CLI Reference

Synopsis

openapi-codegen [OPTIONS] <input> [output]
openapi-codegen --input <file-or-url> --output <file>

Arguments

<input>

Required. Path to a local OpenAPI specification file (JSON or YAML) or a URL to a remote spec.

# Local file
openapi-codegen ./specs/api.yaml

# Remote URL
openapi-codegen https://example.com/api/openapi.json

[output]

Optional. Path to the output C# file. If omitted, the generated code is written to stdout.

# Write to file
openapi-codegen spec.yaml Models.cs

# Write to stdout
openapi-codegen spec.yaml

Options

-i, --input <path>

Input OpenAPI specification file path or URL. Alternative to the positional <input> argument.

openapi-codegen --input spec.yaml --output Models.cs

-o, --output <path>

Output C# file path. Alternative to the positional [output] argument. The directory is created automatically if it doesn’t exist.

openapi-codegen spec.yaml --output src/Generated/Models.cs

-n, --namespace <name>

C# namespace for the generated types.

• Default: GeneratedModels

openapi-codegen spec.yaml -o Models.cs -n MyApp.Api.Models

--no-doc-comments

Disable generation of XML documentation comments from OpenAPI descriptions.

openapi-codegen spec.yaml -o Models.cs --no-doc-comments

--no-header

Disable the auto-generated file comment header (// <auto-generated>...).

openapi-codegen spec.yaml -o Models.cs --no-header

--no-default-non-nullable

Don’t treat properties with default values as non-nullable.

openapi-codegen spec.yaml -o Models.cs --no-default-non-nullable

--no-add-default-values

Don’t add default values from the OpenAPI spec to the generated properties.

openapi-codegen spec.yaml -o Models.cs --no-add-default-values

--mutable-arrays

Use List<T> instead of IReadOnlyList<T> for array properties.

openapi-codegen spec.yaml -o Models.cs --mutable-arrays

--mutable-dictionaries

Use Dictionary<string, T> instead of IReadOnlyDictionary<string, T> for map/additionalProperties types.

openapi-codegen spec.yaml -o Models.cs --mutable-dictionaries

-v, --version

Display the tool version and exit.

openapi-codegen --version

-h, --help

Display the help message and exit.

openapi-codegen --help

Exit Codes

Code	Meaning
0	Success
1	Error (missing input, parse failure, etc.)

Examples

# Basic generation
openapi-codegen petstore.yaml -o Models.cs

# Custom namespace
openapi-codegen petstore.yaml -o Models.cs -n PetStore.Models

# From URL with all options disabled
openapi-codegen https://example.com/api.json \
  -o Models.cs \
  --no-doc-comments \
  --no-header \
  --no-default-non-nullable \
  --no-add-default-values \
  --mutable-arrays \
  --mutable-dictionaries

# Preview to stdout
openapi-codegen spec.yaml | head -50

# Named flags style
openapi-codegen --input spec.yaml --output Models.cs --namespace MyApp