8 Best Onyx Alternatives in 2026 (Open Source)
Onyx — Open Source AI Platform - AI Chat with advanced features that works with every LLM. Provides a unified, low-latency internal knowledge representation for agents, replacing iterative MCP searches with instant context fetching.
These 8 open-source tools do the same job. They are ordered by how closely they match Onyx, with live GitHub data so you can see which projects are actively maintained.
| Tool | GitHub stars | Stars / 30d | Last commit |
|---|---|---|---|
| Onyx(original) | 32.3k | +2,692 | 2026-09-30 |
| LibreChat | 45.2k | +1,629 | 2026-09-30 |
| Open WebUI | 153.6k | +3,959 | 2026-09-21 |
| Open Assistant API | 367 | +1 | 2024-12-14 |
| MaxKB | 22.9k | +1,908 | 2026-09-28 |
| Casibase | 5.7k | +191 | 2026-09-29 |
| JeecgBoot | 48.0k | +4,004 | 2026-09-22 |
| Khoj | 37.5k | +3,129 | 2026-08-02 |
| SiYuan | 46.6k | +3,882 | 2026-09-29 |
1. LibreChat
Enhanced ChatGPT Clone: Features Agents, MCP, DeepSeek, Anthropic, AWS, OpenAI, Responses API, Azure, Groq, o1, GPT-5, Mistral, OpenRouter, Vertex AI, Gemini, Artifacts, AI model switching, message se
What sets it apart: Most feature-complete self-hosted ChatGPT alternative — uniquely combines agents, MCP, code interpreter, image gen, and multi-user auth in one package, unlike single-provider UIs
Best for: Organizations wanting a private, self-hosted ChatGPT replacement; Teams needing multi-user AI platform with access control and audit
2. Open WebUI
User-friendly AI Interface (Supports Ollama, OpenAI API, ...)
What sets it apart: Unlike LM Studio (desktop-only, personal use), Open WebUI is a full multi-user platform with RAG, RBAC, SCIM provisioning, 9 vector DBs, and Google Drive/OneDrive integration — the most feature-complete self-hosted ChatGPT alternative
Best for: Teams wanting a self-hosted ChatGPT alternative with full data control and Ollama integration; Organizations needing enterprise-grade AI platform with LDAP/SCIM/SSO and multiple vector DB backends
3. Open Assistant API
The Open Assistant API is a ready-to-use, open-source, self-hosted agent/gpts orchestration creation framework, supporting customized extensions for LLM, RAG, function call, and tools capabilities. It
What sets it apart: Open-source OpenAI Assistant API compatible service supporting multiple LLMs via One API, with RAG, web search, and local deployment
Best for: self-hosted-openai-assistant-alternative; multi-llm-assistant-apps; enterprise-local-deployment
4. MaxKB
🔥 MaxKB is an open-source platform for building enterprise-grade agents. 强大易用的开源企业级智能体平台。
What sets it apart: Combines enterprise-grade agent building with comprehensive RAG pipelines and MCP tool-use capabilities in an open-source package.
Best for: Enterprise agent development; Intelligent customer service systems; Corporate internal knowledge bases
5. Casibase
⚡️AI Cloud OS: Open-source enterprise-level AI knowledge base and MCP (model-context-protocol)/A2A (agent-to-agent) management platform with admin UI, user management and Single-Sign-On⚡️, supports Ch
What sets it apart: vs other knowledge base platforms: Enterprise-grade open-source AI Cloud OS with built-in SSO (Casdoor), admin UI, MCP/A2A agent management, and support for 10+ LLM providers out of the box
Best for: Enterprise teams needing a self-hosted AI knowledge base with admin UI; Organizations requiring SSO and user management for AI chatbots; Multi-model AI platform deployment with MCP/A2A support
6. JeecgBoot
【低代码v2.0，一句话即可生成整个系统】企业级AI低代码平台，一键生成前后端代码甚至整个系统。 AI Skills 一句话画流程、设计表单、生成报表、大屏。内置 AI应用平台涵盖：AI聊天、知识库、流程编排、MCP插件等，兼容主流大模型。引领AI低代码「Skills 生成 → 在线配置 → 代码生成 → 手工合并->
What sets it apart: Combines AI-powered natural language programming with enterprise low-code platform specifically for Java system generation and AI agent development.
Best for: Java developers automating repetitive coding tasks; Building enterprise AI applications with low-code; Creating AI agents with workflow orchestration
7. Khoj
Your AI second brain. Self-hostable. Get answers from the web or your docs. Build custom agents, schedule automations, do deep research. Turn any online or loca
What sets it apart: Open-source, self-hostable platform that scales from personal on-device AI to enterprise agents with custom knowledge and tools.
Best for: Users wanting self-hosted personal AI agents; Building custom agents for automation and research; Extending capabilities with local or cloud LLMs
8. SiYuan
An open-source, privacy-first, self-hosted knowledge workspace where humans and AI agents work together 开源、隐私优先、自托管的知识工作空间，让人与智能体在此协作
What sets it apart: Combines privacy-first, self-hosted knowledge management with native AI agent collaboration features for structured human-AI teamwork.
Best for: Teams needing private knowledge bases with AI assistance; Developers wanting self-hosted agent-augmented workspaces; Organizations requiring block-level knowledge management with AI integration
FAQ
- What are the best alternatives to Onyx?
- The closest open-source alternatives to Onyx are LibreChat, Open WebUI and Open Assistant API, followed by MaxKB, Casibase and JeecgBoot. They are ranked by how closely they match what Onyx does.
- Which Onyx alternative is the most popular?
- Open WebUI has the most GitHub stars among Onyx alternatives, with 153,644 stars.
- Which Onyx alternative is the most actively maintained?
- By recent activity, SiYuan (4,873 commits in the last 90 days) is the most actively developed alternative.