Hygen

Hygen is a project-based code generator that creates code from templates, helping teams produce boilerplate and other files within a project. Its generators are self-contained, and their folder structure defines the commands available. Hygen checks for a local `_templates` folder, so templates can sit beside project code. Built-in scaffolds, including a prompt-driven option, help create generators. Templates use EJS with frontmatter that can specify a destination path. A generator can create files, insert content into existing files, accept command-line arguments, and guide users through one or more prompts. Templates can also run shell commands, and actions can select matching files by string or regular expression. A documented `--dry` option lets users run a generator without applying its changes. Hygen was built to ease boilerplate work for React, Redux, and Node.js, but its maker says it can be used with any technology; examples include Redux, Express.js, and React Native. It is free and open source under the MIT license, with installation options including Homebrew, npm, Yarn, npx, and standalone binaries. It runs on Linux, macOS, and Windows.

Hygen offers a project-local way to automate code generation with flexible templates, prompts, and file operations. Its default template discovery stays within the expected folder structure, so teams with nested template layouts should account for that limit.

Hygen suits developers and teams that want reusable, project-local templates for generating or updating code. It can support boilerplate workflows across technologies, with examples for React, Redux, Express.js, and React Native.

Hygen is a command-line generator that keeps reusable scaffolding inside the project it serves. It fits developers and teams standardizing boilerplate across React, Node.js, or other stacks. Choose it for versioned, programmable file generation; look elsewhere if you need schema-to-code output.

Overview

Hygen organizes self-contained generators as project commands: their folder structure defines how each generator is invoked. A local _templates directory keeps those generators beside application code, so template changes can be reviewed with related code in the same pull request. That project-local model is a strong fit for repositories with conventions that evolve alongside the product.

There is one structural trade-off. Hygen does not search down nested folder trees automatically. This preserves startup performance, but teams with deeply layered template libraries must accommodate that discovery boundary. The tool began around React, Redux, and Node.js boilerplate while remaining usable with any technology.

Key features

• Generator scaffolding: Built-in scaffolds, including a prompt-driven creator, help teams add generators without designing every folder and command manually.
• EJS and frontmatter templates: Template bodies use EJS, while frontmatter can set a to destination path. This supports output tailored to each project location rather than fixed filenames.
• File creation and injection: Actions can add new files or insert generated content into existing files. String or regular-expression subactions can select matching files within an action, which is useful for targeted updates.
• Arguments and prompts: Generators accept command-line arguments, interactive questions, and multi-step prompt flows. Teams can expose routine choices without maintaining separate templates for every variation.
• Shell commands and dry runs: Templates may run shell commands, extending generation beyond file writing. That power warrants code-review discipline because generator changes can execute commands. The documented --dry option lets users preview a run before applying changes.
• Project scaffolding: Hygen supports custom templates and a CLI, but it does not provide schema-to-code generation. It is therefore a general boilerplate engine, not an API- or database-schema compiler.

Pricing

Hygen is open source and free: the Open source plan costs nothing. There is no paid tier, trial period, seat charge, or stated usage quota. Distribution through npm, Homebrew, npx, and standalone binaries keeps the cost model straightforward for individuals and teams, while the MIT license permits use under its terms.

Platforms

Hygen supports Linux, macOS, and Windows. Installation options include Homebrew on macOS, global npm or Yarn packages, npx, and standalone binaries. IDE plugins are listed as supported, although the core workflow remains command-line oriented.

Who it's for

Hygen suits developers who repeatedly create similarly structured files and teams that want those rules versioned with their repositories. It is especially practical for React, Redux, Node.js, Express.js, and React Native workflows, while its template model can serve other technologies. Teams with nested template trees or a requirement for schema-driven generation should consider another category of tool.

Pros and cons

Pros

• Project-local ownership: Templates live with the code they generate, making convention changes visible in normal pull requests.
• Broad generation control: EJS, frontmatter, prompts, arguments, injections, file selection, and shell commands cover more than simple file copying.
• No licensing cost: The MIT-licensed, open-source distribution has no paid plan or seat limits.
• Multiple installation paths: npm, Yarn, npx, Homebrew, and binaries accommodate different development environments.

Cons

• Limited default discovery: Nested template folders are not traversed automatically, complicating deeply hierarchical repositories.
• Command-line emphasis: Teams seeking a schema-to-code workflow will not find that capability in Hygen.
• Executable templates need oversight: Shell-command support increases flexibility but also raises the review burden for shared generators.

Alternatives

SQLDelight is the better choice when Kotlin SQL code generation across Android, iOS, Linux, macOS, web, and Windows is the priority.

Angular CLI fits teams wanting a free, Angular-focused command-line tool with no stated paid plans or usage limits.

APIMatic is preferable for API-focused generation with a hosted free tier capped at one API, 10 endpoints, two programming languages, and one team member.

NestJS CLI is the focused alternative for MIT-licensed Nest projects installed through npm.

quicktype suits users who want open-source web and CLI generation under Apache-2.0.

ts-proto is an Apache-2.0 open-source option for its specific generation workflow.

Backstage is the broader open-source framework choice for platform-oriented projects.

Fern is worth considering when a freemium hosted workflow with team, page, AI-credit, and generation quotas is acceptable.

Verdict

Hygen is a strong recommendation for developers and teams that want programmable, reviewable scaffolding stored beside their code. Its free MIT-licensed distribution and rich prompt and file-operation model are the main reasons to choose it. Look elsewhere for schema-to-code generation or automatic discovery across deeply nested template trees.