Welcome to OpenSea's CryptoKitties Guide! Here you will find useful links for both the trading platform and the game itself. Enjoy!
Resources taken from and the CryptoKitties Discord channel.
CryptoKitties are collectible and breedable digital cats. It’s the world’s first game built on the Ethereum network. When two CryptoKitties breed, their offspring’s appearance and cattributes are determined by each parent’s 256-bit genome and an element of chance, leading to 4-billion possible genetic variations.
CryptoKitties was created to explore the concept of digital scarcity, implement a non-fungible token within smart contracts ERC #721, and make blockchain technology accessible to everyday consumers.
See the Getting Started page for details on preparing to play the game!
Join us on the DISCORD SERVER:

Getting Kitties

Check out the OpenSea Marketplace at or purchase kitties from In addition you can Breed your own kitties amongst themselves (if they're not related), and or you can breed your kitties with other user's kitties (users can 'Sire' their kitties).
For detailed information on buying and selling kitties from the OpenSea marketplace, check out the Buy and Sell Kitties section of this Wiki.


There are 2 main activities in CryptoKitties: Breeding and Siring. These are the way in which rare kitties come into existence for the most part. As Kitties Breed, they get less and less effective at doing so each time by design. This makes rare kitties that can still breed extremely valuable. When these high tier kitties become so slow to breed that they retire, their offspring will typically take the title of 'most valuable'.


Breeding in CryptoKitties is designed to act like breeding in real life with respect to the passing down of traits / genes. There is a Dame (the female kitty which will birth a new kitty) and the Sire (male kitty). Any kitty can play the role of Dame/Sire, but you cannot perform both activities at the same time. Both the Dame and Sire's genes are mixed together to produce a new kitty. Just like in nature, some traits are recessive, and some skip generations. When breeding, you choose one of your kitties to be the Dame. You must also choose another one of your eligible kitties to be the Sire, or rent one from another user, via the CryptoKitties marketplace. Breeding is performed via the CryptoKitties website
As example, let's breed one of JBDoge's Kitties as a Dame with another user's Sire! First we'll go to our 'My Kitties' page (
Coolio is eligible to Breed, so we'll click on her, taking us to Coolio's CryptoKitties page. She is a 15 Gen kitty which isn't great, but she has some excellent traits, and is quite beautiful! Her parents were quite beautiful as well. Note that she has a 'Plodding' cooldown, so it will take some time for her baby to be born.
You'll notice that some of her Cattributes have gems in them. This indicates that this Kitty is a direct descendant of the first Kitty to have those traits (this will be a generation Zero kitty). Coolio looks like she may yield another beautiful cat, so lets look for a kitty to breed her with.
We'll head to the CryptoKitties marketplace and click on the siring tab ( There are many filters, but let's try to find another kitty with Henna markings on them. We'll type 'henna' in the search bar, and sort by 'Cheapest'. After looking through the results, JBDoge finds a Sire (Kitty #524919) he wants to mate with Coolio, and decides to breed.
Let's click the 'Breed Now' button. This will take us to a new page where we must select our Dame, in this case Coolio.
Clicking "OK, give them some privacy" will give us a Metamask transaction pop-up which we must SUBMIT to actually start the breeding process. Note that the owner of the Sire (Mittens), will receive 0.004 ETH, but there will also be a 0.008 ETH CryptoKitties fee for breeding. This brings the total cost 0.012 ETH + Ethereum network transactions fees (actual Transfer cost was 0.00021846 ETH).
We wait a few minutes for the transaction to complete, and now if we go back to the 'My Kitties' page we can see that Coolio has a 'bun in the oven'. Her offspring will be born in 3 hours.
A few hours later...
YAY! We just received an email from the CryptoKitties team, letting us know our baby kitty has arrived! Let's take a look:
We can see that our offspring has gotten a very nice split of genetic traits directly from its parents, which is not terribly unexpected given how similar they looked to begin with. Here's a visualization how the traits were distributed:
We'll give our new kitty a name by clicking on her name tag overwriting the default name of "Kitty 529106". Let's name her Queenie. You can view her directly on the CryptoKitties site here:
For even more in-depth breeding strategies, check out the Advanced Breeding page


Siring is a way to earn money from your rare kitties, without selling them. You essentially 'rent' them out to another user, to get the other user's kitty to have a 'bun in the oven'. This is actually far easier than breeding. Your main considerations are:
NOTE: Since there is a transaction fee to list your Kitty, you will lose some money if nobody breeds with your Sire. This is why it's important to make sure you have a rare, but well-priced Sire. Let's sire our new kitty, Queenie! First we'll go to her kitty page ( and click the 'Breed' button.
This will take us to a new page, where we can either Sire Queenie to the public, or to our own kitties. For this example, we're going to try and recoup some of our money from the Breeding session above, by Siring Queenie to the public. Since Queenie's generation isn't so great (16), we're gonna sire her for the same price we paid to Mittens (owner of Kitty #524919). We'll list Queenie's 'services' for 0.004ETH, for 30 days.
Once we've got the terms set, we'll click 'Done' which will generate a Metamask transaction. We'll SUBMIT that and wait for the Ethereum transaction to complete. Once the transaction is complete, we can view our active Siring activity on the CryptoKitties site (
A few moments pass
Interesting, we just received an email from the CryptoKitties team. A user has already Sired with Queenie after just a few moments on the market!
And sure enough, 0.004ETH was deposited into our wallet. YAY!
Last modified 3yr ago