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Kleros courts are organized in a hierarchical tree structure, allowing disputes to be handled by jurors with appropriate expertise while maintaining a clear appeals path.
The hierarchical model is the same in both protocol versions. V1 uses the term subcourts and its court tree runs on Ethereum Mainnet; V2 uses the term courts and runs on Arbitrum. The tree, parameters, and examples below reflect V2. Curation for the Curate products also runs on Gnosis Chain using V1 courts. Governance proposal KIP-87 created a new Gnosis Chain Curation Court with hidden voting, which went live in June 2026.

Court Structure

The court tree forms an arborescence with the General Court as the current root. New courts can be added by governance as Kleros is adopted for additional dispute types.
This diagram reflects the court tree from the Kleros yellow paper (Figure 5). The live court tree on v2.kleros.builders may differ as courts are added or modified through governance.

Court Types

The Root Court (ID: 1)The General Court currently serves as the root of the entire court system. It handles appeals from all specialized courts and has the broadest juror pool because staking in any specialized court automatically stakes you in all parent courts up to the General Court.Every juror in the Kleros system is, by definition, a General Court juror.

Court Parameters

Each court has parameters that define how it operates. These are set during court creation and can be changed by governance so always check v2.kleros.builders for current live values.
Court parameters are adjusted through governance and may differ from any static source. Always verify current values at v2.kleros.builders.

Mainnet Court Parameters (Arbitrum One)

The following table shows the production court configuration as deployed. Values are governance-controlled and may have changed since this was written - always cross-check with v2.kleros.builders.
Courts 29 and 32 (Argentina Consumer Protection courts) use DisputeKitGated and require specific SBT eligibility tokens. See Deployment Addresses V2 for SBT contract addresses.

Testnet Parameters (Arbitrum Sepolia)

Testnet court parameters are deliberately different from mainnet to allow faster testing: Do not use testnet parameter values to estimate mainnet costs or draw probabilities.

Understanding Alpha

The alpha parameter determines how much of your stake is locked when drawn as a juror:
With minStake = 2,300 PNK and alpha = 10000 (100%)Your locked amount per vote = 2,300 PNKIf alpha were 5000 (50%), your locked amount would be 1,150 PNK per vote. The alpha parameter effectively sets the economic risk of participating as a juror higher alpha means more PNK at stake per vote.

Time Periods

Each dispute progresses through four key periods, with durations defined per court:
  1. Evidence Period: Time for parties to submit evidence
  2. Commit Period: Time for jurors to commit votes (when hiddenVotes = true)
  3. Vote / Reveal Period: Time for voting or revealing committed votes
  4. Appeal Period: Time to fund appeals

Automatic Parent Staking

Critical Concept: When you stake in a specialized court, you are automatically staked in all parent courts up to the General Court. What this means in practice:
  • Staking in the Solidity court = also eligible for Blockchain Technical and General Court cases
  • Staking in Curation (Medium) = also eligible for Curation and General Court cases
  • The General Court includes every juror in the entire system
This ensures sufficient juror availability at each level and maintains a proper appeals path where parent courts always have a broader jury pool than their children.

Multi-Court Staking

You can stake in multiple courts, but there are important constraints:

Court Limit

There is a MAX_STAKE_PATHS limit on how many courts a single juror can stake in simultaneously. This exists for gas efficiency many sortition operations scale linearly with the number of staked courts.
Verify the current MAX_STAKE_PATHS value on-chain or in the Sortition Module contract. If you attempt to stake in more courts than allowed, the transaction will revert with CannotStakeInMoreCourts.

Choosing Courts

Consider these factors when selecting courts:
  1. Your Expertise: Match courts to your knowledge areas, read each court’s policy before staking
  2. Minimum Stake: Ensure you meet the court’s minStake requirement (check live values)
  3. Activity Level: More active courts = more earning opportunities
  4. Policy Alignment: Understand and agree with court rules before committing PNK

Court Policies

Each court has a policy document that defines: Policies are managed through the PolicyRegistry contract and can be updated by governance. Child courts inherit policies from their parent courts so General Court policies apply everywhere.
Critical for Jurors: Always read the court policy before staking or voting. Failing to follow court policies may result in incoherent votes and lost PNK.

Explore Court Policies

Visit Kleros Court, click on “Courts” and review the policy for any court that interests you.

Court Transparency Features

The V2 interface provides enhanced transparency for each court:
  • Top Jurors Staked: See who has the largest stakes in each court
  • Latest Stakes: Monitor real-time staking activity
  • Court Statistics: View dispute history and resolution rates
  • Court Parameters: All parameters are viewable on-chain and in the Court UI

What’s Next?

Appeals

Learn how cases escalate through the hierarchy

How It Works

Understand the full dispute resolution process

Staking Guide

Step-by-step guide to staking in courts