About CompTackle

CompTackle is a market research tool for resellers. You search for an item, and it shows the comparable listings that are live on eBay right now and how their asking prices spread out. Then you enter your own sold-item research, and CompTackle scores it with a Sell-Through Rate, an estimated time to sell and a Good / Maybe / Bad rating, so you can decide whether the item is worth buying.

It is built and run by one person, Mathew Valdez, an active reseller in Miami, Florida. You can read his story below.

How it works

  1. Search an item. Pick a category and item type, add the details that matter (brand, size, condition), and search. You can try it as a guest or create a free account to keep your history.
  2. See what is listed right now. CompTackle pulls current active listings from eBay and shows the spread of asking prices, so you can see the competition you would be up against.
  3. Add your own sold research. Enter what similar items have actually sold for. CompTackle scores your numbers and gives you a Sell-Through Rate, an ETA and a Good, Maybe or Bad rating.

What makes it different

Questions and answers

Is CompTackle affiliated with eBay?
No. CompTackle is an independent product. It uses eBay's public developer data and is not owned, sponsored or endorsed by eBay.
Does CompTackle show sold prices?
Not today. It shows current asking prices from active listings, and you add your own sold research to get a score.
Is it free?
Yes. Accounts have a daily search allowance. If paid plans are ever introduced, you will be told clearly before you are charged.
Who is behind CompTackle?
Mathew Valdez, the founder and solo developer, who also resells on eBay. His story and links are further down this page.
What happens to my data?
See the Privacy Policy. In short: no ads, no selling your data, and you can delete your history or your whole account yourself.

Meet the Founder

The Person Behind CompTackle

Mathew Valdez, founder of CompTackle, smiling at a Miami Heat game

Mathew Valdez
Founder & Independent Developer
Miami, Florida · FIU Computer Science

From Reselling to CompTackle

Hey! I'm Mathew Valdez, the founder and solo developer behind CompTackle. I'm a Computer Science student at Florida International University, an active online reseller based in Miami, Florida, and someone who has probably spent way too much time researching whether a random pair of jeans or an unusual collectible is worth picking up.

My interest in reselling started with something simple: the excitement of finding value in things other people overlook. Whether I'm digging through the Goodwill Bins, browsing thrift stores, or searching local marketplaces, I've always enjoyed the idea that an ordinary item could turn out to be something special. I've bought and researched everything from clothing and vintage pieces to electronics, toys, and collectibles. But as much as I enjoy finding inventory, I quickly learned that finding something interesting and finding something profitable are two completely different things.

The biggest challenge was always the research. I'd find an item, pull out my phone, open eBay, search for similar listings, compare prices, check different conditions, and try to figure out whether it was actually worth buying. Sometimes the answer was obvious, but other times I'd spend far too long searching for information that should've been easier to understand. A seller asking $150 for an item doesn't necessarily mean it's worth $150, and even a potentially valuable item isn't always a good purchase when you factor in competition, fees, shipping, and how long it might take to sell.

I've experienced both sides of reselling: the excitement of making a great find and the frustration of realizing something wasn't nearly as valuable as I initially thought. I've dealt with negotiations, slow-moving inventory, shipping headaches, and plenty of trial and error. It's rewarding, but it can also be unpredictable, especially when you're working with limited time and money. Eventually, I started wondering why researching potential inventory had to involve so many tabs, repetitive searches, and educated guesses.

Building Something of My Own

That's where the idea for CompTackle came from. As someone studying Computer Science, I wanted to see whether I could use what I was learning to solve a problem I personally dealt with. I began building a platform that could bring marketplace research, asking-price information, and competition analysis into one place. What started as an idea to simplify my own workflow eventually grew into a real web application. I developed CompTackle independently, working through the challenges of building, testing, deploying, and maintaining a product while continuing to attend university and resell.

Building CompTackle has taught me that creating software is about much more than getting code to run. I've had to learn about APIs, hosting, security, user experience, operating costs, and the limitations of marketplace data. There have been frustrating bugs, features I've completely rethought, and plenty of late nights trying to figure things out. I'm still learning, and I certainly don't have all the answers, but seeing something I created become an actual product has been an incredibly rewarding experience.

My goal with CompTackle isn't to promise that every purchase will be profitable or that software can replace a reseller's experience and judgment. I want to make research more convenient, accessible, and useful. Whether you're an experienced seller sorting through inventory or someone standing in a thrift store wondering if an item is worth picking up, I hope CompTackle can help you make more informed decisions. I'm an active reseller myself, and you can even check out my eBay store to see that I'm genuinely involved in the same market I'm building this platform for.

A Little About Me

Outside of reselling and developing CompTackle, I'm currently pursuing my bachelor's degree in Computer Science at Florida International University, with an expected graduation in Spring 2027. I've always been interested in technology, entrepreneurship, and finding ways to turn ideas into real projects. CompTackle has given me the opportunity to combine those interests while challenging myself to learn things I never expected to tackle as a student.

And when I'm not coding, studying, or hunting for inventory, there's a pretty good chance I'm playing video games. I've been a gamer for years and even have a YouTube channel called MathewGamer, where I've uploaded videos, livestreamed, and connected with other people who enjoy gaming. I'm also a huge Miami Heat fan, enjoy exploring new ideas, and occasionally find myself getting distracted by another project when I probably should be finishing the one I'm already working on.

At the end of the day, I'm just a regular guy from Miami who enjoys reselling, technology, gaming, and building things. I don't have decades of industry experience or a massive company behind me. I'm learning as I go, making mistakes, improving, and trying to turn something I genuinely enjoy into something useful for others.

CompTackle started as a solution to my own frustrations with reselling, and my hope is that it can help make the experience a little easier for you, too.

Thank you for being part of the journey.

Connect With Me

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