10 Weird OSS Projects You Actually Need

Your GitHub stars list probably has a bunch of “use this later” repos you’ve never actually opened. These aren’t those. Each one solves a very specific pain point, and most of them are things you’ll reach for within three days of installing them.

TL;DR

10 practical open-source tools you likely don’t have yet: code visualization, local CI execution, terminal UI generation, API testing, Git workflow enhancement, and more. Each has a clear use case and isn’t trying to be a general-purpose platform.

1. Carbon — Turn Code Snippets into Designer-Quality Images

GitHub: carbon-app/carbon

Posting code screenshots on Twitter or tech blogs with a raw screenshot looks rough. Carbon lets you choose a theme, font, and background color and export a polished PNG/SVG.

Good for: tech blog posts, presentation slides, README example images. Not for: code that needs to be copy-pasted — images can’t be copied.

2. Excalidraw — Whiteboard-Style Architecture Diagrams

GitHub: excalidraw/excalidraw

Lucidchart and Draw.io diagrams look too formal. Sometimes you need a “quick sketch” feel. Excalidraw produces deliberately hand-drawn style diagrams, is fully open-source, self-hostable, and supports real-time collaboration and SVG export.

There’s a VS Code extension that opens .excalidraw files directly in the editor.

3. nektos/act — Run GitHub Actions Locally

GitHub: nektos/act

Pushing to test CI workflow is one of the biggest time wasters in development. act lets you run GitHub Actions workflows locally with Docker, making iteration ten times faster.

# Install (macOS)
brew install act

# Run all workflows for push events
act push

# Run a specific job
act -j build

Limitation: some GitHub-specific actions (like actions/checkout) require extra configuration to work correctly locally.

4. Hoppscotch — Open-Source Postman Alternative, Self-Hostable

GitHub: hoppscotch/hoppscotch

Postman’s free tier is increasingly restricted, and it stores your API collections in their cloud. Hoppscotch is fully open-source, supports REST, GraphQL, and WebSocket testing, and can be self-hosted so your data stays with you.

5. Bun Shell ($) — Shell Scripts in JavaScript

GitHub: oven-sh/bun

child_process.exec is ugly, shelljs is old, Bun’s built-in $ lets you write shell syntax directly in JavaScript/TypeScript:

import { $ } from "bun";

const result = await $`ls -la`.text();
const files = await $`find . -name "*.ts"`.lines();

Cross-platform (works on Windows), fully typed, and the modern alternative for build scripts in Node.js projects.

6. Ink — Build Terminal UIs with React

GitHub: vadimdemedes/ink

You don’t need to learn ncurses to build interactive CLIs. Ink lets you write terminal interfaces as React components:

import React from 'react';
import { render, Text, Box } from 'ink';

const App = () => (
  <Box flexDirection="column">
    <Text color="green">Build complete!</Text>
    <Text dimColor>3 files processed</Text>
  </Box>
);

render(<App />);

Gatsby CLI and Parcel’s CLI are both built with Ink.

7. Slidev — Presentations for Engineers, Written in Markdown

GitHub: slidevjs/slidev

If you hate PowerPoint but need to give technical talks, Slidev lets you write slides in Markdown with Vue components, syntax-highlighted code blocks, interactive demos, and PDF/web export.

For engineers, putting presentation slides in Git for version control is itself a compelling feature.

8. Zod — Runtime Type Validation for TypeScript

GitHub: colinhacks/zod

TypeScript types disappear at runtime. When you receive data from an API, you can’t be certain it matches your expected type. Zod lets you define a schema and validate at runtime:

import { z } from "zod";

const User = z.object({
  id: z.number(),
  name: z.string(),
  email: z.string().email(),
});

const user = User.parse(apiResponse); // throws with clear error if invalid

Works especially well with tRPC — share the same schema between front-end and back-end.

9. Playwright — Modern E2E Testing

GitHub: microsoft/playwright

Selenium’s API design dates to 2004. Playwright, released by Microsoft in 2020, is the modern alternative: supports Chromium, Firefox, and WebKit, has auto-waiting (no manual sleep calls), and includes codegen to record interactions and generate test code.

npx playwright codegen https://your-app.com

10. Mermaid — Diagrams Directly in Markdown

GitHub: mermaid-js/mermaid

GitHub, Notion, and GitLab all support Mermaid natively. Write text in Markdown, get rendered flowcharts, sequence diagrams, and Gantt charts. No diagramming tool needed:

graph LR
    A[User Request] --> B[API Gateway]
    B --> C[Service A]
    B --> D[Service B]

Architecture diagrams living in the same repo as code and going through code review — that’s what documentation should look like.

Summary

What these 10 tools have in common: they each solve one specific problem instead of trying to be an “everything platform.” That focus is exactly what makes them easy to evaluate, easy to adopt, and actually useful in practice.

References

• carbon-app/carbon
• excalidraw/excalidraw
• nektos/act
• hoppscotch/hoppscotch
• vadimdemedes/ink
• slidevjs/slidev
• colinhacks/zod
• microsoft/playwright
• mermaid-js/mermaid