Buyer Quickstart

Welcome to WaterMelonMarkets, the decentralized marketplace for buying and selling gift cards using our unique escrow contract, SafeEscrow. This Quickstart is best for intermediate web3 users (if you have used Metamask or similar at least once before) -- it gets you going in 1 to 10 minutes. If you are a beginner, we strongly recommend that you first glance through the below, and then read the Detailed Guide here. The Detailed Guide has similar structure to the Quickstart, but in much more detail.

If you prefer a full video walkthrough, please see our 20-minute full Video Walkthrough below.

Getting Started: Acquire USDC-Polygon and MATIC

Step 1: Buy MATIC Tokens on an Exchange (e.g. Coinbase)
  • 1A: Go to a Centralized Exchange like

  • 1B: Search for MATIC on Polygon, sometimes just called "Polygon"

  • 1C: If you have an option, ensure it says "Polygon" and not "Ethereum" (ignore if no option exists for you)

  • 1D: Buy an amount of MATIC whose dollar value is about $1-$2 more than the Selling Price of item you are buying. For example, if you are buying a $50 Face-Value gift card with Selling Price of $30, buy $32 worth of MATIC.

Figure 1.1: How to buy MATIC on

Video 1.1 Click Here to watch a video of the above

Step 2: Transfer MATIC to your Web3 Wallet (e.g. Metamask) Using Polygon
  • 2A: Hit "Send and Receive" and then put the amount you just bought ($5 in the below example) in the dialogue.

  • 2B: Ensure the "Asset" line says "MATIC" or "Polygon". IMPORTANT: Ensure the "Network" says Polygon and not Ethereum.

  • 2C: Double check the "To" line has your exact Metamask address. Then hit "Send Now".

Step 3: Ensure your Web3 Wallet (e.g. Metamask) Receives Your MATC
  • 3A) Open up Metamask (fox icon), usually an icon in the top right of your Browser (Chrome)

  • 3B) Choose the right account that you sent MATIC to.

  • 3C) Select the right chain, which is Polygon. If you don't see Polygon after a minute of trying, we suggest you follow this extensive guide.

  • 3D) Go to Activity, and you should see the exact number of MATIC tokens you sent before:

Step 4: Convert your MATIC to USDC-Polygon

You can do this in a variety of decentralized exchanges (dexs), but in this example we will

4A) Go to

4B) Change your chain to Polygon

4C) Put MATIC as the token you're trying to convert. And for target token, choose USDC-Polygon. Convert about 1-2 cents more than the price of the item you're buying. (USDC-Polygon is known on Matcha.XYZ as "USD Coin (PoS)".

4D) Hit Convert, confirm in Polygon, and you're done!

Click here for video.

Your First Purchase: Step-by-Step

Step 5. Go to, find a card you like, and click Buy
  • 5A) Go to our site, browse through brands you like, and click on one.

  • 5B) Find the card that you like

  • 5C) Hit the Buy button

Step 6. Go through the Checkout Process
  • 6A) Enter your email (to receive notifications and your card)

  • 6B) Connect your wallet to the site. Ensure it is Polygon and has the funds you need.

  • 6C) Increase your USDC allowance. (This is a standard step all sites require; hitting this does NOT spend your USDC yet). Wait for that IncreaseAllowance transaction to finish

  • 6D) Then click Initiate Transfer. Approve and wait for that InitiateTransfer transaction to finish.

For a video version, see the video clip here (please note that the video does not show Metamask, you'll need to follow the voiceover instead).

Step 7. Await Delivery and Finalize Your Transaction!
  • 7A) For Verified Transactions (most gift cards), you should receive your card immediately within 5 minutes. If the redemption info doesn't show up on your screen, also check i) your email and ii) login to your profile and look at your transactions -- it's usually all there.

  • 7B) For Deposited Transactions, you should wait for 1 business day to allow the seller time to manually send it to you. The card should be in your email or after you login.

  • 7C) In the unlikely case the card is late or no good, you may email for help.

  • 7D) In the more likely case the card works, go to your profile page after you log in to release funds!

Video Walkthrough

The following video walk through overlaps with the above, and may be better for users who learn better via video:

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