Introduction

Acanthis validates data at runtime. Define a schema, pass it an input, and get a typed value or issues that describe what failed.

import 'package:acanthis/acanthis.dart';

void main() {
  final email = string().trim().email();

  final String address = email.parse(' ada@example.com ');
  print(address); // ada@example.com
  print(email.validate('invalid')); // false
}

Schemas compose: use the same email schema in an object, a list, or a nullable field. Fluent methods return new schemas, so adding a check leaves the original reusable.

Installation

These docs describe the V2 API in this repository. Use Dart 3.13 or later, or a Flutter SDK that includes a compatible Dart version. When using a published package, check that its version exposes this API.

Dart

dart pub add acanthis

Flutter

flutter pub add acanthis

All public APIs are available from one import:

import 'package:acanthis/acanthis.dart';

Choose your next step

You want to…	Read
Define and parse your first object	Quick start
Find a type or a check	Schema reference
Show useful errors	Results and issues
Validate a form as it changes	Live validation
Share a JSON contract	JSON Schema
Upgrade an existing project	Migrating to V2

Acanthis does not require code generation. Objects produce maps; use a class schema when you want a Dart class as output.