Visual mapping versus AI-readable memory
Heptabase is a visual knowledge tool. You place note cards on infinite whiteboards and arrange them spatially to map how ideas connect, alongside a journal, tags, and a card library. If you think visually, that canvas is a genuinely different and powerful way to work.
Hjarni is built around a different goal: making your notes something AI can read and write. It is a knowledge base of plain Markdown notes with an official MCP server, so assistants work from the same context across conversations. The shape is a clean note store, not a canvas.
Two official MCPs with different shapes
Its official hosted MCP lets external assistants search, read, create, and edit cards and journal entries. See Heptabase’s MCP tool documentation for the supported operations.
Hjarni's MCP is the core of the product rather than a feature beside the canvas. An assistant can search your notes, open one, update it in place, and file new notes into folders, with per-folder instructions steering how it writes. Choose between a folder-based Markdown workflow and a visual card-and-whiteboard workflow; both let assistants edit existing content.
If you think spatially and want whiteboards, Heptabase is excellent. If you prefer Markdown notes organized in folders, Hjarni is a strong fit.
Built-in AI and external assistants
Heptabase offers AI chat inside the app and connects external assistants through MCP. Its plan documentation also describes personal provider keys and supported Codex sign-in for its AI agent. These options have different billing and feature rules; an in-app credit allowance is not evidence that external MCP access has the same limit.
Hjarni does not bundle a model. You connect Claude, ChatGPT, Codex, Cursor, or any MCP client, and the same notes serve every assistant. The knowledge does not live inside one product's AI.
Shared content and personal workspaces
Heptabase can share individual cards and whiteboards with collaborators. Its limited free plan lets invited people edit shared content, while a paid personal workspace adds the card library, journal, tags, and AI features. Hjarni uses shared team folders and folder roles. Compare the permissions and devices your team needs rather than treating collaboration as exclusive to either product.
When Heptabase is the better fit
If you think spatially and want to organize and connect notes visually on whiteboards, Heptabase is a strong, distinctive choice. Its Markdown export is first-class too, so your data stays portable even though the workflow is visual.
When teams pick Hjarni instead
The case for Hjarni is Markdown as the note source format, nested folders, per-folder instructions, and shared team knowledge. Heptabase also lets external assistants maintain content, so write access alone is not a reason to switch.
Hjarni notes are plain Markdown you own, exportable as a ZIP anytime, hosted in the EU.