Stake Validator Pattern

This pattern allows for delegating some computations to a given staking script. The primary application for this is the so-called “withdraw zero trick,” which is most effective for validators that need to go over multiple inputs.

The Pattern

With a minimal spending logic (which is executed for each UTxO), and an arbitrary withdrawal logic (which is executed only once), a much more optimized script can be implemented.

The spending validator essentially says: As long as there is a reward withdrawal of the given script in transaction, this UTxO can be spent.

When It Helps

Useful for:

• Validators that need to go over multiple inputs
• Batch operations where per-input logic can be minimal
• Reducing execution costs for multi-input transactions

Not suitable for:

• Single input transactions
• Cases where each input needs unique validation
• When per-input state transitions are complex

Implementation

The scalus-design-patterns package provides helper functions and examples of use.

Additional Resources

• Anastasia Labs: Stake Validator Pattern  - Original pattern documentation
• Scalus Design Patterns  - Implementation and tests