Keeping soft currency balances in check and examples of evergreen sinks

Even though the mobile business is relatively young compared to other entertainment industries, the times where hard currency could only be acquired via IAP are pretty much behind us (it doesn’t mean that approach to in-game currency and monetization should be dismissed altogether – having Mobacoins helped achieve some important monetization goals). Mainstream games might have loosened up on that front – in most games users can now acquire some hard currency without spending money – the hard currency/soft currency distinction still reflects a key difference. Items that can be purchased with hard currency are items that can be acquired relatively independently from the gameplay loop (you spend money to get them), whereas items that can be acquired via soft currency are items that are priced (and balanced) relative to gameplay actions and events.

I’m a big fan of casino/slots/poker games. One of the main strengths of those games is that playing the game and the reward you get from playing are on the same level. You spend x units of currency to play – your play rewards you with y units of that same currency. Ideally, you want y ≤ x. In slots/poker games that means you have more influence on user sessionning patterns. My experience in slot games is: I bet as much as I can, run out of coins (which are required to play), and come back after 2 hours when the login bonus provides me enough coins for one spin. Which I in turn lose instantly… Directly related to this, another great aspect of those games is that it’s easy to tune your game and ensure user balance stays in check. As soon as there is a mediation currency – take the example of an RPG game where users consume energy to play missions and get coins as a reward for those missions – user currency balance is something you need to be actively working on.

Why is this important? A lot of evidence suggests instrumental considerations are not the main motivation for conversion (the first IAP purchase), and not the only consideration for the repeat purchases of older and engaged users. But this doesn’t mean users are erratic and irrational. If users want to purchase something that costs 5k coins, and their balance is 20k, it’s very unlikely users will do an IAP to acquire the item they want. Even if you don’t monetize soft currency (which you should) – either directly via an IAP or indirectly by converting hard currency – you want your user balances to be stable over time and close to 0. That will ensure users need to keep engaging with the game to buy what they desire.


Keeping balances in check via in-game tuning

Very simply, balances are out of check when the influx of currency is consistently greater than the amount spent. To keep balances in check you don’t want users to get much more currency than they spend (it’s not materially possible for nonpayers get less currency than they spend – nonpayers can only spend what the game gives them).

You keep balances in check by tuning the game loop. The traditional sources of soft currency are mission rewards – if there are others it’s simple to account for them. Even if you have an energy system and there isn’t a direct currency cost to play, you can still put a soft currency cost on playing. This is where progression tuning comes into play. Imagine you are working on an FPS game. You maybe only need 1 energy unit to play mission 20. But you can tune your game in such a way that users will have needed to have spent 50k coins to upgrade their sniper to beat mission 20. So that means even though there is no soft currency cost to initiate a mission, there is a soft currency cost to beat the mission. In this case you would want to ensure the amount of currency received during the first 19 missions matches very closely – ideally less – the amount required to upgrade the sniper enough to beat the mission.

You can approach it per mission, session, day, or whatever other standard is relevant for you. When you are approaching things this way, you are effectively using game difficulty and progression to make sure user balances are in check. But there are two main reasons why tuning progression and pricing is not enough. First, all progressions have an end. Once users are at the end of progression, they will start accumulating currency. Second, most games feature  modes that are independent from the progression system, and reward currency. These grinding game modes allow users to accumulate currency without engaging with the progression system – in this case most of the time they are converting time (the time to get the energy required to play) for currency.

First, this progression system which provides the standard to balance in-game currency is also the main reason balances can get out of hand. Having a progression also means there is an end point. You might have reached the final mission. Or maybe you have maxed out your character and can no longer improve it. Whatever it might be, once users can continue playing (and accumulating resources) after they’ve reached the end point, they are bound to start accumulating soft currency. And while that might not be a problem at first, that compromises any future content release – where users will instantly have enough to buy/upgrade/craft the new content. This end point can be very theoretical. You can have the end-goal so far it will take years for a non-payer to achieve it. But the end point will always be there.

Even if your end-point is very far away, you should still try to keep balances in check. Your most engaged players are the ones who will reach the end point. That very small percentage of your installs are the users you want to be catering to. In addition, you will have a higher concentration of customers reaching those end points. To keep your game healthy, you want the balances of your customers to be in check – those are the users with the highest propensity to spend. Even if we’re talking about soft currency, scarcity is always an opportunity to monetize.

So, the best way – from a gameplay tuning point of view – is to ensure your prices are high enough to sustain months of continuous play. I do find there are many shortcomings to the monetization strategy in Clash Royale. But one thing that is very well done is the increase in gold cost to upgrade your cards. If you think you earn x gold per victory in Clash Royale – and approximately y gold via donations and other contingencies – then you can start to calculate how many days of play you need to max out a card (for the sake of the argument I’m going to assume here the bottleneck to level up a card will be gold). It’s going to happen, but it’s going to take a long time before gold becomes effectively useless. Also, because of the costs to upgrade cards and the way users accumulate cards, you’ll most probably have one last great bottleneck before maxing out your deck.

In Clash Royale a lot of wins are required to accumulate the necessary gold to max out a card


The second limitation has to do with “grinding” game modes. These modes have no end-point, and users can continuously play them without needing to spend currency. When there is replayability in your game – or a game mode users can grind – there is an “out”. Users can trade time for soft currency without progressing. Having grinding modes in your game can be a good thing – you can tune your game so users need to grind x missions in addition to following the main progression path (or alternatively do an IAP instead of grinding). The idea here is clearly not to remove that crucial game mode. The main point is that once your game has a game mode that can be replayed an infinite amount of times for no cost, you are exposed to an imbalance of currency progression will not help you contain.

Prison Break is an example of grind game mode in Sniper 3D Assassin


In-game tuning is clearly a crucial component of keeping your soft currency balances in check. I cannot stress that enough here. But 1) there is an end to every progression system and 2) most games feature game modes where users can grind. Because of that your game is not a controlled and closed system. Some games have introduced fun, immediately gratifying and rewarding features that provide infinite currency sink that can further help you keep balances low.


Keeping balances in check via evergreen sinks

There is another interesting type of features that you can come across in various games. The main goal of those features is to act as a “balance control” feature by providing a currency sink: users spend to engage with it. These features are totally independent from the gameplay loop and its progression. What’s more, users can continuously engage with it without restrictions. That’s what I mean by evergreen. Having an evergreen sink in your game is a way to ensure users always have something to spend on, and as a result that balances never get too out of hand.

Very consistently, those sinks are some variant of casino game users can engage with both very quickly and repeatedly. They are effectively sinks because very often users will spend currency and walk away with nothing – or with something very nominal. The slot model is one of the most widespread models. Most probably because it appeals to users’ sense of gambling. Not only does it act as an effective sink, it’s also something that can be immediately understood by a vast portion of the userbase and requires little commitment (either in terms of cognitive load, time, or gameplay).

There are multiple variants of these gambling evergreen features. Some provide you with an opportunity to receive various rewards. For example, you spend gold in the hopes of winning more gold, or hard currency.

The slot mini-game in Cooking Fever provides users with a chance to win gold or gems


Some like WSOP are a straight up slot machine – where users spend coins to receive coins. From a tuning point of view this is the ideal model of gold sink. For every coin spent in the slot machine, users will receive a fraction of a coin (that’s why you need to think about probabilities at the population level, not in terms of individual occurrences). Although this might be a more lackluster implementation in terms of content, the main strength of this feature has to do with timing. It is specifically highlighted when waiting for a table to be ready. Stated differently, the strength of this feature in WSOP lies more in it appearing at the right moment – rather than featuring a compelling value proposition.

In WSOP you can spend coins in the slot machine while waiting for the table to fill

My personal favorite is the implementation in Tri Peaks Solitaire: the Treasure Shrine. It’s basically an implementation of Plinko (for fans of “The Price is Right”).

The evergreen sink in Tri Peaks Solitaire


The way it works is simple. Users spend 2500 coins for a drop, and always walk away with something. The jackpot is 1,000,000 coins (over $100 value). Anything else, the user will walk away with less coins. The worst prize is 2000 coins (so that’s 500 coins less in the user’s balance). Users can also walk away with boosters, or a Wild Card (which can only be purchased as an IAP). If the user gets any of those s/he walks away with 2500 coins less.

What I find the most interesting here has to do with the way Tri Peaks structures the payoffs. The game is very gratifying – users always walk away with something (and less coins). More importantly, the game offers compelling rewards. The Treasure Shrine is one of the only opportunities nonpayers have to get some key boosters. By providing compelling rewards – at low probabilities – Tri Peaks provides an evergreen sink that is compelling because of its rewards (where WSOP is mostly compelling because of its placement).

There are multiple potential implementations for an evergreen sink, and the one discussed here are simply illustrations of a general concept. Regardless of the specifics of its implementation, having a currency sink that is a) independent from the game’s core loop and progression and that b) users can always engage provides an additional control regulation mechanism to keep balances in check. Because it is independent from the game’s progression – and most of the time from the game loop itself – it helps address some structural limitations of progression-based tuning.

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