OpenAPITools/openapi-generator · error · IllegalArgumentException

The input ({inputFramework}) contains Invalid .NET framework

Error message

The input ({inputFramework}) contains Invalid .NET framework version: {framework}. List of supported versions: {versions}

What it means

Error "The input ({inputFramework}) contains Invalid .NET framework version: {framework}. List of supported versions: {versions}" thrown in OpenAPITools/openapi-generator.

Source

Thrown at modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/CSharpClientCodegen.java:830

            frameworks = new String[]{inputFramework};
        }

        for (String framework : frameworks) {
            boolean strategyMatched = false;
            for (FrameworkStrategy frameworkStrategy : frameworkStrategies) {
                if (framework.equals(frameworkStrategy.name)) {
                    strategies.add(frameworkStrategy);
                    strategyMatched = true;
                }

                if (frameworkStrategy != FrameworkStrategy.NETSTANDARD_2_0 && RESTSHARP.equals(library)) {
                    LOGGER.warn("If using built-in templates, RestSharp only supports netstandard 2.0 or later.");
                }
            }

            if (!strategyMatched) {
                // throws exception if the input targetFramework is invalid
                throw new IllegalArgumentException("The input (" + inputFramework + ") contains Invalid .NET framework version: " +
                        framework + ". List of supported versions: " +
                        frameworkStrategies.stream()
                                .map(p -> p.name)
                                .collect(Collectors.joining(", ")));
            }
        }

        configureAdditionalPropertiesForFrameworks(additionalProperties, strategies);
        setTargetFrameworkNuget(strategies);
        setTargetFramework(strategies);
        setTestTargetFramework(strategies);

        setSupportsAsync(Boolean.TRUE);
        setNetStandard(strategies.stream().anyMatch(p -> Boolean.TRUE.equals(p.isNetStandard)));

        if (!netStandard) {
            setNetCoreProjectFileFlag(true);

View on GitHub (pinned to fcec517be3)

Solutions

1. Set targetFramework to one of the supported .NET framework versions listed in the message.

When it happens

Trigger: Thrown when the target framework string given to the C# client generator contains a .NET framework version that is not supported. Use one of the listed supported versions.

Common situations: See trigger scenarios.

AI-assisted analysis of OpenAPITools/openapi-generator@fcec517be3 (2026-08-22). Data as JSON: /api/errors/714a7a4970fa686a. Report an issue: GitHub.