In Move, especially on Sui, structuring and managing error codes is crucial for scalable and secure smart contract development.

Key practices:

Group error codes logically: Use constants in a shared errors.move module. Example: E_UNAUTHORIZED, E_INVALID_INPUT.

Use consistent ranges: Allocate code ranges per module (e.g. 0–99 for auth, 100–199 for NFTs) to prevent conflicts.

Fail early: Validate inputs at the start of functions and abort immediately to save gas and reduce state changes.

Promote reuse: Import a shared error module rather than repeating code.

Debug effectively: Use Sui CLI or SDK to catch error codes and map them back to your constants.

Test clearly: Use assert_abort_code in tests to check expected failures and validate code paths.

This approach improves maintainability, reduces gas, and helps surface clear errors in dApps and tooling.