Wais Swipe: Your Custom GPT for Choosing the Best Credit Card Every Time

So you’ve read my previous blog post and decided to follow in my footsteps (hopefully with a more manageable amount of cards). You’ll quickly realize what a pain it is to have to figure out which card to use for what purchases. At the end of the month when I’m reviewing my spreadsheet and seeing how much cash back I received, it irks me when I see I only received 1% cash back when I could have gotten 2%, 3%, or even 5% back for a purchase!

How do you know which card is the best for different purchases? There are some cards that are good for “Entertainment” such as the Capital One Savor card or cards that are good for “Transit” such as the AMEX Blue Cash Preferred card. Digging into the AMEX card further, you’ll see that their website says “Transit includes taxis, rideshare, parking, tolls, trains, buses, and more.” What is the “and more” referring to?

The key to determining whether a purchase is going to fall into a specific category is the Merchant Category Code (MCC). Every merchant that accepts cards is assigned an MCC (a 4-digit code) that describes its primary business type. For example, when you make a purchase, Amex reads that MCC and assigns the transaction to a category (e.g., groceries, gas, transit, streaming).

There are ways to look up the MCC using different online tools. For example, you could use the website https://awardwallet.com/merchants. But let’s be honest, not many people have the time to open up a browser, navigate to the website, look up the MCC for a merchant and then try to remember which of their cards would maximize the rewards. I certainly don’t.

Here’s where I think a Custom GPT in ChatGPT could be a huge time saver. Follow the steps to below to create a custom GPT that you can ask to help make quick decisions on which credit card you should use!

• 1) Edit this template with your credit card cashback categories

  You are a rewards optimization assistant. The user owns the following credit cards and wants to maximize cash back or reward points when making a purchase.

  Always recommend the card that gives the highest value based on the type of purchase. If multiple cards offer the same rate, prefer the one with simpler usage (e.g., flat rewards > category-dependent, unless the difference is meaningful).

  Only recommend cards the user already has. Do not recommend cards they don't own.

  Here is the user's wallet:

  Replace everything below with your own cards. Follow this exact format:

  1. Card Name

     • X%: category 1

     • X%: category 2

     • X%: category 3

     • X%: all other purchases

     • Notes: annual fee, travel portals required, Prime needed, spending caps, credits, etc.

  2. Card Name

     • X%: category

     • X%: category

     • 1%: other

     • Notes if needed

  (Continue for all your cards.)

  When asked what card to use for a purchase, infer the correct merchant category (e.g., streaming, groceries, gas, retail, etc.) and recommend the best match based on the user’s current cards.

  If no cards give a category bonus, default to the user's best flat-rate card.

  When relevant, explain how you determined the category.

  Do not suggest opening new cards.

• 2) Create a custom GPT in chatpgt

  1. Open ChatGPT

     • Go to chat.openai.com and log into your account.

  2. Go to “Explore GPTs”

     • On the left sidebar, click Explore.

     • Then click Create a GPT.

  3. Set Up the Basics

     • Give your GPT a name.

     • Add a short description of what it does.

     • Paste the instructions you created in Step 1.

  4. Publish

     • Choose whether it should be private, public, or unlisted.

     • Click Publish.

  5. Use It

     • You’ll see your GPT in the My GPTs list.

     • Click it anytime to start chatting.

• 3) Ask your custom GPT which card to use for purchases

  You’re ready to go!