Custom Card Creation: A Guide to Playtesting

If I had to name one thing which I believe is undervalued and underused in the mtg custom card community it would be playtesting.
I’ve seen dozens of talented designers create and iterate on great designs for mechanics, duel deck and whole sets. But when asked what playtesting has been done all to often the answer is “very little.” I understand why this is, playtesting is hard, time consuming and it isn’t exciting like creating the next cool card. This is then exacerbated by the difficulties of getting  lots of players together and a lack of step by step resources on how organize these playtests.

In this guide I’m going to run step by step on how to coordinate your own both physical or online playtest sessions so you can improve your custom card designs.

Physical Playtesting

Doing physical playtests involving proxy cards, creating boosters and then playing draft or sealed events is by far the most rewarding and productive method. However it can be difficult to setup, expensive and time consuming and thus I usually only rely on this method as my custom set is getting closer to completion.
The general setup of my paper playtests is to do draft or small sealed events of 6-10 players with high quality color proxies that are sleeved in front of a regular magic card to give it weight and rigidness. I then sort these by rarity and arrange these into booster packs to create events as similar to a regular MtG event as possible.

Note that there are actually many different ways to do this kind of playtest such as stickers, unsleeved cards or manually creating lower quality proxies. However I’ll be going step by step on how I personally do it so you have a guideline to follow.

Final Product of the playtest
24 booster packs and sleeved lands for my Dreamscape playtest

What you need:

  • Your cards on Magic Set Editor
  • PDF printing software (such as CutePDF)
  • Lots of card sleeves
  • Old magic cards to use as sleeve backing
  • Rubber Bands
  • Basic Lands
  • Several hours spare time
  • Friends or LGS players to play with


The first thing I need to do is make PDF documents of the card sheets for easy printing. To do this use the print option of MSE2 with CutePDF writer, this takes a bit of time to render but I end up with clean sheets like THIS ready to be printed professionally. If your doing a lower quality playtest or you have access to a high quality printer you can use the MSE2 print option directly and cut out the need to create PDF documents.

For a full print run to create 24-30 boosters I usually print two or three copies of each common (202-303 cards) + 50-150 random commons, 120 uncommons and 30 – 40 rares/mythics. This gives me enough cards for all the packs plus a little extra for variance. Also be sure to print extra copies of cards that you want to test specifically if they have undergone major changes recently or are on your watch list as potentially unbalanced or unfun cards. Another reason I print extra cards is that the random generator inbuilt into MSE2 isn’t the best and creates clumps of the same card while giving you no copies of others.

Once I have PDF’s of all the cards I want printed I take them to a printing shop like Officeworks and have them do color printouts and guillotining. For my cards I use 200gsm bond paper which is slightly thicker than normal paper to make them easier to sleeve and harder to damage.
Now be sure to get a test sheet printed if possible as I always have to have the printer lightness settings increased by 10% otherwise the cards turn out too dark, however this will change depending on the printer. Finally Officeworks also guillotines them for me, saving me a huge amount of time cutting out cards for only a few extra dollars.

In total printing of this quality and quantity as well as the  guillotining will set me back about $40-$60 but will save me huge amounts of time. Printing and cutting a set for a full draft by yourself will not only give you a lower quality product but also can take days of work.

Paper prined cards
A scattering of card printed, guillotined and ready to be sleeved

Creating Boosters

The next step is to sleeve all our custom cards. I just buy the cheapest sleeves I can, put a junk common normal magic card in them and then slip the custom card in front of the real magic card. This can be somewhat time consuming but can be done while watching TV or other activities. Be sure to do this about a week before hand so that If you see any mistakes or haven’t printed enough then you have time to print a new small batch.While sleeving your custom cards sort them into piles based on rarity, this will make creating your booster packs easier.

Once all the cards you need are sleeved and sorted simply shuffle the rarity piles and then lay out the top 10 commons, then the top 3 uncommon, and then a rare or mythic. This will give you a very rough booster pack which you then want to check against a couple of simple rules that will help simulate how WOTC creates print runs and prevent color imbalances.

  • A pack must never have more than 4 commons of the same color
  • A pack must have at least 1 common card of each color
  • A pack must have at least 1 common creature
  • A pack must never have more than 2 uncommons of the same color
  •  A pack must never have repeated cards

Once the packs are completed tie them up with rubber bands, put them in a bag or box with any spare cards, plenty of spare sleeves and sleeved basic lands. Now you ready for the fun part of organizing an event and then getting to play your cards.

Online Playtesting

Online playtests use the Cockatrice card client and take far less time and money to setup compared to a paper draft. However it can take more technical knowledge to setup, but once done once you can easily playtest with nearly anyone.
The power of online playtests is how quickly you can iterate on your designs, quickly testing mechanics you are unsure of. For example I nearly always start my projects with online playtests as doing several weeks worth of work only to find your cards are absolutely unfun at the first playtest is a disaster. Quick online sealed playtests allow you to avoid this, are easy to setup (as you often only need two people), and you can ever prebuild the sealed decks to make this process even faster.
Recently playtesting custom cards online has become far easier due to the creation of the custom Webdrafter site by CommanderZ. What was once a tedious and technical process to setup sealed decks has now become easier and it even allows you to draft your sets online which was nearly impossible previously.

What you need

Packaging your set

The first thing we need to do is create a zip file package of our set that we can share with others to easily play our cards on Cockatrice. This package will contain a .XML card file, a folder of card renders, and a read me to give directions on how to use the package.

The first thing to do is make sure we have both the MSE exporters correctly added to MSE. Make sure you have downloaded the exporters and extracted them to the MSE’s data folder found at: C:\Program Files (x86)\Magic Set Editor 2\data

After restarting MSE, go to File -> Export -> HTML and export your set with the Cockatrice Exporter, being sure to enter your set code and leave the “images location” field blank.
Exporting the MSE file
Exporting Dreamscape with the exporter

The exporter will save a your .XML file for Cockatrice to read but you still need to export your card images, in MSE File -> Export -> All Card Images…. is the option you want.
Export all the card images to an empty folder with the same name as your set code, using in the card format field. This will ensure that your images correctly import into cockatrice at the best quality.

Finally zip both the image folder and the .XML file together an add a readme for others to follow, as well as any credits or notes.
You can find an example readme here which you can use as a template.

To install your set onto cockatrice put the folder full of card images into the cockatrice pic directory
This is usually in the app data location:
or in your main cockatrice folder
Then put the .xml file in the customsets folder usually found at:

When you restart cockatrice it should mention detecting a new cardset, accept the prompt and your cards should now be available in cockatrice.

Uploading to Webdrafter

While we now have a custom set package we can share with others it is still very difficult to use this for playtesting any limited environment. So we need to now upload the set to Webdrafter which means players can play draft and sealed with our custom cards

Read this detailed tutorial on how to upload your set to Webdrafter

If you need help you can often find the developer or myself on the /custommagic IRC Channel where we can help you if you have any issues. Otherwise comment on the article if anything is unclear.

Once your set is uploaded you can go to “Browse sets” to double checked it worked and then login and Host a Game. Their you can choose different limited formats to host and then export your decks to cockatrice and play online using the package you made earlier.

Remember that no amount of theory crafting will beat frequent and varied playtesting. You will discover mistakes, imbalances and unfun mechanics, but in the end this iteration will improve your designs dramatically.

About the Author

Reuben Covington is a Melbourne games programmer, game designer and MtG enthusiast. He runs a podcast called Re-Making Magic about MtG custom cards and game design as well as works on projects such as his custom MtG set, Dreamscape.


Twitter: @reubencovington

Further Reading

Adventares: Creating custom booster packs

Webdrafter set import tutorial

  • For me, playtesting is a holy grail. It’s underused, yes, but far from being undervalued – it’s the one aspect of my custom sets that I’m achingly aware is hideously absent from all my sets.

    You say “playtesting is hard, time consuming and it isn’t exciting like creating the next cool card” – I wouldn’t really say that’s the problem for me. It’s really rewarding to see which of my custom mechanics work out fun, and to get feedback from others on which cards work and which ones don’t. It’s very exciting. The problem is, as you allude to next, it’s just really hard to get people together to actually do playtesting. Nobody else will be as enthusiastic about drafting my custom set as I am.

    This, incidentally, is one way that I think those of us in the custom set creation community really ought to be supporting each other more. I would dearly love to be in a community where maybe every week or two we do a draft of someone’s custom set, even if that was *my* set only one time in 8 or 10. That’d be awesome. What feels like it’s missing to me is the TOOLS to do so.

    However, I wasn’t aware of WebDrafter. Does that actually allow people to play with their cards, or does that have to be done via Cockatrice?

    Either way, it’s great to see tools coming along to fill in the gaps in this process. I really want to find some time to work on the MSE import/export for so that that can be another part of the workflow here. Providing a place where all players of a draft can easily record their comments on particular cards or mechanics, and discuss with each other, seems like something that the existing MSE / Cockatrice workflow doesn’t provide, and a niche that MagicMultiverse is perfectly suited for.

  • Eww, the commenting system here seems to have stripped out all my paragraph breaks. Never mind. Forgive me for what appears to be a wall of text – I assure you it was split into more readable paragraphs when I posted it.

  • Webdrafter is only supports the drafting section of the custom set, when the draft is over it provides a link to the custom set package for cockatrice as well as your decklist. However the games still have to be played over cockatrice. I agree that magic multiverse fills an important hole for group projects and I’ve been in slow discussions with its creator about more cross program support. I suggest you go give him a comment as if he knows the demand is there he will make it a higher priority.

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