sinatra-paramsinatra-param allows you to declare, validate, and transform endpoint parameters as you would in frameworks like ActiveModel or DataMapper.coercionparametersrubysinatravalidation
dry-schemadry-schema provides a DSL for defining schemas with keys and rules that should be applied to values. It supports coercion, input sanitization, custom types and localized error messages (with or without I18n gem). It's also used as the schema engine in dry-validation.coerciondata-validationdata-validatordry-rbrubyruby-gemschemaschema-validationtype-safety
dry-typesType system for Ruby supporting coercions, constraints and complex types like structs, value objects, enums etccoercionconstraintsdry-rbrubytypes
necromancerConversion from one object type to another with a bit of black magic.coercionconversionsrubyruby-gemtransformationtype-conversion
lotus-validationsValidations mixin for Ruby objects and support for Lotuscoercionrubyvalidationswhitelisting