OpenCrab is an ontology-centered knowledge platform designed for the AI agent era. It enables experts, researchers, and AI builders to transform scattered documents, notes, workflows, and domain expertise into structured, evidence-backed 'ontology packs.' These packs can be searched, shared, and queried by AI agents using Graph RAG and Model Context Protocol (MCP), grounding AI workflows in verifiable, high-quality knowledge graphs.
An ontology-centered Graph RAG platform that structures documents into reusable AI knowledge packs.
- Creating personal, evidence-backed knowledge graphs from research papers and analyst reports for grounded QA.
- Publishing and selling professional, domain-specific ontology packs on the OpenCrab Marketplace.
- Grounding custom AI agents (e.g., Claude Code, GPT) with unified enterprise knowledge endpoints.
- Synthesizing structured research notes for branding, product strategy, and customer sentiment analysis.
- To use OpenCrab
- first ingest unstructured data sources like PDFs
- HWP files
- URLs
- Notion pages
- or GitHub repositories. The platform extracts entities
- concepts
- claims
- and relations
- structuring them into a 9-space MetaOntology. Once structured
- you can query this knowledge graph using Graph RAG
- MCP clients

AI-powered food nutrition and dietary therapy platform.


AI solutions for complex data, transforming it into actionable insights.


Persistent context layer for AI agents to connect and reason across business tools.


A global patent search and analysis platform with comprehensive IP services.


AI-driven financial knowledge graph for real-time market insights.


Visual tool for researchers to find and explore relevant academic papers.


Free AI concept map maker for visualizing ideas and knowledge.


Learn Anything Joyfully - From the Best Sources, Faster


AI-powered research web app for building scientific knowledge graphs.







