https://github.com/garuda8887/recall
Self-hosted spaced repetition calendar — SM-2 scheduling, forgetting curves, knowledge graph & dark mode. Privacy-first Anki alternative for visual learners.
https://github.com/garuda8887/recall
anki-alternative calendar dark-mode education forgetting-curve javascript knowledge-graph nodejs productivity pwa self-hosted sm2 spaced-repetition sqlite study-planner
Last synced: 25 days ago
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Self-hosted spaced repetition calendar — SM-2 scheduling, forgetting curves, knowledge graph & dark mode. Privacy-first Anki alternative for visual learners.
- Host: GitHub
- URL: https://github.com/garuda8887/recall
- Owner: Garuda8887
- License: mit
- Created: 2026-05-26T12:09:50.000Z (30 days ago)
- Default Branch: master
- Last Pushed: 2026-05-26T12:48:44.000Z (30 days ago)
- Last Synced: 2026-05-26T14:22:15.687Z (30 days ago)
- Topics: anki-alternative, calendar, dark-mode, education, forgetting-curve, javascript, knowledge-graph, nodejs, productivity, pwa, self-hosted, sm2, spaced-repetition, sqlite, study-planner
- Language: HTML
- Size: 2.95 MB
- Stars: 0
- Watchers: 0
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- Contributing: CONTRIBUTING.md
- License: LICENSE
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README
# Recall — Spaced Repetition Calendar
[](LICENSE)
[](https://nodejs.org/)
[]()
[]()
> Anki's algorithm. A calendar you actually want to open.
Anki is effective but its interface is stuck in 2004. Recall gives you the same scientifically-proven SM-2 spaced repetition wrapped in a month-view calendar that makes your entire study schedule visible at a glance. Self-hosted, no sync fees, no card decks — log what you studied and show up when it tells you to.
If Recall is useful to you, consider giving it a ⭐ — it helps others find it.
---
## Features
| Feature | Description |
|---|---|
| **SM-2 Spaced Repetition** | Reviews are scheduled at scientifically-optimal intervals (default: +1, +3, +7, +14, +30 days). Confidence ratings adapt future intervals via ease-factor. |
| **Calendar View** | Month-view calendar with colour-coded chips: studied sessions, review 1–5, overdue indicators. |
| **Confidence Ratings** | Mark reviews with Blank / Hard / Okay / Good / Perfect — the SM-2 algorithm reschedules the next review accordingly. |
| **Forgetting Curve** | Per-session exponential decay chart showing memory retention over time with study and upcoming review markers. |
| **Recurring Sessions** | Schedule a topic to auto-recur weekly or at a fixed interval — catch-up instances are created automatically on login. |
| **Drag-and-Drop Reschedule** | Drag undone review chips to any other calendar day to reschedule them. |
| **Subject Filter** | Filter the calendar by subject (Biology, Languages, Maths…) with one click. |
| **Tags** | Add free-form tags to sessions; filter the calendar by tag from the tag bar. |
| **Full-Text Search** | Instant search across topic, notes, subject and tags with match count. |
| **Second Brain Links** | Connect sessions with typed relations — *Builds on*, *Prerequisite of*, *Related to*, *See also* — displayed inline in the day modal. |
| **Knowledge Graph** | Obsidian-style force-directed graph of all linked sessions with pan, zoom, draggable nodes, and per-subject dimming. |
| **Stats & Heatmap** | Activity heatmap (last 13 weeks), per-subject retention bars with overdue count, and per-topic retention list. |
| **Dark Mode** | Toggle dark mode — the calendar, modals, and knowledge graph all adapt. |
| **Custom Intervals** | Set your own review intervals (e.g. 1 / 7 / 21 / 60 / 120 days). Changes apply to new sessions going forward. |
| **JWT Auth** | Full registration and login; all data is isolated per user. |
| **PWA** | Installable as a native-feeling app on iOS and Android — works offline, home screen icon, no app store required. |
---
## Screenshots
Populated calendar — studied chips in subject colour, review chips in red → blue gradient.
Confidence rating — rate recall after each review; SM-2 reschedules the next date.
Forgetting curve — per-session exponential decay chart with past and upcoming review markers.
Knowledge graph — Obsidian-style force-directed graph of all linked sessions.
Dark mode — full dark palette across the calendar, modals, and graph.
Stats & heatmap — 13-week activity heatmap and per-subject retention bars.
More screenshots
### Add Study Session
*Log a new topic with subject, notes, tags, and an optional weekly or interval-based recurrence rule.*
### Full-text search
*Live search filters the calendar to matching sessions. Matches topics, notes, subject, and tags simultaneously.*
### Subject filter
*One-click subject pill hides all other subjects. Physics selected here — only Newton's Laws and Projectile Motion shown.*
### Day modal — session details, tags & links
*Click any day to see all sessions and reviews. Shows tags, second-brain links, forgetting-curve button, and edit/delete controls.*
### Second brain — link sessions
*Link any two sessions with a typed relationship. Choose the relation type and target session — click Save Link to persist.*
### Knowledge graph — subject focus
*Click a subject pill in the graph toolbar to dim non-matching nodes — isolates a discipline's knowledge cluster at a glance.*
### Drag-and-drop reschedule
*Drag any undone review chip to a new calendar day to reschedule it. The server persists the new date immediately.*
### Settings — custom intervals
*Override the default SM-2 intervals with any values you prefer. Preview dates update live as you type.*
---
## Getting Started
### Prerequisites
- [Node.js](https://nodejs.org/) 18 or later
- npm
### Install & run
```bash
git clone https://github.com/Garuda8887/recall.git
cd recall
npm install
node server.js
```
Open **http://localhost:3000** in your browser, register an account, and start logging sessions.
### Environment variables
| Variable | Default | Description |
|---|---|---|
| `PORT` | `3000` | HTTP port |
| `JWT_SECRET` | `recall-dev-secret-please-change-in-production` | **Change this in production** |
```bash
JWT_SECRET=my-super-secret-key PORT=8080 node server.js
```
### Install as an app (PWA)
Recall is a fully installable Progressive Web App — no app store required.
| Platform | How to install |
|---|---|
| **iOS / iPadOS** | Open in Safari → Share → **Add to Home Screen** |
| **Android** | Open in Chrome → three-dot menu → **Add to Home Screen** (or accept the install prompt) |
| **Desktop (Chrome / Edge)** | Click the install icon in the address bar |
Once installed it launches fullscreen with its own icon, just like a native app. It also works offline — the app shell is cached locally so the UI loads instantly even without a connection (data syncs when you're back online).
**Updating:** just `git pull` on your server. The service worker detects the new version and refreshes automatically on next open — no reinstall needed.
---
## How it works
### SM-2 algorithm
After each review you rate your recall from 1 (blank) to 5 (perfect). SM-2 uses that score to grow or shrink the next interval — ace it repeatedly and reviews get pushed further out; struggle and it resets to the next day. The default schedule after a new session is **+1 · +3 · +7 · +14 · +30 days**, fully customisable in Settings.
### Recurring sessions
Set a session to recur *every Tuesday* or *every N days*. Any missed instances since the last login are auto-created (capped at 14 catch-ups per series).
---
## Tech stack
| Layer | Technology |
|---|---|
| Server | Node.js + Express |
| Database | SQLite via `better-sqlite3` (zero-config, single file) |
| Auth | JWT (`jsonwebtoken`) + bcrypt |
| Frontend | Vanilla HTML/CSS/JS — single-file SPA (`public/index.html`) |
| Graph | Custom force-directed simulation (Coulomb repulsion + Hooke springs + gravity) rendered in SVG |
---
## API reference
All session routes require `Authorization: Bearer `.
| Method | Path | Description |
|---|---|---|
| `POST` | `/api/auth/register` | Register `{ email, password }` |
| `POST` | `/api/auth/login` | Login → returns JWT |
| `GET` | `/api/auth/me` | Verify token |
| `GET` | `/api/sessions` | List all sessions (auto-creates due recurrences) |
| `POST` | `/api/sessions` | Create a session |
| `PUT` | `/api/sessions/:id` | Update topic / subject / notes / tags |
| `DELETE` | `/api/sessions/:id` | Delete session and its links |
| `PATCH` | `/api/sessions/:id/reviews/:index` | Mark done (with confidence + SM-2), undo, or reschedule (`newDate`) |
| `GET` | `/api/links` | List knowledge-graph links |
| `POST` | `/api/links` | Create a link `{ fromId, toId, relation }` |
| `DELETE` | `/api/links/:id` | Remove a link |
| `GET` | `/api/settings` | Get custom intervals |
| `PUT` | `/api/settings` | Save custom intervals |
---
## License
MIT © [Garuda8887](https://github.com/Garuda8887)
Free to use, copy, modify and distribute. The copyright notice above must be included in all copies or substantial portions of the software — if you build on this, you must credit the original author.
---
*Built with ❤️ as a self-hosted alternative to Anki, optimised for visual learners who think in calendars.*