Flexnote vs Heptabase: Where Two Card-Based Whiteboards Differ (2026)

If you're looking for a "cards + infinite whiteboard" visual note-taking tool, both Heptabase and Flexnote will likely show up — and if you're specifically searching for the best Heptabase alternatives, Flexnote is one of the names that comes up most. They look similar — cards hold the content, and an endlessly pannable canvas lets you arrange ideas spatially — but they optimize for different things. This article won't crown an absolute winner; it lays out the key differences so you can choose based on your own needs.

1. Positioning: both built for deep learning and research

Their target audiences overlap heavily — both are built for deep learning and research, helping you connect scattered cards into a system on the whiteboard for literature reviews, course notes, and long-running research. Heptabase has a mature toolset and an active community, and is deeply polished around "thinking complex topics through."

Flexnote is built for the same deep-learning and research use, but takes a different path: it's local-first, leans harder on data privacy and ownership, and pairs that with a self-built high-performance canvas, broader annotation, and a one-time-purchase option — a lighter, more self-directed take on the same "research whiteboard."

2. Canvas and performance: same shape, different foundation

The base unit in both is the card, and both support Markdown, bidirectional links, and free arrangement and linking on a whiteboard. But the rendering foundation is a key difference: Heptabase renders the canvas with DOM-based web technology, while Flexnote uses a self-built high-performance Canvas engine. When a board grows to hundreds of cards with heavy zooming and dragging, a Canvas approach usually stays smoother.

3. Annotation: more than PDF

Research lives on annotating your source material, and here the gap is clear. Flexnote can annotate cards, PDFs, video (including YouTube), and audio — whether your material is a paper, a course video, or a podcast, you can highlight and take notes right on the source and link back to the canvas. Heptabase currently supports PDF annotation only.

4. AI: not just answers, but edits to your library and board

AI is no longer an advantage unique to Heptabase. Flexnote AI is available to Pro members through Knowledge Ask, Agent, and card AI Actions. Ask searches the local knowledge base, accepts @-mentioned cards as context, and returns answers with citations. Agent can go further: create and edit cards, organize tags and todos, and group, connect, or lay out content on the current whiteboard.

Flexnote uses BYOK (bring your own API key). You can choose OpenAI, DeepSeek, Tongyi Qianwen, Kimi, Zhipu GLM, or a custom compatible endpoint instead of being locked to one model provider. Smart indexing adds semantic search and image OCR, while the card menu offers quick actions for summarizing, translating, generating mind maps, and custom prompts. Together with multimedia annotation, AI can answer questions about PDFs and videos, save results as cards, and keep organizing them on the board.

5. Local-first, privacy, and publishing

This is where the two differ most in spirit.

• Heptabase: requires an account and online login to use, with the account tied to the cloud; data exports to Markdown and JSON, but a copy is kept on servers and there is currently no end-to-end encryption.
• Flexnote: local-first — you can use it locally without a mandatory online login, and data stays in your hands by default. For cross-device sharing it syncs through third-party cloud storage like Baidu Cloud, OneDrive, S3, and WebDAV, so you decide where your data lives.

Local-first doesn't mean closed off: Flexnote can publish a whiteboard to the web, generating a link anyone can open in a browser, and supports exporting to PDF and other formats — keeping data ownership without giving up sharing.

6. Platforms and collaboration

Heptabase offers Mac, Windows, Linux, iOS, Android, and Web, plus collaborator invites. Flexnote offers Windows / macOS desktop and mobile apps for capturing and reviewing on the go.

7. Pricing

For many people this is the deciding factor, and it differs a lot.

• Heptabase: subscription only, no permanent free tier, with a 7-day trial. Pro is about $8.99/mo billed yearly; more AI credits come via Premium ($17.99/mo) or Premium+ ($53.99/mo).
• Flexnote: has a permanent free tier (100 cards, local storage, single device); paid plans are Pro at $29/quarter or $49/year, plus a $149 one-time lifetime license.

8. At a glance

9. How to choose

Both are built for deep learning and research, and both now bring AI into the knowledge workflow. If you value a mature ecosystem, hosted AI credits, and full cross-platform collaboration, and don't mind an ongoing subscription, Heptabase is a proven, reliable choice.

If you value canvas performance (large boards staying smooth), need full annotation across cards, PDFs, video, and audio, care about local-first data privacy, want to use your own model key for cited answers and let an Agent organize the board directly, want to sync across devices flexibly via third-party cloud storage, and prefer starting free or buying once, then Flexnote fits your workflow better and costs less over time.

The two aren't mutually exclusive — they represent two reasonable trade-offs within the same "whiteboard notes" category. The best move is to run your real note-taking scenario through each one's free tier or trial.