OpenAPITools/openapi-generator · error · RuntimeException

Invalid project name {apiName}. May only contain alphanumeri

Error message

Invalid project name {apiName}. May only contain alphanumeric characters or underscore and start with a letter.

What it means

Error "Invalid project name {apiName}. May only contain alphanumeric characters or underscore and start with a letter." thrown in OpenAPITools/openapi-generator.

Source

Thrown at modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/CSharpClientCodegen.java:1218

        this.optionalEmitDefaultValuesFlag = flag;
    }

    public void setConditionalSerialization(boolean flag) {
        this.conditionalSerialization = flag;
    }

    public void setOptionalProjectFileFlag(boolean flag) {
        this.optionalProjectFileFlag = flag;
    }

    /**
     * Sets the api name. This value must be a valid class name.
     *
     * @param apiName The api name
     */
    public void setApiName(String apiName) {
        if (!"".equals(apiName) && (Boolean.FALSE.equals(apiName.matches("^[a-zA-Z0-9_]*$")) || Boolean.FALSE.equals(apiName.matches("^[a-zA-Z].*")))) {
            throw new RuntimeException("Invalid project name " + apiName + ". May only contain alphanumeric characters or underscore and start with a letter.");
        }
        this.apiName = apiName;
    }

    public void setOperationParameterSorting(String operationParameterSorting) {
        if (operationParameterSorting == null) {
            operationParameterSorting = "DEFAULT";
        }

        this.operationParameterSorting = SortingMethod.valueOf(operationParameterSorting.toUpperCase(Locale.ROOT));
    }

    public void setModelPropertySorting(String modelPropertySorting) {
        if (modelPropertySorting == null) {
            modelPropertySorting = "DEFAULT";
        }

        this.modelPropertySorting = SortingMethod.valueOf(modelPropertySorting.toUpperCase(Locale.ROOT));

View on GitHub (pinned to fcec517be3)

Solutions

1. Rename the project so it starts with a letter and contains only alphanumeric characters or underscores, e.g. via '--additional-properties packageName=MyApi'.

When it happens

Trigger: Thrown when the C# project name (derived from apiName/packageName) contains characters other than alphanumerics or underscore, or starts with a digit. Rename the project to match C# identifier rules.

Common situations: See trigger scenarios.

AI-assisted analysis of OpenAPITools/openapi-generator@fcec517be3 (2026-08-22). Data as JSON: /api/errors/6aa4bf76c5a8efc6. Report an issue: GitHub.