Design Rationale Reference

This reference document catalogs the key design decisions and technical constraints that shaped the ERC-7730 standard.

Core Design Principles

Human Readability Considerations

The standard prioritizes human readability through several specific design choices:

Developer-Friendly Specification Format

• The specification uses a syntax and structure designed for direct readability by developers
• Implementation patterns are documented alongside the specification to provide context

JSON as Data Format

• JSON was selected as the primary data interchange format due to:
  • Widespread familiarity among developers
  • Extensive library support across programming languages
  • Native parsing capabilities in most development environments
  • Human-readable structure for debugging and implementation

Adoption Incentives

• The standard incorporates incentives for metadata file creation:
  • Promises of wide wallet support for compliant implementations
  • Improved user experience as a direct result of implementation effort

Hardware Wallet Design Constraints

Technical limitations of hardware wallets significantly influenced the specification:

Display Limitations

Field Structure Decisions

Flattened Field Structure

• Complex UI constructs like layouts and grouping were made optional
• Primary data fields prioritized for constrained displays
• Progressive enhancement pattern for more capable wallets

Message Structure Flattening

• Complex nested structures are discouraged
• Recommended approach converts nested objects to flattened field lists
• Improves display compatibility across hardware wallet types

Recursive Processing Limitations

• Formatters requiring recursive processing (e.g., calldata) have documented limitations
• Alternative patterns provided for hardware wallet implementations
• Graceful degradation paths for complex data structures