Doges on Trial: Kleros’ Launch on Mainnet

Testing the Cryptoeconomics of Decentralized Justice…

Federico Ast
Published in
7 min readJul 24, 2018


We are happy to announce that Kleros will launch on the Ethereum mainnet on Tuesday July 31st!

Kleros proposes a completely innovative way of doing dispute resolution, a method based on game theory to generate economic incentives for jurors to rule cases honestly and on blockchain to guarantee security in the process (to learn more, read our white paper).

Doges on Trial, our first cryptoeconomic experiment on the Ethereum mainnet, is based on Kleros’ curated list application, a key area of research within the decentralized ecosystem.

Curated Lists: Organizing Information in Decentralized Communities

Traditional Internet companies organize information with centralized rules and moderators. Yelp!, eBay and Google all have rules to determine what restaurants, products and websites should be accepted in their listings and in which positions they should be presented to consumers. Of course, they leverage user input (e.g., reviews, reports about violations of terms and conditions, etc.), but the company always has the final word.

How can decentralized versions of Yelp!, eBay and Google define which restaurants, products and websites to accept in a decentralized way?

Cryptoeconomic mechanisms can provide an answer to this question under the form of token curated lists. This is how they work:

  1. User A submits Item X he wants to add to the list (e.g., a restaurant to be added to the list of best restaurants in the area). The user needs to deposit some funds in order to make the submission.
  2. Item X remains visible for other users during a “challenge period”. During this time, the item can be challenged by users who think it shouldn’t be allowed in the list.
  3. User B, who thinks that Item X violates the rules, challenges User A’s submission. In order to challenge the item, User B also needs to deposit some funds.
  4. A dispute arises between User A (who claims that Item X should be allowed into the list) and User B (who claims Item X shouldn’t be allowed).

Kleros can be used as arbitration protocol for this dispute. A panel of jurors, selected and incentivized by Kleros, will analyze the submission and decide whether it complies or not with the rules. If User A wins, Item X will be accepted into the list. If User B wins, Item X will not be accepted.

Doges on Trial is our first cryptoeconomic experiment to test how Kleros can arbitrate disputes arising from a user curated list of Doge images.

“Thanks for participating in our cryptoeconomic experiment! Woof!”

A List of Doges

At Kleros, we love the Doge (who doesn’t, right?) and we want to use crowdsourcing to create a large list of Doge images. So we will pay people to contribute with Doges to the list. However, we fear malicious users might try to submit images different than Doges or that they will just submit the same image many times.

We want to use the wisdom of the crowd to accomplish the following goals:

  1. Create the largest possible Doge images list.
  2. Make sure that only Doge images make it into the list.
  3. Make sure that no duplicate Doge images enter the list.

There are three types of users in this experiment: submitters, prosecutors and jurors.

(Users don’t need to “login” as submitter, prosecutor or juror. They just play these different roles by taking different actions in the platform.)


The role of submitters is to submit images into the list. For each submission, they will need to make a deposit in ETH. After the submission is made, funds stay locked during a “challenge period”.

Two things may happen during this period:

  1. Nobody challenges the submission, in which case the image enters the list and the submitter is refunded his deposit.
  2. A prosecutor challenges the submission, in which case the image goes to dispute resolution.
Uploader for submitting images.

Submitters are rewarded in two ways:

By submitting valid Doge images. At the end of the experiment, we will make a list of the submitters who posted unique Doge pictures. We will split 1,000,000 Doge Coins between all of them.

By conducting successful attacks on the system. If a submitter gets a cat accepted into the Doge list, it will receive 2 ETH and a Cryptokitty (this reward is limited to the first 10 cats accepted). For an attack to be considered successful, the cat submission has to either fail to be challenged by prosecutors s challenged and wins the trial (and is not rechallenged)


In traditional justice systems, prosecutors are in charge of starting legal proceedings against suspects. They “flag” suspects of having broken some community rule and then the case goes to trial.

In Doges on Trial, prosecutors will flag submissions they think do not comply with the rules (being a unique Doge image). Each time they challenge a submission, prosecutors need to deposit ETH.

Flagged submissions go to trial: should the image be allowed or not into the list? The decision will be made by a Kleros jury.

The home page of our Doges on Trial pilot. (Images will differ)
If you see an image you don’t think is a doge. Send it to Trial!
After the dispute is ruled, the losing party can appeal the jury decision and have it ruled again.


Jurors decide whether a flagged image is a Doge or not. For each case it solves, a juror will receive a compensation in ETH that comes from the deposit of the losing party. In order to be randomly chosen to solve disputes, jurors need to deposit the PNK token (the token is important for Kleros’ incentive system to work correctly. To learn why, read this post).

The final outcome of a case (Appeal still possible).

What We Want to Test?

Kleros is based on the idea that economic incentives will make jurors vote honestly for the “true” answer. Our hypothesis is that “truth” will work as a Schelling Point for jurors voting independently under an incentive system such as the one in this experiment (to learn more about how the system works, read the white paper).

Give these incentives, we expect that users will self-organize in order to create a large list of Doges and only Doges. Economic incentives will make users submit images, challenge them and participate in dispute resolution.

Our goal is to understand user behavior and to test the system defenses against a number of hostile actions such as bribes and p+epsilon attacks. We will measure user willingness to appeal dishonest outcomes (particularly, in the presence of attacks), varying the budget and nature of attacks and observing effects in more or less ambiguous cases (e.g., cases where someone submits a photoshopped dog-cat hybrid).

The Doges on Trial experiment is made on the mainnet as this is key to provide real economic incentives to participants which could not be provided on the testnet. It is important to bear in mind that this is a simplified version of Kleros with a number of key features still not implemented such as secret voting, governance, multiple subcourts and the possibility to split appeal fees (to learn more about our development roadmap, read this).

Moreover, in order to understand attacker behavior, economic incentives for malicious actors are artificially inflated (e.g., an attacker would get a disproportionately large reward for successfully attacking the system by having a cat accepted into the list). The intention is to put Kleros under a stress test, with conditions even harsher than what they would be in normal situations.

As in any early stage technology, our goal here is not to present a “perfect version” of Kleros, but to learn as much as possible from attacker behavior in order to improve the mechanism design for future versions. Doges on Trial will allow us to test our cryptoeconomic system under a relatively benign failure mode (e.g., a successful attack would mean that users will see cats in a Doge list instead of losing real money in a dispute) and in a fun way for testers.

Doges on Trial may look like a “silly” experiment. But information on user behavior collected during the tests will open the door to many fascinating Kleros applications in the realm of curated lists, including content moderation in decentralized social media and product listing in e-commerce platforms among many others.

Want to Participate?

The experiment will launch on Tuesday July 31th. You have one week to make sure you have everything ready to participate. You will need:

  1. A Web3 browser enabled (e.g. MetaMask)
  2. ETH in your Web3 browser.
  3. PNK (Kleros’ ERC20 token) in your browser.

If you need help with the setup, you can ask for assistance in our Telegram group.

After many months of hard work by the team, we are thrilled about Kleros’ upcoming launch on the main net!

Join us in building the future of justice!

Join Kleros!

Join the community chat on Telegram.

Visit our website.

Follow us on Twitter.

Join our Slack for developer conversations.

Contribute on Github.



Federico Ast
Editor for

Ph.D. Blockchain & Legaltech Entrepreneur. Singularity University Alumnus. Founder at Kleros. Building the Future of Law. @federicoast /