Thanks to the contribution by "ircecho" (<a href="https://github.com/OpenAPITools/openapi-generator/pull/2894" rel="nofollow">https://github.com/OpenAPITools/openapi-generator/pull/2894</a>), the Dart API client generator in the OpenAPI Generator project now supports Dart 2.3 which was released recently. Here are a few steps to generate Dart API client given an OpenAPI specification file:<p>1. Download the Java JAR (<a href="https://oss.sonatype.org/content/repositories/snapshots/org/openapitools/openapi-generator-cli/4.0.1-SNAPSHOT/openapi-generator-cli-4.0.1-20190515.161655-6.jar" rel="nofollow">https://oss.sonatype.org/content/repositories/snapshots/org/...</a>)<p>2. Rename the JAR as "openapi-generator-cli.jar"<p>3. Run the following command to generate a Dart API client for the Petstore API (<a href="https://raw.githubusercontent.com/OpenAPITools/openapi-generator/master/modules/openapi-generator/src/test/resources/2_0/petstore.yaml" rel="nofollow">https://raw.githubusercontent.com/OpenAPITools/openapi-gener...</a>):<p>Mac/Linux:<p>- java -jar openapi-generator-cli.jar generate -g dart -i <a href="https://raw.githubusercontent.com/OpenAPITools/openapi-generator/master/modules/openapi-generator/src/test/resources/2_0/petstore.yaml" rel="nofollow">https://raw.githubusercontent.com/OpenAPITools/openapi-gener...</a> -o /var/tmp/dart-api-client/<p>Windows:<p>- java -jar openapi-generator-cli.jar generate -g dart -i <a href="https://raw.githubusercontent.com/OpenAPITools/openapi-generator/master/modules/openapi-generator/src/test/resources/2_0/petstore.yaml" rel="nofollow">https://raw.githubusercontent.com/OpenAPITools/openapi-gener...</a> -o C:\tmp\dart-api-client<p>Please give it a try and let us know if you've any feedback.