Notes that link
Each note is a node. A [[wikilink]] draws an edge to another note, and every note shows its backlinks — who points here — so context finds you.
Knowledge graphs · Second brain
Connect what you know. Build your second brain.
A knowledge graph stores ideas the way your mind does — as things and the links between them. Write notes, link them with [[double brackets]], let AI find the people, tools and concepts inside, then explore it all as a living graph and ask it questions.
What is a knowledge graph?
Folders force every idea into one place. A graph lets an idea live in many contexts at once — and shows you connections you did not plan.
Entities and relations
Beneath your notes sits a graph of things: people, organisations, tools, models, concepts — joined by relations like “developed”, “uses” or “part of”.
Search by meaning
Embeddings turn each note into a vector, so you can find notes by what they mean — not just the words they share — and discover related notes automatically.
How your second brain works here
Write and link
Markdown notes with [[links]] and #tags. Type [[ to link any note; links to notes that do not exist yet are one click from being created.
Capture anything
Save a web page as a clean note, import an Obsidian vault of Markdown files, or keep a chat answer or news story.
Extract with AI
One click pulls out people, organisations, tools, models and concepts, and how they relate — using the model you choose.
Explore and ask
Wander the interactive graph, then ask questions and get answers grounded in your own notes, with citations.
Tools for building knowledge graphs
From personal note apps to graph databases and GraphRAG frameworks — the products people use to turn information into connected knowledge.
Directory facts come from each vendor's own website and GitHub. Pricing appears only where we checked the vendor's pricing page.
Second-brain and note apps
Personal knowledge management: linked notes, backlinks, graph views and AI assistants for your own ideas.
Graph databases and ontologies
Where knowledge graphs live at scale: property graphs, RDF stores, ontology editors and web-scale graphs.
GraphRAG and AI memory
Frameworks that build graphs from documents with LLMs, and give agents a long-term, connected memory.
Your ideas deserve better than a pile of files.
Start with one note. Link it to the next. Watch the graph grow.