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
cytoolz: Speed Up Python Functional Utilities
cytoolz provides Cython implementations of toolz utilities for working with iterables, functions, and dictionaries. Use it when toolz-compatible APIs and iterator-friendly processing need more speed, or when Cython projects need its C API.
linctl: Manage Linear Issues from the Command Line
linctl is a Go CLI for managing Linear issues, projects, teams, users, and comments. It suits developers and agents that need scriptable access to Linear through JSON output, GraphQL, or schema-driven MCP commands.
lefthook: Manage Git Hooks Across Projects
Lefthook is a fast, Go-based manager for configuring and running Git hooks across projects and languages. Use it to automate checks around commits and pushes, with options for parallel jobs, file filtering, scripts, and local overrides.
teller: Manage Secrets from the Command Line
Teller is a Rust CLI for using secrets from cloud providers and vaults without storing them in shell scripts or local environment files. It also supports secret scanning, redaction, and provider-to-provider copying.
keploy: Record and Replay API Tests and Mocks
Keploy records application traffic and replays it as API and integration tests with mocks for dependent services. It suits developers and QA teams seeking repeatable tests from real usage without changing application code.
context-engineering-intro: Guide AI Coding Assistants with Project Context
A Claude Code-oriented template for giving coding assistants project rules, examples, and feature requirements before implementation. It turns feature requests into Product Requirements Prompts with implementation steps and validation guidance.
CertoraProver: Formally Verify Smart Contracts
Certora Prover checks smart contracts against formal specifications to find violations before deployment. It targets developers and security teams working with EVM-based chains, Solana, or Stellar who need automated verification.
SaaS-Boilerplate: Build SaaS apps with Next.js
A TypeScript starter for building full-stack SaaS applications with Next.js. It bundles authentication, team tenancy, permissions, database access, localization, and testing so developers can start from an integrated foundation.
Framely: Build Multi-Tenant Websites With Drag-and-Drop
Framely is a Next.js boilerplate for building multi-tenant website editors with drag-and-drop page creation and custom domain support. It suits developers who want a starting point for a hosted website-builder product rather than a standalone page-design tool.
sandbox-sdk: Run Code in Cloudflare Edge Sandboxes
Cloudflare Sandbox SDK helps Workers run untrusted or generated code in Linux containers managed through Durable Objects. It adds file transfer, S3-compatible mounts, and directory backups for isolated per-user or per-task environments.
radon-ide: Build and Debug React Native Apps in Your Editor
Radon IDE adds an integrated development workflow for React Native and Expo projects in VSCode, Cursor, and Windsurf. It combines simulator previews, debugging, inspection, and device controls, and is distributed under a commercial license with a free trial.
httptoolkit: Inspect and Debug HTTP Traffic
HTTP Toolkit is a cross-platform tool for inspecting, rewriting, and mocking HTTP(S) traffic. It helps developers debug clients and services by capturing requests and responses, testing custom requests, and simulating endpoints.