Opal fuses handwritten notes, linked markdown, and spaced repetition into a single app. Draw diagrams with Apple Pencil, connect ideas with wikilinks, and let the algorithm schedule your reviews.
A knowledge graph represents concepts as nodes and relationships as edges. In personal knowledge management, graphs emerge organically from wikilinks between notes, creating a web of interconnected ideas.
Each note becomes a node with properties: kind, title, and stability. Edges capture the strength and type of connection between concepts, enabling Spaced Repetition Systems to build adaptive study paths.
Backlinks surface implicit connections. When you reference a concept in multiple notes, Opal surfaces those relationships automatically, revealing patterns you might otherwise miss.
Four capabilities woven into one calm, focused interface.
Three actions. One seamless loop.
Because context switching kills retention. Opal brings everything into one place.
| Opal | Obsidian + Anki | GoodNotes | Notion | |
|---|---|---|---|---|
| Markdown editor | ✓ | ✓ | — | ~ |
| Apple Pencil handwriting | ✓ | — | ✓ | — |
| Spaced repetition | ✓ | ~ | — | — |
| Knowledge graph | ✓ | ✓ | — | — |
| Ink inside markdown | ✓ | — | — | — |
| Cards from notes | ✓ | ~ | — | — |
| Local-first / offline | ✓ | ✓ | ✓ | — |
| Single app | ✓ | — | — | — |
We're recruiting for our closed beta. Free while we're building. Your feedback shapes the product.