Validation library offering a declarative API for writing clear, maintainable validation code. Handles complex business logic, supports custom constraints, is highly extendable, and integrates with popular frameworks.
Get started by reading the documentation
Akkurate is a validation library taking advantage of the expressive power of Kotlin. No need
for 30+ annotations or complicated custom constraints; write your validation code in Kotlin with a beautiful declarative
API.
Designed from scratch to handle complex business logic, its role is to help you write qualitative and maintainable validation code.
[!WARNING] Akkurate is under development and, despite being heavily tested, its API isn't yet stabilized; breaking changes might happen on minor releases. However, we will always provide migration guides.
Report any issue or bug in the GitHub repository.
Here's an example showcasing how you can constrain a book and its list of authors.
Notice how each constraint applied to a property can be read like a sentence. This code:
title.isNotEmpty() otherwise { "Missing title" }
can be read:
Check if 'title' is not empty otherwise write "Missing title".
// Define your classes
data class Book(
val title: String,
val releaseDate: LocalDateTime,
val authors: List<Author>,
)
data class Author(val firstName: String, val lastName: String)
// Write your validation rules
val validateBook = Validator<Book> {
// First the property, then the constraint, finally the message.
title.isNotEmpty() otherwise { "Missing title" }
releaseDate.isInPast() otherwise { "Release date must be in past" }
authors.hasSizeBetween(1..10) otherwise { "Wrong author count" }
authors.each { // Apply constraints to each author
(firstName and lastName) {
// Apply the same constraint to both properties
isNotEmpty() otherwise { "Missing name" }
}
}
}
// Validate your data
when (val result = validateBook(someBook)) {
is Success -> println("Success: ${result.value}")
is Failure -> {
val list = result.violations
.joinToString("\n") { "${it.path}: ${it.message}" }
println("Failures:\n$list")
}
}
Beautiful DSL and API
Write crystal clear validation code and keep it DRY. Use loops and conditions when
needed; forget about annotation hell.
Bundled with all the essential constraints
Write custom constraints for your business logic and nothing more. The rest? It's on us!
Easily and highly extendable
No need to write verbose code to create custom constraints, within Akkurate they're as simple as a lambda with
parameters.
Contextual and asynchronous
Query sync/async data sources whenever you need to, like a database, or a REST API. Everything can happen inside
validation.
Integrated with your favorite tools
Validate your data within any popular framework, we take care of the integrations for you.
Code once, deploy everywhere
Take advantage of Kotlin Multiplatform; write your validation code once, use it both for front-end and back-end
usages.
Testable out of the box
Finding how to test your validation code shouldn't be one of your tasks. You will find all the tools you need to write
good tests.
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