OpenAPI 3 Generator
OpenAPI 3 Generator is a free, open-source command-line tool that uses an OpenAPI 3 definition to generate code, documentation, and other outputs.
What OpenAPI 3 Generator is
OpenAPI 3 Generator is a free, open-source command-line tool that uses an OpenAPI 3 definition to generate code, documentation, and other outputs. The npm package installs globally with `npm install -g openapi3-generator`; its commands include `og` and `openapi3-generator`. The CLI accepts an OpenAPI file or URL together with a template, and the project lists Node.js v7.6 or later as a requirement. 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 plus `openapi.endpoints`, containing first-level endpoints. The package lists dependencies for Handlebars, YAML parsing, OpenAPI validation, and Markdown generation. YAML is shown as an example input format. The software is Apache License 2.0, listed for Linux and self-hosted use, and the repository provides an Issues section for support.
Good
- Free and open source
- Generates code, documentation, and other outputs
- Accepts OpenAPI files or URLs
- Custom Handlebars helpers and partials
- Provides per-path template generation
Watch out
- Requires Node.js v7.6 or later
- Command-line workflow requires npm installation
- Listed platform is Linux
- No free trial
Who it suits
It suits developers generating project files from OpenAPI definitions in Linux or self-hosted environments. Teams needing custom Handlebars-based output templates can use its helper, partial, and path-template structure.
Verdict
OpenAPI 3 Generator gives developers a template-driven CLI for turning OpenAPI definitions into tailored outputs. Its self-hosted Linux focus and Node.js requirement fit technical teams comfortable with command-line tooling.
The facts
Each one read from OpenAPI 3 Generator's own pages, with the date it was checked.
What it does
- CLI
- The tool can be installed globally with npm and run from the command line as `og`.checked 4 Oct 2026
- CLI input
- The CLI accepts an OpenAPI file or URL and a template as inputs.checked 10 Oct 2026
- Customization
- A template can define Handlebars helpers in a `.helpers` directory and partials in a `.partials` directory.checked 10 Oct 2026
- Data available
- The generator passes the OpenAPI specification to templates and provides `openapi.endpoints` for first-level endpoints.checked 10 Oct 2026
- Dependencies
- The package lists Handlebars, YAML parsing, OpenAPI validation, and Markdown generation dependencies.checked 4 Oct 2026
- Dependency
- The package lists Handlebars as a dependency.checked 10 Oct 2026
- Distribution
- The README documents global npm installation and command-line use.checked 10 Oct 2026
- Input
- The CLI accepts an OpenAPI file or URL and a template as arguments.checked 4 Oct 2026
- Input formats
- The README shows an OpenAPI definition in YAML format as an example input.checked 4 Oct 2026
- Installation
- The README gives `npm install -g openapi3-generator` as the CLI installation command.checked 10 Oct 2026
- License
- The repository includes an Apache License, Version 2.0.checked 10 Oct 2026
- Maintainers
- The README lists Fran Méndez and Richard Klose as authors.checked 10 Oct 2026
- Purpose
- OpenAPI 3 Generator uses an OpenAPI 3 definition to generate code, documentation, and other outputs.checked 10 Oct 2026
- Requirements
- The project lists Node.js v7.6 or later as a requirement.checked 4 Oct 2026
- Runtime requirement
- The README lists Node.js v7.6+ as a requirement.checked 10 Oct 2026
- Support channel
- The repository page provides an Issues section for the project.checked 10 Oct 2026
- Template data
- Templates receive the OpenAPI specification and an `openapi.endpoints` value containing first-level endpoints.checked 4 Oct 2026
- Templates
- Templates can contain static files, Handlebars templates, and path templates that generate a file for each OpenAPI path.checked 10 Oct 2026
