Hygen

Hygen is a command-line code generator for creating project files and updating existing ones from templates. It is a strong fit for developers and teams that want reusable scaffolding kept with the code it supports. Its flexible generator workflows serve broad boilerplate needs, though it does not provide schema-to-code generation.

Overview

Hygen organizes self-contained generators by folder, with that structure determining the commands users run. Templates can sit in a project-local _templates folder, so teams can maintain scaffolding alongside application code and review template changes in the same pull request. This is a practical approach when generator conventions should evolve with a project rather than live separately.

The main organizational constraint is that Hygen does not discover templates nested down folder trees by default. The maker says this preserves startup performance, but teams with deeply nested template collections must account for the discovery limit in how they structure generators.

Key features

• Generator scaffolds: Built-in options, including a prompt-driven scaffold, help users create generators. Folder-based commands keep each generator self-contained, which suits projects with several distinct code-generation tasks.
• EJS templates and frontmatter: Template bodies use EJS, and frontmatter can set a destination path. String or regular-expression subactions can select matching files within an action, giving generators a way to target file changes.
• File creation and injection: Hygen can add new files or insert template content into existing files. That makes it useful for both initial scaffolding and repeatable edits to established project structure.
• Arguments and prompts: Generators can accept command-line arguments, use interactive prompts, or guide users through multi-step prompt flows. This accommodates both scripted use and workflows that need user input.
• Shell commands and dry runs: Templates can run shell commands, and the Quick Start documents a --dry option for test-running generators. Shell execution broadens what a generator can do, while making it important to review generator changes as executable project code.

Hygen was built to reduce boilerplate in React, Redux, and Node.js work, but its maker says it can be used with any technology. The site presents Redux, Express.js, and React Native examples. Installation options include Homebrew on macOS, global npm or Yarn installation, npx, and standalone binaries; the Quick Start says binaries are available for every major platform.

Pricing

Hygen is open source under the MIT license and has one free plan: free. It is distributed through npm, Homebrew, npx, and standalone binaries. There is no paid tier to weigh against the free version, making it a straightforward choice for individuals or teams seeking a no-cost generator.

Platforms

Hygen is available on Linux, macOS, and Windows. Its CLI distribution and standalone binaries make it suited to developers working across those desktop environments.

Who it's for

Choose Hygen if you want project-specific generators that can create files, modify existing ones, and keep templates reviewable alongside code. Its prompt and argument support fits both interactive project setup and repeatable command-line workflows. It is less suitable when schema-to-code generation is central, or when automatic discovery through deeply nested template folders is a requirement.

Pros and cons

• Pro — Templates live with the project: Teams can keep generator changes in the same repository and review them alongside related code.
• Pro — More than file scaffolding: Prompts, arguments, injection into existing files, shell commands, and dry runs support varied generation workflows.
• Pro — Free and open source: The MIT-licensed tool has no paid plan to outgrow.
• Con — No default deep-folder discovery: Nested template collections require deliberate organization because Hygen does not find templates down folder trees automatically.
• Con — No schema-to-code generation: Teams looking specifically to generate code from schemas should choose a tool built for that task.

Alternatives

For a broad comparison, browse Code Generators.

• quicktype is another free, open-source option, with a web app and CLI.
• SQLDelight is a free, open-source Kotlin SQL code generation library; choose it when Kotlin SQL generation is the specific need.
• Angular CLI is a free option for projects using Angular's CLI workflow.
• Fern offers a free plan with limits of 10 team members, 1,000 pages, 250 AI credits per month, 2,000 page generations per month, and one site; choose it when those page and AI capabilities fit the task.
• JHipster is a free, open-source development platform for teams seeking a broader development platform.
• Nx has a free Hobby plan capped at 50,000 monthly credits, five contributors, and 10 concurrent CI connections; its free tier also includes community support.
• OpenAPI Generator is a free, open-source option for generating API clients, server stubs, documentation, and configurations.
• Spring Initializr is a free, Apache 2.0-licensed alternative.

Verdict

Hygen is a sound choice for developers and teams who want a free, project-local generator with flexible prompts and the ability to create or edit files. Its strongest reason to choose it is that generator workflows can live and change alongside the code they serve. Look elsewhere for schema-to-code generation or if automatic discovery through nested template folders is essential.