Interactive knowledge graph visualizer — Sigma.js WebGL renderer with ForceAtlas2/Tree/Circle layouts for exploring multi-project codebase graphs at scale.
76,539 nodes · 269,962 edges — merged across 67 projects from three data sources.
Like DeepWiki, but deeper. DeepWiki helps you understand code. brain-nexus lets you analyze it — because a knowledge graph tracks every relationship, not just descriptions.
TL;DR: Drop in a knowledge-graph.json and get instant graph exploration across 76,539 nodes · 269,962 edges merged across 67 projects — plus a built-in AI assistant (Loisekk AI) and rebranded Cypher console (Synapse Query).
Built on GitNexus — the zero-server code intelligence engine — with custom data sources (Galaxy + Graphify) and unique branding.
| 🎨 Sigma.js WebGL rendering — smooth 60fps at scale | 🔍 ⌘K instant search — type-ahead across all nodes |
| 🗺️ 3 view modes — Force-directed (FA2), Tree, Circles | 📂 Left sidebar — file tree + node/edge type + depth filters |
| 🤖 Loisekk AI chat — LangChain agent with 7 Graph RAG tools | 🔬 Node inspection — click for details, neighbors, references |
| ⚡ Synapse Query console — rebranded Cypher with examples | 🎨 Community clustering — Leiden + coloring |
| 🌙 Dark theme — responsive, collapsible panels, mobile-ready | 🔌 Local backend support — auto-connect to gitnexus serve |
| Static JSON | Local Backend | |
|---|---|---|
| What | Built-in knowledge-graph.json with 76K+ nodes |
Connect to gitnexus serve running locally |
| For | Immediate exploration, demos, pre-built graphs | Live analysis of your own repos |
| Scale | 76,539 nodes · 269,962 edges (pre-merged) | Full repos, any size |
| Setup | npm install && npm run dev |
npx gitnexus serve + open UI |
| Privacy | Everything in-browser, no server | Everything local, no network |
The bundled graph aggregates three sources into one unified knowledge base:
| Source | Nodes | What it contains |
|---|---|---|
| GitNexus (code intelligence) | 45,077 | Functions, classes, imports, call graphs, file hierarchies from 67 repos |
| Galaxy (custom) | 28,943 | Project metadata, file relationships, concepts, keywords, cross-project structure |
| Graphify (custom) | 2,519 | Session memories, conversations, development rationale, context |
The Galaxy and Graphify datasets are your own custom additions — they don't exist in upstream GitNexus.
# Clone
git clone https://github.com/loisekk/brain-nexus.git
cd brain-nexus
# Install & run
npm install
npm run devOpens at http://localhost:5173 with the full knowledge graph pre-loaded.
# Via URL param
http://localhost:5173/?data=https://example.com/your-graph.json
# Or connect to local GitNexus backend
npx gitnexus serve # in any indexed repo
# UI auto-detects the server{
"nodes": [
{ "id": "...", "label": "main.py", "type": "file", "project": "my-project", "source_file": "..." }
],
"edges": [
{ "source": "...", "target": "...", "relation": "imports", "confidence": "EXTRACTED" }
]
}The built-in AI assistant — rebranded from GitNexus's "Nexus AI" — has access to all three data sources:
- Code intelligence – functions, classes, imports, call graphs
- Project metadata – file relationships, concepts, cross-project connections
- Session context – development history, decisions, rationale
Powered by LangChain with 7 Graph RAG tools. Supports any OpenAI-compatible provider — configure your API key in Settings (OpenAI, Anthropic, Gemini, DeepSeek, Ollama, and more).
"Which projects use FastAPI?"
"Show me all ML projects and their dependencies"
"What functions call pandas.read_csv?"
"Show the architecture of the worldmonitor project"
"Find connections between worldmonitor and opencode-second-brain"
"What's the most complex project in my codebase?"
Rebranded Cypher console — same graph query syntax, Loisekk branding. Run structured queries against the knowledge graph:
MATCH (c:Community {heuristicLabel: 'Authentication'})<-[:CodeRelation {type: 'MEMBER_OF'}]-(fn)
MATCH (caller)-[r:CodeRelation {type: 'CALLS'}]->(fn)
WHERE r.confidence > 0.8
RETURN caller.name, fn.name, r.confidence
ORDER BY r.confidence DESCbrain-nexus is a browser-first knowledge graph visualizer built on the GitNexus engine. The frontend handles everything client-side:
- Load — reads JSON knowledge graph from file, URL param, or local backend
- Render — Sigma.js WebGL renders 76K+ nodes at 60fps
- Explore — three layout modes, ⌘K search, file tree, filters
- Analyze — click nodes, inspect neighbors, traverse relationships
- Chat — Loisekk AI agent with Graph RAG across all data sources
- Query — Synapse Query console for custom graph exploration
Frontend (brain-nexus) Backend (FastAPI — planned)
┌─────────────────────┐ ┌──────────────────┐
│ Sigma.js + React 19 │────────▶ /api/chat |
│ ⌘K Search │ │ /api/synapse │
│ 3 Layout Modes │ │ /api/search │
│ File Tree │ │ /api/node/:id │
│ Synapse Query FAB │ │ /api/embed │
│ Loisekk AI Chat │────────▶ Loisekk Agent │
└─────────────────────┘ └──────────────────┘
The FastAPI backend + Neo4j integration are not yet built — currently everything runs in-browser. See roadmap.
- Rebrand GitNexus → brain-nexus, Nexus AI → Loisekk AI, Cypher → Synapse Query
- English-only localization (removed zh-CN)
- Auto-load
knowledge-graph.jsonon startup - Fix heartbeat SSE to avoid false "connection lost" errors
- Custom Galaxy dataset (28,943 nodes) — project metadata
- Custom Graphify dataset (2,519 nodes) — session context
- FastAPI scaffold with routes: chat, synapse, search, node, stats
- Neo4j database: import all 76K nodes + 270K edges
- Full-text and vector indexes
- Server-side LangChain agent with persistent cross-session memory
- Custom tools: synapse_query, semantic_search, get_node, find_path
- Custom system prompt with all 67 project context
- Pre-compute embeddings for all 76K nodes via sentence-transformers
- Vector index in Neo4j for semantic search across all projects
- Synapse Query autocomplete + syntax highlighting
- Mobile responsive polish
- Vercel deployment + GitHub Actions CI/CD
- API documentation (Swagger)
| Layer | Tech |
|---|---|
| Rendering | Sigma.js v3 + Graphology (WebGL) |
| Frontend | React 19, TypeScript 5, Vite 8, Tailwind v4 |
| AI Agent | LangChain ReAct (client-side, 7 tools) |
| LLM Providers | OpenAI, Anthropic, Gemini, DeepSeek, Ollama, Azure, OpenRouter, MiniMax, GLM |
| Clustering | Graphology (Leiden algorithm) |
| Search | GitNexus hybrid (BM25 + semantic + RRF) |
| State | React Context + custom hooks |
| Testing | Vitest + Playwright E2E |
| i18n | English only |
| Planned DB | Neo4j (Cypher/Synapse compatible) |
| Component | Source |
|---|---|
| Sigma.js renderer, 3 layouts, file tree, filters | GitNexus (upstream) |
| LangChain agent, 7 Graph RAG tools, LLM providers | GitNexus (upstream) |
| Galaxy data (28,943 nodes across 67 projects) | Custom |
| Graphify data (2,519 nodes of session context) | Custom |
| brain-nexus branding, Loisekk AI, Synapse Query | Custom |
| English-only locale, auto-load, heartbeat fix | Custom |
| FastAPI backend + Neo4j | Planned |
- Static mode: Everything runs in your browser. No code uploaded. No server needed.
- Backend mode: Connect to a local
gitnexus serveinstance. All data stays on your machine. - API keys stored in
localStorageonly (never sent to any server other than the LLM provider you configure).
Visualizer engine built on GitNexus by Abhigyan Patwari. Sigma.js graph rendering, ForceAtlas2 layout, file tree, Graph RAG agent, and Cypher console are all from the GitNexus project.
Custom data sources (Galaxy, Graphify) and branding (brain-nexus, Loisekk AI, Synapse Query) by Yash Brahmankar.
| Library | Purpose |
|---|---|
| Sigma.js | WebGL graph rendering |
| Graphology | Graph data structures + algorithms |
| LangChain | AI agent framework |
| React | UI framework |
| Tailwind CSS | Styling |
| Vite | Build tool |
| Tree-sitter | AST parsing (via GitNexus) |