How to Build a CLI Tool as a Solo Developer

What You're Building

A CLI (command-line interface) tool is a program that runs in the terminal. Think tools like git, npm, or docker. Developers love CLI tools because they're fast, scriptable, and composable. As a solo developer, building a CLI tool is one of the most satisfying projects you can take on. Small scope, clear functionality, and a developer audience that appreciates good tooling.

I've built a couple of CLI tools that automate parts of my workflow. They're the kind of project where you can go from idea to published package in a weekend.

Difficulty & Timeline

Recommended Tech Stack

For most CLI tools, I'd use either Go or Node.js/TypeScript. Go compiles to a single binary with no runtime dependencies, which makes distribution dead simple. Node.js is faster to develop with if you're already in the JavaScript ecosystem and can distribute via npm.

For Go, use Cobra (the library behind kubectl, Hugo, and GitHub CLI). For Node.js, use Commander.js or oclif. Both handle argument parsing, help text, and subcommands out of the box.

Step-by-Step Plan

Phase 1: Foundation (Week 1)

Define what your CLI does in one sentence. "It does X when you type Y." If you can't say that clearly, your scope is too big.

Set up the project with your chosen framework. Create the main command and 1-2 subcommands. Get argument parsing and help text working. Focus on making the "happy path" work perfectly before handling edge cases.

I always start by hardcoding values and getting the output right, then work backwards to make those values configurable via flags and arguments. It's faster than trying to design the perfect CLI interface upfront.

Phase 2: Core Features (Week 1-2)

Build out the main functionality. Handle errors gracefully with clear, helpful error messages. Add a --verbose flag for debugging. Add color output using a library like chalk (Node.js) or fatih/color (Go) to make the terminal output readable.

Write tests for your core logic. CLI tools are easy to test because inputs and outputs are well-defined. A function takes arguments, does something, and produces output. That's inherently testable.

Phase 3: Polish & Launch (Week 2)

Create a README with clear installation instructions, usage examples, and a few GIFs showing the tool in action. Terminal GIFs are incredibly effective for CLI tools. Use a tool like VHS or asciinema to record them.

If you used Go, set up GoReleaser to build binaries for macOS, Linux, and Windows automatically. Publish to Homebrew if your audience is on macOS. If you used Node.js, publish to npm. Make installation a single command.

Monetization Strategy

Honestly, most CLI tools are hard to monetize directly. The developer audience expects open source tooling to be free. But there are proven models that work.

Sponsorships. If your tool gets popular (thousands of daily downloads), GitHub Sponsors and Open Collective can generate meaningful income. Tools like Homebrew and curl sustain their developers this way.

Paid tiers for teams. Open source the core tool, charge for team features like shared configs, analytics dashboards, or priority support. This is how tools like Tailwind CSS monetize.

Wrapper SaaS. Build a web dashboard or API around your CLI tool. The CLI is free, the hosted service costs money. This is the Terraform model. Free CLI, paid Terraform Cloud.

The best approach is usually to build the tool, get it popular, and then figure out monetization. Trying to charge $5 for a CLI tool that nobody knows about doesn't work.

Common Mistakes to Avoid

Making installation complicated. If users need to install 3 dependencies before they can use your tool, most won't bother. Go's single binary approach shines here. One download, it works. For Node.js, make sure npx your-tool works out of the box.

Poor error messages. "Error: invalid input" tells the user nothing. "Error: expected a file path but got a URL. Did you mean to use the --url flag?" actually helps. Good error messages are what separate professional tools from hobby projects.

No documentation. Your README is your marketing page, your user manual, and your support system all in one. If someone can't figure out how to use your tool from the README in under 2 minutes, you'll lose them.

Overcomplicating the interface. A good CLI tool does one thing well. The Unix philosophy exists for a reason. Don't build a Swiss Army knife when people just need a screwdriver.

Is This Worth Building?

As a business? Only if it becomes popular enough for sponsorships or serves as a funnel to a paid product. As a portfolio piece and developer tool? Absolutely.

CLI tools get you noticed in developer communities. A well-built, useful tool can land you thousands of GitHub stars, which translates to credibility, job offers, and consulting opportunities. Some of the most well-known developers in the industry built their reputation on open source CLI tools.

The development effort is low, the learning is high, and the potential reach is massive. If you've been wanting to contribute to the developer ecosystem, building a CLI tool is one of the best places to start.