Open Source Developer Tools
Discover 447 open source Developer Tools repositories from GitHub, each with an analysis of what it does, key features, use cases and alternatives. Developer Tools projects here are most often combined with Python, AI Agents and CLI. Last updated October 4, 2026.
447 repositories · updated October 4, 2026
gemini-cli: Use Gemini as an Agent in Your Terminal
Gemini CLI brings Gemini models into a terminal-based agent for working with code, files, shell commands, and web information. It suits developers who want interactive assistance or scriptable workflows, with support for custom tools through MCP.
hypothesis: Find Bugs with Property-Based Testing
Hypothesis is a Python testing library that generates inputs for properties your code should satisfy. Use it to explore edge cases that example-based tests may miss and to get simplified failing cases when a bug is found.
mcphub: Connect and Manage MCP Servers Through One Gateway
MCPHub is a self-hosted gateway and control plane for connecting MCP clients to local and remote MCP servers. It centralizes routing, access controls, credentials, logs, and health monitoring.
openllmetry: Observe LLM Applications with OpenTelemetry
OpenLLMetry adds OpenTelemetry-based tracing and metrics for LLM applications, providers, frameworks, and vector databases. It suits teams that want AI-specific observability in their existing telemetry stack rather than a separate monitoring format.
json4u: Explore, Compare, and Process JSON in a Web App
JSON For You is a web-based tool for inspecting, editing, validating, comparing, and querying JSON. Its graph and table views help developers work with nested data, while jq support and CSV import/export cover common processing tasks.
hyperpb-go: Parse Protobuf Messages Faster in Go
hyperpb-go is a Go library for fast, read-only parsing of dynamic Protobuf messages. It targets services that load schemas at runtime and need efficient reflection-based processing, with trade-offs including an experimental API and support limited to amd64 and arm64.
zen: Run Business Rules Across Languages
ZEN is a Rust-based business rules engine that evaluates portable JSON decisions consistently across multiple programming languages. Use it to make complex business logic readable, testable, and reusable across services and applications.
SWE-agent: Use Language Models to Fix GitHub Issues
SWE-agent gives a language model tools to work on real software repositories, including diagnosing and attempting to fix GitHub issues. It is designed for software engineering research and configurable coding tasks, though its maintainers now recommend mini-SWE-agent for new use.
run-gemini-cli: Run Gemini CLI in GitHub Actions
run-gemini-cli brings Gemini CLI into GitHub Actions for automated coding tasks and on-demand help in issues and pull requests. It suits teams that want AI-assisted reviews, triage, or repository changes within their existing workflows.
extension.js: Build Cross-Browser Web Extensions
Extension.js is a TypeScript-based framework and CLI for developing browser extensions across Chrome, Edge, Firefox, and Safari. It provides a shared workflow for development and production builds, with framework support and no build configuration required.
react-antd-low-code: Build React Apps with a Low-Code Platform
A lightweight low-code platform project built with Next.js, Ant Design, and TypeScript. Its README documents a full-stack setup with Prisma, PlanetScale, and NextAuth.js, but does not detail the editor’s capabilities.
editly: Create Videos from Code and Media Clips
Editly is a Node.js command-line tool and JavaScript API for assembling videos from clips, images, titles, and audio. It suits creators and developers who want repeatable edits defined in code, with transitions and overlays rendered through ffmpeg.