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OpenAPI 3 Generator

Free plan LinuxSelf-hosted

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OpenAPI 3 Generator's own site

What OpenAPI 3 Generator is

OpenAPI 3 Generator is a free, open-source, self-hosted tool for Linux that turns an OpenAPI 3 definition into generated code, documentation, and other outputs. Its command-line interface accepts an OpenAPI file or URL together with a template. You can install it globally with npm using `npm install -g openapi3-generator`; the package exposes both `og` and `openapi3-generator` commands. The project lists Node.js v7.6 or later as a requirement and shows YAML as an example input format. Templates may combine static files, Handlebars templates, and path templates that create one file for each OpenAPI path. Custom templates can add Handlebars helpers in a `.helpers` directory and partials in `.partials`. Templates receive the OpenAPI specification and an `openapi.endpoints` value containing first-level endpoints. Dependencies include Handlebars, YAML parsing, OpenAPI validation, and Markdown generation. The repository uses the Apache License 2.0 and names Fran Méndez and Richard Klose as authors. An Issues section provides a project support channel.

Who it suits

It suits developers who need generated code or documentation from OpenAPI 3 definitions and want template-level control. Linux and self-hosted deployment fit teams managing their own environment.

What it does well

  • Free and open-source
  • Accepts OpenAPI files or URLs
  • Custom Handlebars helpers and partials
  • Generates files per API path
  • Apache License 2.0

What to know first

  • Requires Node.js v7.6 or later
  • Linux and self-hosted only
  • No free trial

Limits

The listed requirements include Node.js v7.6 or later, and the tool is provided for Linux in a self-hosted model.

Getting started

  1. Install Node.js v7.6 or later
  2. Run `npm install -g openapi3-generator`
  3. Prepare an OpenAPI file or URL and a template
  4. Run the installed `og` or `openapi3-generator` command with those inputs

Verdict

OpenAPI 3 Generator focuses on command-line generation from OpenAPI 3 inputs, with extensive template customization. It is a practical fit when you want to run the generator yourself and control the produced files.

Questions

Is OpenAPI 3 Generator free?

Yes. It is listed as free and open source, with a free plan and no free trial.

What platforms does it support?

The listed platform is Linux, with self-hosted deployment.

How is it installed?

The README gives `npm install -g openapi3-generator` for global npm installation.

What inputs does the CLI accept?

It accepts an OpenAPI file or URL and a template.

Can templates be customized?

Yes. Templates can use static files, Handlebars, path templates, custom helpers in `.helpers`, and partials in `.partials`.

What license does it use?

The repository uses the Apache License, Version 2.0.

Facts from OpenAPI 3 Generator's own pages

CLI
The tool can be installed globally with npm and run from the command line as `og`. · github.com, 4 Oct 2026
CLI input
The CLI accepts an OpenAPI file or URL and a template as inputs. · github.com, 10 Oct 2026
Customization
A template can define Handlebars helpers in a `.helpers` directory and partials in a `.partials` directory. · github.com, 10 Oct 2026
Data available
The generator passes the OpenAPI specification to templates and provides `openapi.endpoints` for first-level endpoints. · github.com, 10 Oct 2026
Dependencies
The package lists Handlebars, YAML parsing, OpenAPI validation, and Markdown generation dependencies. · github.com, 4 Oct 2026
Dependency
The package lists Handlebars as a dependency. · github.com, 10 Oct 2026
Distribution
The README documents global npm installation and command-line use. · github.com, 10 Oct 2026
Input
The CLI accepts an OpenAPI file or URL and a template as arguments. · github.com, 4 Oct 2026
Input formats
The README shows an OpenAPI definition in YAML format as an example input. · github.com, 4 Oct 2026
Installation
The README gives `npm install -g openapi3-generator` as the CLI installation command. · github.com, 10 Oct 2026
License
The repository includes an Apache License, Version 2.0. · github.com, 10 Oct 2026
Maintainers
The README lists Fran Méndez and Richard Klose as authors. · github.com, 10 Oct 2026
Purpose
OpenAPI 3 Generator uses an OpenAPI 3 definition to generate code, documentation, and other outputs. · github.com, 10 Oct 2026
Requirements
The project lists Node.js v7.6 or later as a requirement. · github.com, 4 Oct 2026
Runtime requirement
The README lists Node.js v7.6+ as a requirement. · github.com, 10 Oct 2026
Support channel
The repository page provides an Issues section for the project. · github.com, 10 Oct 2026
Template data
Templates receive the OpenAPI specification and an `openapi.endpoints` value containing first-level endpoints. · github.com, 4 Oct 2026
Templates
Templates can contain static files, Handlebars templates, and path templates that generate a file for each OpenAPI path. · github.com, 10 Oct 2026

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