Appeals

How to challenge rulings and escalate disputes through the court system

Appeals

The appeals system is a core feature of Kleros Court that ensures fairness and allows for error correction. Any party—or even third parties—can challenge a ruling by funding an appeal.

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How Appeals Work

1. Initial Ruling

   After jurors vote, a preliminary ruling is reached based on majority decision. This ruling enters the Appeal Period.

2. Appeal Funding

   During the appeal period, anyone can fund an appeal:

   • Challenger: Funds to overturn the ruling (2× appeal cost)
   • Winner: Funds to defend the ruling (1× appeal cost)
3. Counter-Funding

   If one side funds, the other side has the opportunity to counter-fund. If only one side funds fully, that side wins by default.

4. New Round

   If both sides fund, a new round begins with more jurors. The process repeats until appeals are exhausted or unfunded.

5. Final Ruling

   When no more appeals are funded (or the appeal period expires), the current ruling becomes final and is executed.

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Appeal Funding Requirements

The appeal system uses asymmetric funding to create proper incentives:

Side	Funding Required	Rationale
Challenging Side	2× appeal cost	Higher barrier discourages frivolous appeals
Winning Side	1× appeal cost	Lower cost to defend legitimate rulings

Calculating Appeal Cost

appealCost = feeForJuror × ((currentJurors × 2) + 1)

Appeal Cost Example

Scenario: Current round has 3 jurors at 0.05 ETH each.

Next round will have: (3 × 2) + 1 = 7 jurors

Appeal costs:

• Challenger: 0.05 ETH × 7 × 2 = 0.70 ETH
• Winner: 0.05 ETH × 7 × 1 = 0.35 ETH

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Funding Deadlines

Timing is critical for appeals. Miss the deadline and your opportunity is lost.

Party	Deadline
Challenger	First half of appeal period only
Winner	Entire appeal period

This asymmetry creates urgency for challengers while giving winners adequate time to respond.

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Juror Progression

With each appeal round, the number of jurors increases:

Round 1:  3 jurors
Round 2:  7 jurors    (3×2 + 1)
Round 3:  15 jurors   (7×2 + 1)
Round 4:  31 jurors   (15×2 + 1)
Round 5:  63 jurors   (31×2 + 1)
...

This exponential growth ensures that:

• Important cases receive thorough review
• The cost of repeated appeals increases substantially
• Eventually, a large enough jury reaches a stable consensus

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Court Jumps

When the number of jurors exceeds a threshold, the dispute “jumps” to a parent court:

How Court Jumps Work

1. Threshold Reached

   The dispute requires more jurors than the jurorsForCourtJump parameter (e.g., 511 jurors).

2. Escalation

   The dispute automatically moves to the parent court in the hierarchy.

3. New Parameters

   The dispute adopts the parent court’s parameters and juror pool.

4. Continued Resolution

   Jurors from the broader parent court now handle the case.

V2 Enhancements

Kleros V2 introduces significant improvements to court jumps:

Dispute Kit Jumps

If a parent court doesn’t support the current dispute kit, the dispute can switch to a compatible kit—including complex question types.

Dynamic Juror Adjustment

Juror numbers adjust dynamically based on the new court’s parameters and dispute kit requirements.

These jumps ensure that complex or contentious cases receive appropriate handling by a broader, less specialized jury.

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Appeal Rewards

Successfully funding appeals can be profitable:

If Your Side Wins

When you fund the winning side of an appeal:

• Your funding is returned
• You receive a portion of the losing side’s funding as profit
• Rewards are proportional to your contribution

If Your Side Loses

• Your funding is forfeited
• It’s distributed to the winning side’s funders

Appeal funding is a form of crowdfunding justice. Multiple contributors can fund a side together, sharing in the rewards or losses proportionally.

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Strategic Considerations

For Disputants

• Evaluate Strength: Only appeal if you have strong evidence the ruling was wrong
• Consider Costs: Each round is more expensive than the last
• Time Your Funding: Challengers must act in the first half of the appeal period

For Third-Party Funders

• Review Evidence: Study the case before funding either side
• Assess Probability: Consider how likely the ruling is to change
• Diversify Risk: Fund multiple appeals to spread risk

For Jurors

• Expect Appeals: Large-stake disputes often get appealed
• Court Jumps: You may be drawn for cases that jumped from sub-courts
• Increased Complexity: Appealed cases are often more contentious

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Appeal Flow Diagram

┌─────────────────────────────────────────────────────────────┐
│                     INITIAL RULING                          │
│                    (3 jurors vote)                          │
└─────────────────────────┬───────────────────────────────────┘
                          │
                          ▼
┌─────────────────────────────────────────────────────────────┐
│                     APPEAL PERIOD                           │
│   Challenger funds (2×) ◄──────► Winner funds (1×)          │
└─────────────────────────┬───────────────────────────────────┘
                          │
            ┌─────────────┼─────────────┐
            │             │             │
            ▼             ▼             ▼
     ┌──────────┐  ┌──────────┐  ┌──────────┐
     │  Both    │  │  Only    │  │ Neither  │
     │  Fund    │  │ One Funds│  │  Funds   │
     └────┬─────┘  └────┬─────┘  └────┬─────┘
          │             │             │
          ▼             ▼             ▼
     ┌──────────┐  ┌──────────┐  ┌──────────┐
     │  NEW     │  │ Funded   │  │ Current  │
     │  ROUND   │  │ Side     │  │ Ruling   │
     │(7 jurors)│  │  Wins    │  │ Executed │
     └──────────┘  └──────────┘  └──────────┘

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What’s Next?

Court Hierarchy

Understand how courts are organized

How It Works

Full dispute resolution process

Fund an Appeal

Browse active cases with open appeals

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Quick Links

Appeal Calculator

Estimate appeal costs for active disputes

Active Appeals

View disputes currently in appeal period