Kastor vs onBeacon (2026)
A side-by-side comparison of Kastor and onBeacon on pricing, features, and fit, so you can decide which is right for you.
Quick answer
Kastor and onBeacon 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 onBeacon if you need identifying and prioritizing high-impact growth experiments for a saas product — its edge is provides round-the-clock growth intelligence without requiring a full-time hire. Kastor starts at Free; onBeacon starts at approximately $49/month for full AI PM 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
- 24/7 AI-driven growth analysis and recommendations
- Automated prioritization of product growth initiatives
- User behavior insights and friction point detection
- Continuous monitoring with proactive growth alerts
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
- Provides round-the-clock growth intelligence without requiring a full-time hire
- Bridges the gap between raw data and clear product decisions
- Helps small and mid-sized teams move faster with AI-backed prioritization
- May require integration setup that takes time for non-technical users
- AI recommendations may need human validation before acting on high-stakes decisions
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 onBeacon if
you mainly need to identifying and prioritizing high-impact growth experiments for a saas product. Its edge: provides round-the-clock growth intelligence without requiring a full-time hire.
Frequently asked questions
Is Kastor better than onBeacon?
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. onBeacon is stronger for identifying and prioritizing high-impact growth experiments for a saas product, with an edge in provides round-the-clock growth intelligence without requiring a full-time hire. Pick based on your main task.
Which is cheaper, Kastor or onBeacon?
Kastor starts at Free and onBeacon starts at approximately $49/month for full AI PM features. Free tier: Kastor — Fully free and open-source; onBeacon — Limited access with basic growth recommendations.
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 onBeacon best for?
onBeacon is best for identifying and prioritizing high-impact growth experiments for a saas product, reducing churn by detecting user drop-off points and recommending fixes, helping early-stage startups operate with a full-time pm-level growth strategy on a lean budget.
Do Kastor and onBeacon have free plans?
Kastor: Fully free and open-source. onBeacon: Limited access with basic growth recommendations. Check each tool's pricing page for current limits, as plans change.