What is OpenBoard?

OpenBoard is an open-source, local-first visual whiteboard application engineered for software developers, system architects, and autonomous AI coding agents. It pairs an infinite vector drawing canvas powered by tldraw with an embedded SQLite persistence engine and a native 13-tool Model Context Protocol (MCP) server.

Unlike traditional cloud SaaS whiteboards (Miro, Lucidchart, FigJam) that require mandatory cloud accounts, charge monthly per-seat fees, and transmit confidential architecture diagrams to external cloud servers, OpenBoard operates 100% locally on your machine.

Why We Built OpenBoard

Modern software engineering teams face two critical problems when diagramming system architecture:

Confidentiality & Cloud Leaks: Technical architecture diagrams contain your most sensitive intellectual property—database schemas, VPC network boundaries, auth token flows, and microservice topologies. Uploading these to multi-tenant cloud SaaS creates unacceptable compliance and security vulnerabilities.
AI Assistants are Text-Blind: Terminal AI assistants like Claude Code, Cursor, Codex, and OpenCode can write thousands of lines of code, but they cannot natively see, sketch, or iterate on visual diagrams without high-level semantic tools.

OpenBoard bridges this divide by providing a fast, zero-telemetry local canvas that both humans and AI agents can manipulate concurrently in real time.

The Three Core Pillars

100% Local SQLite Persistence: All boards, shapes, connectors, and versions reside solely in ~/.openboard/openboard.db with Write-Ahead Logging (WAL) enabled for sub-millisecond atomic transactions.
13 Semantic MCP Tools: High-level JSON-RPC 2.0 tools that allow AI coding agents to create shapes, connect nodes with labeled arrows, group services, and inspect canvas hierarchy deterministically.
Real-Time Live SSE Sync: When your AI agent modifies a diagram in the terminal, mutations stream immediately into your browser tab over Server-Sent Events with sub-10ms latency.