day = 1440 

// because we checked the home page:
health_check_queries = 8 
regions = 6
days_per_month = 30
monitors = 2

requests_per_month = 1440 * 8 * 6 * 30 * 2 -> almost 5 Million

The math was mathing.

Now, how to fix it?

Holy GraphQL

This is when I finally got why people love GraphQL.

With the regular client, I had to make separate requests because I couldn’t control how the external API worked. Making weird fix to request everything wasn’t an option — and even if it was, it wouldn’t have felt very elegant with the resources I had.

With GraphQL, I could ask for exactly the entities and attributes I needed, all in one query (within Contentful’s complexity limit).
That took our requests per page from 8–10 down to an average of 2.

But even with GraphQL in place, those misconfigured monitors hinted at another future problem: success.

The holy trinity

If the platform does well (fingers crossed 🤞), more traffic means more requests. And if every time a user visits Data Nordeste we hit the API — even with GraphQL — we’d run into the same problem eventually.

The fix we got? Caching.

We used nginx to cache the HTML rendered by Next.js on the server, and Apollo's GraphQL caching on the client side.

The outcome: from 6 million requests in July to 24,000 these next months (estimated).

Now, what did we learn today?

I know this might seem trivial to some of you with more experience, but I love this kind of challenge. Having a problem that NEEDS to be solved and engineering a solution is exactly why I love this career so much.

I really enjoyed learning more about GraphQL and caching. Next, I want to build a backend using GraphQL to see how it really works — maybe I’ll write another post about that soon.

Thanks to my team at OCA — working with you guys is amazing. ❤️

It's all character development, guys

Rodrigo Eloy — Mon, 09 Jun 2025 01:41:17 +0000

I recently came to realize that every failure is also a new opportunity for learning. I know, maybe that's an obvious cliché, right? And no, I'm not trying to be corny or anything, just hear me out for a second...

If you've read one of my previous posts, you'll know that I'm trying to land a position as a software engineer. Ever since I started worrying about getting into a company, I've gone through a lot of hardship, coming to the realization that this is by no means a chill path to follow.

500 Problems Solved Must Be Enough

I've been studying LeetCode problems for the last six months. I've solved more than 200 questions and revisited them over 500 times—literally.

By the time I applied for a position at Amazon, I was pretty confident in my ability to solve almost any LeetCode problem they threw at me.

All that confidence, just for life to knock me down and humble me all over again.

I Couldn't Even Get Past the Front Door

Yeah, as you might expect based on how this narrative is going, I did not do well.

The first step in the process was an Online Assessment: two problems in 70 minutes.

"No problem for me," I thought. "I've been training for this every day!"

But I wasn't counting on one important variable in this huge equation: anxiety.

Unfortunately, that day, I didn't solve a single question. It was incredibly frustrating. All this time studying specifically for these scenarios, and still, I couldn't do it. "What a waste of time," I thought to myself that day.

Failing is most times THE Learning Process

After letting myself feel all the frustration and anger for a while, I decided to do what I intended on doing when I first applied to Amazon: take notes on how to improve. So, I did.

I came to understand that I get really nervous in these situations; my mind gets foggy, and I freeze up. I realized I needed to learn how to remain functional while nervous, because the nervousness itself wasn't something I could easily control.

It's Still Frustrating, Though

Yeah, even knowing all this, not getting through technical interviews is still frustrating. But now I understand that I didn't fail and went back to square one. Instead, I failed and went back to the closest checkpoint.

And I know that by getting through it checkpoint by checkpoint, I'll eventually get where I want to be—even if it takes more than a few retries.

Plot Twist: I Didn’t Get the Job (Yet)

Rodrigo Eloy — Sun, 11 May 2025 02:10:55 +0000

Hi again everyone! As I hinted in the previous post, I wanted to share not only my journey of re-learning to love learning, but also my “landing my first proper job” journey—while I’m still navigating through it. So, let’s start from the beginning.

Yeah, it's what you would expect: I couldn't land any job openings

A little context: during my last CS semester, I was working on a project at UFCG in partnership with Nubank, which was honestly really great. But on my final months there a little alarm went off in my head:

“I’m graduating this semester, man—I gotta land a job ASAP.”

I started by asking a friend who works at Google for her CV (I thought that if she landed a job at GOOGLE with that CV format, it must be a great one, idk, as if that was the decisive factor haha). Then I just started applying to every job opening I could find, even ones I didn’t really want. I was desperate.

Then something caught me off guard:

Barely any company replied…

I was devastated. No, seriously—back when I started college, people were landing jobs after doing a bootcamp for a month or so. But the market had changed, and over the next few months, it showed me just how wrong I was for thinking it would be easy.

That hit me hard. I couldn’t land the jobs I wanted, so by the end of last year I figured—if it’s going to be this hard, might as well dream big.

What if I aimed for the stars?

Since my very first week in college, I’ve always dreamed about what it would be like to work at Google. In my CS baby brain, the work they did always seemed so magical and effortless.

The magical fog faded, but the dream stayed.

The thing is, I never really saw myself as the kind of person who gets hired by big tech companies.

I wasn’t the kind of person who could express themselves clearly in English (so writing this in English is already huge progress for me!). I didn’t know advanced algorithms inside out. I thought that kind of thing was just for outliers—and I never saw myself as one.

But something changed in November 2024...

No, I didn’t suddenly believe in myself—I got desperate 💗

Just kidding, I actually got desperate—but I also started to believe, just a little.

Seeing people close to me land jobs at these Google like companies made me realize: I might not that special… but I do need to start working toward what I want.

So, I got myself enrolled in an English course (which I’m loving!) and started studying LeetCode problems. I’ve been doing that for the past six months, and honestly? It’s been a surprisingly fun ride.

Yes—I got into AA (Advanced Algorithms). I know, wild. But I’ve actually started to enjoy it, and NeetCode’s website has helped me a ton.

Turns out, I’m a spreadsheet geek

Quick break in the story: to track my progress and figure out what kinds of problems I should target next, I created this Questions Tracker Sheet, where I log every question I solve and how much time it took.

I've solved a fair bit, which is far beyond what I thought I would get. I think I may write a whole post about this LeetCode thing any day soon.

Okay, let me wrap this up

No, I haven’t landed a position yet. But I’m working on it, you know? And the feeling that I’m doing everything I can — that’s been a really comforting one to hold on to.

The truth is: I’ve learned more than just English and algorithms.

I’ve learned that I can do this. That I am capable of learning and committing to something I truly want.

I also realized that yeah, working at Google would be amazing—but what I really want is to work somewhere that makes me feel good, where I earn my own money and feel like my work matters. But still, Google could probably be this place for me... so Google, please hire me haha.

Thanks so much for reading! Hopefully one day I’ll write a post here explaining how I landed a job at <company's name> and why I love working there.

See you soon.
Xero

I Thought I Had It All Figured Out... Until I Didn't

Rodrigo Eloy — Fri, 02 May 2025 14:48:18 +0000

Can't believe I'm finally doing this!

I've always wanted to write a blog and create a tech YouTube channel — I think having a blog will have to be enough for now.

A little background for you

Well, my name is Rodrigo. I'm a recent CS graduate, and honestly, I'm just trying to understand where I fit in all of this.

I've always done a lot of things during college — organized events, created personal projects for the CS community at UFCG (which is the university I graduated from), and even joined a handful of partnership projects between the university and different companies.

It was great, don't get me wrong. These were amazing experiences. But by the time I reached my final semesters, I thought I had everything figured out. I knew how to get into projects, how to organize events that really worked, and I felt like there was nothing left for me to do. I thought, "I had done it all!"

But later I came to realize I was actually just tricking myself.

I got tired

I thought the feeling I had could be defined as "wholesome" somehow — like I had done everything, and now my journey was just maintaining what I had achieved.

Unconsciously, though, I was fooling myself so I wouldn't have to learn anything new. I joined projects doing things I already knew, or things that required the least possible effort to learn.

I just got tired of everything, I guess.

I ran out of fuel — stopped learning, stopped creating, stopped doing exactly the things I always said I loved about CS.

But not anymore!

So what's this blog for?

Now, almost a year after graduating, I realized I want to rediscover what I really like and find myself again in this career. I hope to get back to learning new things, challenging myself, and trying to solve daily struggles with technology — and hopefully, land a job at a company I like (just a hint for my next post 👀).

This blog came to me as a first step on that journey, like breadcrumbs along a path I want to create for myself. So if I ever get lost again — which will probably happen — I can look back and remember why I started and where I wanted to go.

That’s why I’ll use this platform to document and share the things I learn and the insights I gain along the way.

Hope you’ll stick with me on this journey.

Xero