Simple smart contract / DApp ideas that you would like to see



I would like to collect some simple smart contract ideas (by simple I mean not Uber or Twitter :rofl:) in this thread that you would like to see and maybe someone will build it or will share an example like @bobert did with the Naive Lottery Contract.

It would be nice if you could provide a small use case as well, but this is not needed. Example:

The Tip-Contract
Sending some amount to an address and it will be split (equally or by some sort of distribution key) to other addresses that are locked into the contract.

If the tip is very small it should keep the balance in the contract and distribute it later.

Use Case
Let’s say something like the Cardano Effect has an address and if you send a tip to it, the contract automatically splits the tip to @philpa , @rickymac and Sebastien.

This chart looks accurate. It might piss you off. We need to change this in 2019

I imagine something where you can store crypto on cardano blockchain .For example you could create an bitcoin wallet on this dap, the secret key is stored on cardano blockchain and then you can spend btc (for example)with your cardano dap.


I also like the idea of infiniverse eos dap.Something like this but dfferent in the way that if you buy something it belongs to the buyer and not only for one year.There could be a small maintainance fee.


The Testament
You could lock an amount into a contract and need to “ping” from time to time (for example every 3 months) to keep the amount locked. This works basically like a dead-man’s button. Once you stop pinging for a defined period the amount will be send to an address.

Use Case
If something bad happens to you and you are not able to ping for example one year then your funds will be send to your wifes / childs / friends address.


The Subscription
You lock up P * A in a contract. The counterparty is able to withdraw A amount, P times at predefined intervals. You can cancel and get back remainder (less a penalty - optional)

Use Case
Repeat payments for service or content. Nice because vendor has known financial commitment providing service is good. Also with penalty, vendor can offer graduating pricing based on duration of commitment.

Subscribe for access to game for 52 weeks. 10 ADA per week. Deposit 520 ADA. Vendor takes 10 ADA per week as they deliver the service. I cancel after 22 weeks, get 250 back, vendor gets 50.


This is a great idea for a thread. When I get more time to write some more examples I’ll check back here and see if there’s any good ideas to show off a new concept or two and kill two birds with one stone.


Hi @adatainment
Something I think has a great use case on a block chain - because it solves a problem - is coupons. I have been laughed at before for this :grin:

Coupons are a good use case for a couple reasons:

  1. A coupon is a smart contract already - if you purchase X product by Y date, we give you $Z discount.
  2. Coupons are still on paper, where as most payments people do in the USA at retail outlets are electronic credit or debit.
  3. The retail outlet issuing coupons can issue a limited number of coupon tokens on the blockchain.
  4. The retail outlet can better track how many coupons have been used and how many are still out there.
  5. Often when my wife and I are at the store (Bed Bath and Beyond, Groceries) she says “Oh I left my coupons at home” which would not be a problem on the cell phone.
  6. Shoppers can trade coupons from cell phone to cell phone. Yay!

Any other inputs on the coupons thingy?



I like the coupon idea. I think it is approaching slightly more complex contract as you could potentially need to verify a few things like (1) previous coupon usage (2) valid combination of coupons (3) time period of coupon validity and perhaps introduce new like (4) Limit by X amount of coupons usage.


Example use case Amazon - real guarantee issue

I recently bought a product on Amazon. After more than a month of use, I no longer needed it and decided to put it on sale as a second-hand product. I contacted Amazon customer service to get more information about the guarantee of the product. Legally it still has 22 months guarantee. My question to the Amazon services was the following:
Me: What happens to the guarantee if the product changes ownership?
Amazon: “The guarantee is canceled, it is no longer valid”,

So, for the fact that a product changes ownership, it does not matter the status of the guarantee, automatically this is no longer valid.

This operation of change of owner could be transcribed through smart contracts. Amazon could check and verify the authentic owner and manage the guarantee.

In addition, thieves will have a hard time explaining that the purchase they made was legitimate when the determined entity verifies that this product has only had and has one owner.


Good inputs, thanks. My first 6 points already address your points (1) (3) and (4) but I don’t know what you mean by (2) valid combination of coupons. I thought I addressed that when purchasing X product.

Anyway, I thought of another point… my original points 1-6 now +7

  1. It will bring more women into the blockchain system without having to understand Ouroboros, NiPoPos, side chains, or consensus algorithms. But “Buy one get one free” heck yeah! :wink:


Again love the idea Coupons smart contract as yeah it does definitively bring other interests into blockchain :slightly_smiling_face:

No because none of those points track personal usage of a coupon so you do not know previous coupon usage and cant limit any given person x to scoop up everything etc. You would need an ID layer for that. But of course coupons does not have to behave like that either.

Not a problem right now but just thinking in the future if there where many different coupons from different companies and when combined on a specific product it could give it free or money back + product. So could be useful to have some rules on maximum possible discount combination etc. (Yes I admit I watched one episode of coupon hunters with my wife :P)

But again great idea Rick to bring coupons to the blockchain just trying to think to flesh it out more . But for sure as a simple contract accepting a single coupon X for given time Y on product Z (as you propose) it should be neat.


The Allowance Contract.
Feed a contract with an amount that can be distributed X each time unit Y to wallets Z(n) (for example weekly).

The More Advance Allowance Contract
Allow wallet owner to also issue tasks on sidechain with IELE and when wallet owner is satisfied with task completion unlocks distribution of amount X by time unit Y to wallets Z(n).

Why on blockchain instead of just good old money? Because it can be automated. Because you can set it off on your mobile and check in real time who in family has done what task. Because…because if it makes your kids do the chores its awesome.


It’s very good idea.


I also like the coupon idea. Because of the transactions fees, I don’t think I will be good for every coupon but for “high quality ones” like the “buy 10 pizzas and get one for free”-coupon it would be too cool. Same applies movie, theatre and musical tickets.

Like @Eystein_Hansen already wrote, it’s not a simple example and needs to be broken down into smaller once.


The Simple Ticket Store
Pay a certain amount to get a ticket. Amount of tickets are limited.

The Advanced Ticket Store
Like the simple ticket store, but this time there are ticket numbers (seats). Of course every seat can be sold once. It would be nice to have control over the amount of seats and the number when buying tickets.

Use Case
Ticket Store :face_with_raised_eyebrow:


You just helped me think of another detail… The transaction fees can be pre-paid by the sellers in the coupon smart contract, just like the sellers are the ones who pay to have their coupons listed in the newspaper. Many thanks to you and @Eystein_Hansen


I like this idea for Movie Tickets, Sports Tickets, Concert Tickets… any ticket that represents an exchange of value. The ticket can even have an expiration date (same as in a smart contract) based on the presentations given at Plutusfest.


I am glad you brought up this coupon suggestion Rick, I once managed a restaurant where I always had issues with coupons, I would like to see this coupon example, I look forward to it!


This leads me to another one:

Bonus Pizza
Every order increments a counter, when the counter hits 10 you will get a “Free Pizza”-Coupon.

Sounds pretty easy but wait - you can not simply just track the same addresses in the contract.

When ordering something the payment system will create a new payment address for this customer and monitors this address for the payment. Otherwise it’s not possible to assign payments to customers. (There are no messages in the transactions)

This means every time you order a pizza the payment address will be different. Therefore you need to assign some sort of other key to the customer in the contract, to implement this.

Use Case
Customer Loyalty


I like this idea because I always lose those stupid little punch cards. I get to like 7 of 10 holes punched and lose it. Store that stuff on a blockchain, app on the phone thingy.