Kastor vs Zaro (2026)
A side-by-side comparison of Kastor and Zaro on pricing, features, and fit, so you can decide which is right for you.
Quick answer
Kastor and Zaro are both strong choices, but they fit different needs. Choose Kastor if you mainly need building multi-step research assistants that delegate subtasks to specialized sub-agents — its edge is completely free and open-source with no licensing fees or usage limits. Choose Zaro if you need building an internal knowledge assistant from company documents — its edge is extremely low barrier to entry, one prompt can launch a working agent. Kastor starts at Free; Zaro starts at $19/month for expanded agent capacity and features.
Features compared
- 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
- Single-prompt agent creation from personal or team context
- Custom app building without writing code
- Context-aware AI that learns from your documents and workflows
- Supports multiple agent types including assistants, automations, and chatbots
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
- Extremely low barrier to entry, one prompt can launch a working agent
- Context-first approach makes agents more relevant and accurate
- Flexible enough for both personal users and business teams
- Limited public documentation makes it harder to evaluate advanced capabilities
- As a newer platform, integrations and third-party connectors may still be limited
The verdict
Choose Kastor if
you mainly need to building multi-step research assistants that delegate subtasks to specialized sub-agents. Its edge: completely free and open-source with no licensing fees or usage limits.
Choose Zaro if
you mainly need to building an internal knowledge assistant from company documents. Its edge: extremely low barrier to entry, one prompt can launch a working agent.
Frequently asked questions
Is Kastor better than Zaro?
Neither is universally better. Kastor is stronger for building multi-step research assistants that delegate subtasks to specialized sub-agents, with an edge in completely free and open-source with no licensing fees or usage limits. Zaro is stronger for building an internal knowledge assistant from company documents, with an edge in extremely low barrier to entry, one prompt can launch a working agent. Pick based on your main task.
Which is cheaper, Kastor or Zaro?
Kastor starts at Free and Zaro starts at $19/month for expanded agent capacity and features. Free tier: Kastor — Fully free and open-source; Zaro — Free tier available with limited agents and context capacity.
What is Kastor best for?
Kastor is best 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.
What is Zaro best for?
Zaro is best for building an internal knowledge assistant from company documents, automating repetitive research or data-gathering tasks, creating customer-facing chatbots grounded in product documentation.
Do Kastor and Zaro have free plans?
Kastor: Fully free and open-source. Zaro: Free tier available with limited agents and context capacity. Check each tool's pricing page for current limits, as plans change.