Kastor
Build and coordinate powerful multi-agent AI systems with ease.
Quick answer
Kastor — Build and coordinate powerful multi-agent AI systems with ease. It's free. Best for building multi-step research assistants that delegate subtasks to specialized sub-agents.
Kastor is a free, open-source framework designed to help developers build, orchestrate, and coordinate multi-agent AI systems from the ground up. It provides the structural backbone that engineers and AI researchers need to connect multiple autonomous agents, enabling them to collaborate, share context, and complete complex tasks that a single agent could not handle alone. Kastor is best suited for developers who want full control over their AI pipelines without vendor lock-in or subscription costs, making it a compelling choice for startups, independent researchers, and enterprise teams experimenting with agentic workflows. The framework emphasizes composability and extensibility, allowing teams to plug in their preferred language models, memory solutions, and tool integrations. Whether you are prototyping a customer support automation system, building a research assistant that spawns sub-agents, or coordinating long-horizon planning tasks, Kastor provides the infrastructure to get there quickly and transparently.
Key features
- Multi-agent orchestration framework for coordinating multiple AI agents simultaneously
- Open-source codebase with full transparency and community-driven development
- Extensible architecture supporting custom LLM backends and tool integrations
- Agent communication and context-sharing protocols for collaborative task execution
Pros & cons
- +Completely free and open-source with no licensing fees or usage limits
- +Gives developers full control over agent logic, memory, and integrations
- +Active open-source community enables rapid iteration and community-contributed extensions
- −Requires developer expertise to set up and configure compared to managed platforms
- −Documentation and support may be limited compared to commercial multi-agent frameworks
Pricing
Fully free and open-source
N/A
Self-hosted, no cost
Who is it for
- →Building multi-step research assistants that delegate subtasks to specialized sub-agents
- →Automating complex workflows where multiple AI agents must collaborate and hand off results
- →Prototyping agentic pipelines for startups or research teams without incurring API or platform costs
Frequently asked questions
Is Kastor free?
Yes, Kastor is completely free and open-source. You can download, modify, and use the framework at no cost under its open-source license.
What is Kastor best used for?
Kastor is best used for building and coordinating multi-agent AI systems, particularly for developers who need to orchestrate several autonomous agents working together on complex, multi-step tasks.
What are the best alternatives to Kastor?
Popular alternatives include LangGraph, AutoGen by Microsoft, CrewAI, and LlamaIndex Workflows. Each offers multi-agent coordination with varying levels of abstraction and managed services.
Is Kastor safe to use?
As an open-source framework, Kastor's code is publicly auditable, which allows developers to inspect it for security issues. Safety ultimately depends on how you configure your agents and which external APIs or models you connect.
How much does Kastor cost?
Kastor is free to use. There are no subscription fees, usage limits, or enterprise tiers. The only potential costs come from the external LLM APIs or infrastructure you choose to run it on.
Reviews
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