Best Open Source Developer Tools Tools in 2026

CopilotKit

AI & Machine Learning Web Development Developer Tools

Add in-app AI copilot chat and actions to any React application

stars 30.5Klicense MITlang TypeScript

AI Agents AI SDK Developer Framework+4

Letta

LLMOps & AI Tooling AI & Machine Learning Developer Tools

Give your LLM agents persistent memory across every conversation

stars 2.4Klicense Apache-2.0lang TypeScript

AI Agents LLM LLMOps+3

Logto

Security & Monitoring Developer Tools APIs & Integration

Multi-tenant auth platform with SSO, RBAC, and social login

stars 11.9Klicense MPL-2.0lang TypeScript

Authentication Authorization API Infrastructure+5

FerretDB

Databases & Storage Developer Tools Backend Development

Run MongoDB apps on PostgreSQL with no code changes needed

stars 10.9Klicense Apache-2.0lang Go

Database Self Hosted Developer Tools+2

ZITADEL

Security & Monitoring APIs & Integration Developer Tools

Open source identity platform with SSO, RBAC, and multi-tenancy

stars 13.6Klicense AGPL-3.0lang Go

Authentication Authorization Security+4

Better Auth

Backend Development Security & Monitoring Developer Tools

Drop-in TypeScript auth with MFA, SSO, and multi-tenancy support

stars 28Klicense MITlang TypeScript

Authentication Self Hosted Developer Framework+4

Botpress

AI & Machine Learning Customer Support Developer Tools

Visual chatbot builder with LLM integration and live deployment

stars 22.6Klicense MITlang JavaScript

Chatbots AI Agents LLM+4

Languine

AI & Machine Learning Developer Tools DevOps & CI/CD

Keep translations in sync with code changes via AI-powered CLI

stars 1.9Klang TypeScript

Workflow Automation AI Coding Assistant CI/CD Platforms+4

Kutt

Web Development Marketing & Growth Developer Tools

Self-hosted URL shortener with analytics and custom domains

stars 10.7Klicense MITlang JavaScript

Link Management & Shorteners Self Hosted Web Analytics+2

Yaak

Developer Tools APIs & Integration Web Development

Local-first API client for HTTP, GraphQL, and WebSocket

stars 18.5Klicense MITlang TypeScript

API Client API Development Tools Testing+3

Kanri

Product & Project Management Business & Productivity Developer Tools

Local-first Kanban board that stores all data in a JSON file

stars 1.9Klicense GPL-3.0lang Vue

Project Management Task Management Local-first+3

Joplin

Business & Productivity IT Management Developer Tools

Open source note-taking app with Markdown and sync support

stars 54.5Klicense NOASSERTIONlang TypeScript

Note-taking Apps Knowledge Management File Sync & Storage+3

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CopilotKit

Letta

Logto

FerretDB

ZITADEL

Better Auth

Botpress

Languine

Kutt

Yaak

Kanri

Joplin

CopilotKit

Letta

Logto

FerretDB

ZITADEL

Better Auth

Botpress

Languine

Kutt

Yaak

Kanri

Joplin