Chaptera Reference Manual

Supported Formats

Key Capabilities

Subscription Tiers

Adding Books

Books can be added to your library in two ways:

• Drag and drop — drag one or more files directly onto the library page drop zone.
• Browse dialog — click the Upload Book button and select files through the file picker.

View Modes

Sorting

Search

Press Cmd+K (macOS) or Ctrl+K (Windows/Linux) anywhere in the library to open the quick search palette. You can also click the search icon in the library toolbar.

• Searches title and author fields across your entire library.
• Results update in real time as you type.
• Select a result with arrow keys and press Enter to open the book.

Filter Tabs

Book Cards

In Grid and List views, each book card displays:

• Cover image (or auto-generated placeholder if none is available)
• Title and author
• Reading progress percentage with a visual progress bar
• Annotation count chips: notes count, highlights count, bookmarks count
• Format badge (EPUB or PDF)
• Context menu (three-dot icon) for quick actions: Open, Edit Metadata, Delete, Convert to EPUB

Edit Metadata

Open a book's context menu and select Edit Metadata to change:

• Title — free-text field
• Author — free-text field
• Cover image — upload a replacement image (JPG or PNG)
• Description — free-text synopsis, shown in library tooltips

Deleting Books

Select Delete from the book's context menu. A confirmation dialog will appear. Deletion permanently removes the book file, all associated annotations, reading progress, and AI-generated content.

Bulk Selection and Actions

• Click the checkbox that appears on hover in Grid view, or the row checkbox in Table view, to select individual books.
• Use Shift+click to select a range.
• The bulk-action toolbar appears at the bottom of the page when one or more books are selected.
• Bulk actions available: Add to Collection, Delete, Export Annotations.

PDF-to-EPUB Conversion

PDFs can be converted to reflowable EPUB format, unlocking all EPUB-exclusive reading modes and display settings.

Continue Reading Shelf

The top of the library page shows a Continue Reading shelf displaying your 3–5 most recently opened books with their current progress. Clicking a card reopens the book at your last saved position.

Standard Collections

Standard collections are manually managed folders. You decide which books belong to each one.

• Click New Collection in the left sidebar or via the Collections page header.
• Enter a name, choose an icon and colour, then save.
• Add books by dragging them onto the collection in the sidebar, or via the book's context menu → Add to Collection.
• A book can belong to multiple collections simultaneously.

Smart Collections

Smart collections automatically include books that match a set of filter rules. Rules are re-evaluated whenever your library changes.

Available Filter Rules

Multiple rules within a smart collection are combined with AND logic (all rules must match) or OR logic (any rule matches), selectable per collection.

Creating and Editing Collections

Colour and Icon Customisation

Each collection can have a custom colour (chosen from a palette of 12 colours) and an icon (chosen from a set of 30+ emoji/icon options such as 📚, 🔬, 🎭, ⭐). Colours appear in the sidebar indicator dot and as an accent on the collection's cover mosaic.

Hierarchical Collections

Collections can be nested to create parent/child hierarchies up to 3 levels deep. To create a sub-collection, drag an existing collection onto a parent, or use the Create inside… option in the ··· menu.

Navigation

Keyboard Shortcuts

Font Size Adjustment

Use the + and − buttons in the reader toolbar, or the keyboard shortcuts above. Font size can also be set precisely in the Display Settings panel (see Section 6). Changes apply instantly without losing your reading position.

Within-Book Search

Press Ctrl+F or click the search icon in the toolbar to open the find bar. Enter a search term to highlight all matches in the current chapter and display a result count. Use Enter to cycle through matches.

CFI-Based Deep Linking

Chaptera uses Canonical Fragment Identifiers (CFI) to encode precise positions within an EPUB. Every annotation, bookmark, and saved reading position is stored as a CFI string, enabling exact position restoration across sessions and devices — even after re-uploads.

Page Navigation

Zoom Controls

Text Selection and Highlighting

Click and drag to select text on any PDF page. A floating action toolbar appears above the selection with options to:

• Highlight — choose from 6 colours (yellow, green, blue, purple, red, orange)
• Add Note — attach a text note to the selection
• Copy — copy the selected text to clipboard
• Ask AI — open the AI Chat panel with the selected text as context
• Summarize — generate an instant summary of the selected passage

Within-PDF Search

Press Ctrl+F to open the search panel. Matches are highlighted across all pages and listed in the results panel. Options include whole-word matching and case-sensitive search.

Display Tab

Text Tab

Spacing Tab

Advanced Tab

1 — Normal Mode

Default mode. Renders text exactly as authored in the EPUB/PDF, applying only your Display Settings preferences (font, spacing, alignment). Best for general reading.

To activate: Select Normal from the reading mode dropdown in the toolbar.

2 — Bionic Reading

Bionic Reading bolds the leading portion of each word (the "fixation point"), training the eye to move faster across the line and allowing the brain to complete each word with less effort. Studies suggest this can increase reading speed by 20–30% for practised users.

To activate: Select Bionic from the reading mode dropdown.

3 — Dyslexia-Friendly Mode

Applies a suite of accessibility-focused typographic adjustments designed to reduce character confusion and improve reading flow for readers with dyslexia.

To activate: Select Dyslexia from the reading mode dropdown. Colour overlay can be toggled independently in the mode settings panel.

4 — Focus Mode

Focus Mode minimises all visual distractions. The sidebar, toolbar, and all UI chrome are hidden, leaving only the reading text centred on a clean background. A minimal floating bar at the top provides essential controls (exit, bookmark, font size).

5 — Speed Reading (RSVP)

Rapid Serial Visual Presentation displays one word (or short phrase) at a time in the centre of the screen at a configurable speed. This technique eliminates sub-vocalisation and backward eye movements, enabling reading speeds of 400–1000+ WPM for trained users.

Controls: Space to pause/resume; ← / → to rewind/advance by sentence; Escape to exit.

Book Chat vs Library Chat

Key Features

• Persistent sessions: Chat history is saved per-book. Returning to a book restores your previous conversation.
• Citations: Every AI answer includes inline citations (e.g., Chapter 3, p. 47) that are clickable to jump to the source passage.
• Streaming responses: Answers stream in word-by-word for a natural conversation feel.
• Suggested questions: Chaptera surfaces contextually relevant suggested questions based on your current reading position.
• Context awareness: The AI knows your current reading position and can answer questions specifically about the passage you are reading.
• Conversation management: Start a new conversation, view history, or delete past sessions from the chat panel menu.

Usage Limits

Summaries

Scope Options

Length Options

Pedagogical Approaches

Quiz Generation

Generate multiple-choice quizzes from any scope of book content to test comprehension.

Taking a Quiz

• Questions are presented one at a time. Select an answer and confirm to reveal whether you were correct and why.
• A score summary is shown at the end with per-question breakdown.
• Past quizzes are saved in the Quiz History panel (accessible via the history icon) and can be retaken.

Min tier: Plus

Flashcard Generation

Automatically extract fact-based question/answer pairs from book content and study them with a spaced repetition algorithm.

Min tier: Pro

Study Guide Generation

Study guides are structured, multi-section documents generated from book content — combining summaries, key concepts, timelines, and comprehension questions into a single reference document.

Min tier: Pro

Character Tracker

Automatically extracts and tracks fictional characters from the book, building a structured profile for each one. Best suited for novels and narrative non-fiction. Pro

Scope Options

• Selection — extract characters from selected text
• Chapter — analyse the current chapter
• Page range — specify a start and end page
• Full book — comprehensive extraction across the entire book

Characters can be manually added or edited via the character wizard (click the pencil icon on any character card).

Plot Timeline

Generates a chronological timeline of significant story events, with each event annotated with characters involved and the source chapter. Useful for keeping track of complex narratives with non-linear storytelling. Pro

Concept Extraction

Identifies key concepts, terms, and ideas from the selected scope and presents them as concept cards with AI-generated definitions contextualised to the book. Suited for non-fiction, textbooks, and technical reading. Pro

• Each concept card shows the term, a context-aware definition, and example sentences from the book.
• The concept browser shows all extracted concepts in a searchable, filterable grid.
• Concepts can be added to the Vocabulary Manager with a single click.

Figure Gallery (PDF Books)

For indexed PDF books, the Figure Gallery displays all extracted figures (charts, diagrams, photos, illustrations) as a scrollable thumbnail grid. Plus

Study Guide Viewer

Previously generated study guides (from the AI Generation tab) are accessible here. Each guide is displayed in a structured reader with section-level progress tracking. Mark sections as complete as you study to track your progress through the guide.

Highlights

Select text in the EPUB or PDF reader. A floating toolbar appears — click the highlight colour swatch to apply a colour.

Highlights are rendered directly on the book text and appear in the Annotations sidebar with the surrounding context shown.

Notes

Notes are text annotations attached to a highlight or to a specific position in the book. They can be created from the highlight toolbar (Add Note) or by right-clicking a position and selecting Add Note Here.

• Notes support plain text input.
• Click any note in the Annotations sidebar to jump to its position and open the note editor.
• Notes are editable after creation — click the pencil icon.
• Notes can be added to annotations categories and assigned tags and priority levels.

Bookmarks

All bookmarks support optional notes. Each bookmark tracks how many times you have visited it (visit count), useful for identifying frequently revisited passages.

Annotation Management

Annotations Sidebar (Reader)

Open the Annotations sidebar from the reader toolbar (bookmark icon). It shows all annotations for the current book, filterable by type (Highlights / Notes / Bookmarks) and sortable by position or date created.

Library Annotations View

The main library's Annotations filter tab shows all annotations across your entire library. Filter by book, type, tag, or category.

Advanced Annotation Properties

Export

Export annotations for any book (or all books) from the Annotations sidebar menu or the bulk action toolbar. Supported formats: CSV, Markdown, JSON. The export includes highlight text, note content, position (CFI or page), creation date, colour, tags, and category.

Search

A search bar at the top of the Annotations sidebar searches the highlighted text and note content across all annotations for the current book.

Within-Book Search

Full-text search within the currently open book. Accessible via Ctrl+F or the search icon in the reader toolbar.

Search results are highlighted in the reading area and listed in the search panel. Click any result to jump to it. Use Enter / Shift+Enter to cycle forward/backward through matches.

Library Search

Press Cmd+K (macOS) or Ctrl+K (Windows/Linux) anywhere in the app to open the command palette / library search. Enter a query to search by title and author across all books in your library. Results show cover thumbnail, title, author, and format badge. Press Enter on a result to open the book.

Catalog Search

The Discover page (/catalog) provides search across the public book catalog. Search by title, author, or keyword to find books available for import or purchase. Results can be added to your library directly from the catalog view.

Word Lookup

Double-click any word in the EPUB or PDF reader to trigger an instant lookup. A definition popover appears showing:

• Part of speech (noun, verb, adjective, etc.)
• AI-generated context-aware definition — tailored to how the word is used in this specific book
• Standard dictionary definition
• Pronunciation guide (IPA)
• Pronunciation audio button (plays audio)
• Example sentences from the book
• Save to Vocabulary button

Mastery Levels

Each saved word progresses through five mastery levels based on your flashcard study performance:

Flashcard Study

Study your vocabulary list using spaced repetition. The study mode presents the word on a card; tap or click to reveal the definition. Then rate your recall:

• Easy — extend the review interval significantly
• Good — standard interval increase
• Hard — reduce interval, review sooner
• Again — reset to beginning (word back to Learning)

The SM-2 algorithm schedules the next review time automatically based on your rating history.

Stats Dashboard

The /vocabulary page shows a stats overview:

Word List Management

• Search: Filter your saved words by entering a query in the search box.
• Sort: By date added (newest first / oldest first), alphabetical, or mastery level.
• Edit: Click any word to open an edit dialog where you can customise the definition, add personal notes, or change the mastery level manually.
• Delete: Remove a word from your list via the word card's context menu.
• Export: Download your full vocabulary list as CSV or JSON from the Vocabulary page header menu.

Playback Controls

Word-by-Word Highlighting

As text is read aloud, each word is highlighted in the book text in real time, keeping your visual focus synchronised with the audio. The reader automatically scrolls to keep the current word visible.

Character Quota System

TTS usage is measured in characters of text narrated. Quotas reset monthly.

Overview Dashboard

Reading Heatmap

A GitHub-style contribution heatmap shows reading intensity per day. Toggle between 30-day, 60-day, and 90-day views. Darker cells indicate more reading time on that day.

Multi-Book Charts

A stacked bar chart breaks down reading time per book over the selected time period. A line chart shows daily pages read over time.

Genre Distribution

A pie chart shows reading time broken down by genre (as tagged in book metadata), helping you see how your reading is balanced across subject areas.

Achievements

Achievements are milestone badges awarded automatically when you reach reading milestones.

Earned achievements are displayed on your public profile (if profile visibility is enabled). Locked achievements show a hint of what's required.

Reading Goals

Set monthly or yearly reading goals from the Goals tab of the Analytics page.

Goal progress is shown as a visual progress ring with percentage complete, projected completion date, and a pace indicator (on track / ahead / behind).

Past goals and their outcomes are listed in the Goal History section, including whether the goal was met.

Data Export

Export all your analytics data from the Analytics page header menu. Select a custom date range and download as CSV. The export includes per-session reading records with book, start time, end time, pages read, and device.

Linking Books

Open either the PDF or EPUB version of the book. In the reader toolbar, click Link Format to open the linking dialog. Chaptera will suggest candidate matches from your library based on title and author similarity. Select the matching book and confirm to create the link.

Progress Sync

Once two formats are linked, reading progress is kept in sync. If you read to chapter 5 in the EPUB, opening the PDF will offer to jump to the equivalent position. Position matching uses content-based alignment with a confidence score (0–100%). Matches below 70% confidence are flagged for manual review.

Annotation Sync

Highlights and notes created in one format can be projected to the equivalent location in the other format. The system attempts to locate the same passage in both files and creates a mirrored annotation.

Unlinking

Open the cross-format sync panel and click Unlink Formats. This stops future sync but does not delete any existing annotations on either copy.

Public User Profiles

Each user has a public profile accessible at /u/username. The profile shows:

• Display name and bio
• Reading stats (books read, reading streak) — if visibility is enabled
• Currently reading / recently read books — if activity feed is enabled
• Earned achievements and badges
• Public reading lists and collections
• Public annotations (highlights and notes marked as public)

Profile URL can be customised from User Settings → Account tab.

Friends and Connections

• Search for other users by username or email.
• Send a connection request; the recipient can accept or decline.
• Connected friends appear in your social hub feed.
• View a friend's public profile and reading activity.
• Remove a connection at any time from your connections list.

Shared Reading Lists

Any standard collection can be made public and shared as a reading list. Public reading lists are visible on your profile and can be followed by other users. Followers receive a notification when you add books to the list.

Public Annotations

Individual highlights and notes can be marked as Public from the annotation editor. Public annotations appear on the discoverable annotations feed and can be liked by other users. This makes it easy to discover insightful reader reactions to popular books.

Social Hub

The Social Hub (/social) aggregates activity from your connections — recently read books, new public annotations, and shared reading lists — in a chronological feed. From the feed you can like annotations, follow reading lists, and jump to book pages.

Privacy Controls

All social features are entirely opt-in. A private account shows nothing on a public profile URL.

Team Collaboration Team

Team accounts gain additional collaboration features:

• Shared annotations — highlight and note annotations visible to all team members on shared books
• Group AI Chat — a shared chat session where multiple team members can ask questions and see each other's conversation history
• Team library — a shared book collection accessible to all team members
• Usage dashboard — team admin view of member reading activity and AI usage

Full Feature Comparison

Billing Management

Credit System

Credits allow you to temporarily exceed your tier's usage quotas for AI chat questions, summaries, TTS characters, and PDF conversions. Credits are purchased in bundles from the billing page and are consumed before the monthly quota. Credits do not expire and carry over month to month.

Account Tab

Privacy Tab

Billing Tab