8 Best Open Assistant API Alternatives in 2026 (Open Source)
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. Open-source OpenAI Assistant API compatible service supporting multiple LLMs via One API, with RAG, web search, and local deployment
These 8 open-source tools do the same job. They are ordered by how closely they match Open Assistant API, with live GitHub data so you can see which projects are actively maintained.
| Tool | GitHub stars | Stars / 30d | Last commit |
|---|---|---|---|
| Open Assistant API(original) | 367 | +1 | 2024-12-14 |
| Astra Assistant API | 207 | +-0 | 2025-08-18 |
| TaskingAI | 5.4k | +4 | 2024-10-31 |
| workgpt | 731 | +-0 | 2023-06-23 |
| RestGPT | 1.4k | +2 | 2023-09-28 |
| CodeFuse-ChatBot | 1.3k | +1 | 2024-07-01 |
| DB-GPT | 20.1k | +270 | 2026-09-28 |
| LibreChat | 45.2k | +1,629 | 2026-09-30 |
| OpenAI Developers Responses API reference | 2.5k | +30 | 2026-09-30 |
1. Astra Assistant API
Drop in replacement for the OpenAI Assistants API
What sets it apart: Drop-in OpenAI Assistants API v2 replacement supporting 30+ LLM providers via LiteLLM, backed by AstraDB vector storage
Best for: openai-assistant-api-with-alternative-llms; multi-provider-assistant-apps; astradb-users
2. TaskingAI
The open source platform for AI-native application development.
What sets it apart: BaaS platform for LLM agent development with unified API across hundreds of models, decoupled modular management of tools/RAG/models, and one-click production deployment
Best for: llm-app-backend-service; multi-tenant-ai-platforms; unified-multi-model-management
3. workgpt
A GPT agent framework for invoking APIs
What sets it apart: vs LangChain / AutoGPT: TypeScript-native agent framework with first-class OpenAPI integration — any API with an OpenAPI spec becomes an LLM tool automatically, with built-in web browsing and structured output extraction
Best for: Automating multi-API workflows from natural language directives; Web scraping and structured data extraction with LLM intelligence; TypeScript developers wanting an agent framework with OpenAPI-first design
4. RestGPT
An LLM-based autonomous agent controlling real-world applications via RESTful APIs
What sets it apart: vs basic API wrappers: iterative coarse-to-fine planning combining high-level task decomposition with fine-grained API selection — addresses practical challenges of multi-step API orchestration
Best for: Automating complex multi-step REST API workflows; Research into LLM planning for API orchestration; Testing LLM capabilities against realistic API integration tasks
5. CodeFuse-ChatBot
An intelligent assistant serving the entire software development lifecycle, powered by a Multi-Agent Framework, working with DevOps Toolkits, Code&Doc Repo RAG, etc.
What sets it apart: vs GitHub Copilot/Cursor: multi-agent DevOps assistant from Ant Group with repository-level code analysis, knowledge graphs, and sandboxed execution — designed for enterprise private deployment
Best for: DevOps teams needing AI-assisted code analysis and generation; Enterprise teams wanting private, self-hosted coding assistant with RAG
6. DB-GPT
open-source agentic AI data assistant for the next generation of AI + Data products.
What sets it apart: Full-stack AI data assistant combining autonomous SQL generation, sandboxed code execution, and reusable skills in a single platform — not just a chatbot
Best for: Data teams needing natural language database querying; Organizations wanting AI-powered data analysis assistants; Teams building data-driven agent workflows
7. 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
8. OpenAI Developers Responses API reference
OpenAPI specification for the OpenAI API
What sets it apart: The canonical machine-readable OpenAI API specification — the single source of truth for building typed clients, mock servers, and API tooling around OpenAI's services
Best for: SDK authors generating OpenAI client libraries; Developers building OpenAI API integrations with type safety