Arx - NameGuard

Nameguard is a fast, language-agnostic validation engine for checking invalid, reserved, or disallowed names using curated datasets and structured rules

• Typical use cases include:
  • subdomain and DNS label checks
  • locale and timezone validation
  • reserved keyword enforcement

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Key Features

• Extremely fast lookups

  • O(1) validation using compile-time generated data
  • zero heap allocations during validation

• Data-driven

  • curated datasets for:
    • locales
    • timezones
    • reserved subdomains / identifiers
  • data is compiled into the binary (no runtime parsing)

• Pattern-aware validation

  • structural rules (DNS labels, identifiers)
  • prefix / suffix constraints
  • regex only when unavoidable

• Language-agnostic core

  • Rust core with a stable C ABI
  • bindings currently available for TypeScript
  • designed for future ports (Go, Ruby, Python, etc.)

• Safe by default

  • explicit validation results
  • no panics, no exceptions across FFI boundaries

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Performance

• Nameguard is optimized for hot paths:

  • perfect hash sets (PHF)
  • branch-predictable logic
  • no heap allocations during validation
  • no runtime data loading

• This makes it suitable for:

  • API gateways
  • auth systems
  • domain / username registration
  • security-sensitive validation layers