Complement

Help & FAQ

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Getting started, bringing your decks, and making the most of Complement. Find what you need below.

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General Questions

What is Complement?
We built Complement to make studying more effective. It pairs the proven method of spaced repetition with intelligent support from large language models, allowing you to move through material faster, deepen understanding, and retain knowledge more reliably.
Is Complement free?
Yes. Studying, your decks, Anki import, and everything else on the web are free, and the iPhone and iPad app will be too. AI features run on your own OpenRouter account, with your first $1 on us, and an optional subscription pays for semantic search and the other features that run on our servers. See how pricing works.
How is Complement different from other flashcard apps?

Complement integrates AI-powered features to enhance the learning experience:

  • • AI Tutor: Get AI-generated explanations for difficult concepts
  • • Question Generation: Automatically create practice questions
  • • Board-Style Questions: Apply knowledge with exam-style questions
  • • Card Augmentation: Memorize concepts—not cards
  • • Contextual Definitions: Highlight any text for instant context-aware explanations
  • • Studio: Create and manage decks with AI assistance
  • • Advanced Analytics: Track your learning progress with insights

Getting Started

How do I get started?
Getting startedDemo coming soon
Getting startedYour first study session

Step 1: Create an Account

  • • Click "Start free" on the landing page
  • • Sign up by entering your email and password, or sign up with Google
  • • Complete the onboarding process upon login

Step 2: If syncing to/from Anki

  • • From the landing page, navigate to Download
  • • Click "Download for Anki" (compatible with both Mac and Windows)
  • • Restart Anki to have Complement show up in Anki → Tools

Anki Sync

How do I sync my deck TO Complement FROM Anki?
Connector setupDemo coming soon
Connector setupStep-by-step walkthrough

Initial Login:

  • • Navigate to Anki → Tools → Complement → Settings → Login

Syncing to Complement from Anki:

  • • Anki → Tools → Complement → Settings
  • • Choose the deck you would like to sync to Complement
  • • Tools → Complement → Push to Complement
  • • Navigate back to Complement and refresh your page
  • • You should see your deck on the platform to study!
How do I sync a deck FROM Complement TO Anki?
  • • Navigate to Anki → Tools → Complement → Settings
  • • Choose the deck you would like to sync to Anki
  • • Tools → Complement → Pull from Complement
  • • Navigate back to Anki and restart Anki
  • • You should see your deck on Anki to study!

Important Note to Prevent Card Duplication:

If you want to edit a card in Anki from a Complement-created deck:

  1. 1. Select the deck in Anki: Tools → Complement → Settings → Select deck → Save
  2. 2. Go to Tools → Complement → Pull from Complement
  3. 3. Close and reopen Anki, then navigate to Tools → Check Database
  4. 4. Now you're good to go!

FSRS

What is FSRS?
FSRS (Free Spaced Repetition Scheduler) is a modern, open-source spaced repetition algorithm that optimizes your review schedule based on your performance. It's designed to maximize memory retention and minimize review time.
How does FSRS work?

FSRS uses several key principles:

  • • Forgetting Curve: Models how quickly you forget information
  • • Optimal Intervals: Calculates the best time to review each card
  • • Difficulty Adjustment: Adapts to how well you know each card
  • • Stability Tracking: Measures how well information is retained
What are the benefits of FSRS over traditional algorithms?
  • • More Accurate: Better predicts when you'll forget information
  • • Personalized: Adapts to your individual learning patterns
  • • Efficient: Minimizes unnecessary reviews while maintaining retention
  • • Scientific: Based on cognitive science research

Key Features

How do I use Card Augmentation?

Card Augmentation helps you memorize concepts—not specific card phrasings:

  • • Open Study settings (top right corner) and go to AI
  • • Under Rephrasing, set how often review cards are rephrased
  • • AI generates alternative phrasings of card fronts
  • • You can toggle between original and augmented versions while studying
How do Board-Style Questions work?

Board-Style Questions help you practice and apply your learning:

  • • Recommended Settings:
  • - Question Difficulty: Hard
  • - AI Model: Qwen
  • • To integrate into your review flow:
  • - Toggle on "Enable Auto-Board Style Questions"
  • - Questions appear based on your probability settings
  • - Correct answers rate the original card as "Good"
  • - Incorrect answers rate the original card as "Again"
What are Contextual Definitions?

Contextual Definitions provide instant explanations within card context:

  • • Highlight any text in a card to get a definition
  • • Definitions are context-aware based on the card content
  • • Choose your preferred AI model or use default
  • • Toggle "Enable Caching" for faster repeated lookups
  • • A powerful tool to enhance understanding of presented material
What happens when I rate a card as "Again"?

When you rate a card as "Again":

  • • The card will reappear in the same study session after 15 minutes
  • • It enters a relearning phase with shorter intervals
  • • The card's difficulty increases slightly
  • • This helps reinforce challenging material
How do I use the AI Chat feature?
  • • Click the chat icon while studying or browsing cards
  • • Ask questions about the current card or general topics
  • • The AI can explain concepts, provide examples, or clarify confusion
  • • Chat history is saved and can be associated with specific cards

Studio

How do I unsuspend the cards for UWorld questions I have done?

In Studio → Browse, switch the search field to UWorld. The option appears when your deck has AnKing's UWorld tags.

  • • Pick your bank: Step 1, Step 2 or Step 3
  • • Paste the question IDs from your UWorld test, as a list or a column
  • • Every card tagged for those questions appears, in the order you pasted them
  • • Select them and choose Unsuspend. You can undo it from the bar that appears

IDs that matched no card are listed under the field. Cards are found by their AnKing UWorld tags, so this works with AnKing-style decks.

How does Deck Creator work?
Create a deckDemo coming soon
Create a deckStep-by-step walkthrough

Deck Creator generates custom decks from any media you upload:

  • • Select an existing deck to add to, or click "New Deck"
  • • Upload any media files (PDFs, documents, videos, etc.)
  • • Click "Process Files" to extract concepts
  • • Review extracted concepts → "Approve All" or select specific ones
  • • Click "Generate Cards" to create flashcards
  • • Review generated cards, select which to keep
  • • Click "Create X cards" to add them to your deck
  • • AI automatically formats cards with appropriate content and explanations

Analytics

What analytics are available?

Complement provides comprehensive analytics:

  • • Review Timeline: Visual history of your reviews
  • • Due Cards Forecast: See upcoming review schedule
  • • Performance Metrics: Track accuracy by card type
  • • Study Time: Monitor daily study duration
  • • Streak Tracking: Build and maintain study streaks
  • • Difficulty Distribution: Understand your card difficulty spread
  • • Retrievability Analysis: Track memory strength over time
How can I track my board question performance?

Navigate to the Practice page (/practice) to see:

  • • Total questions attempted and accuracy
  • • Current and longest streaks
  • • Performance by difficulty level
  • • Time spent per question
  • • Detailed history with explanations
What do the different card states mean?
  • New: Cards you haven't studied yet
  • Learning: Cards in early learning stages
  • Review: Cards in long-term review cycle
  • Relearning: Cards you've forgotten and are relearning

Technical

What browsers are supported?

Complement works best on modern browsers:

  • • Chrome (recommended)
  • • Firefox
  • • Safari
  • • Edge
Can I use Complement offline?

Currently, Complement requires an internet connection for:

  • • Syncing data with our servers
  • • AI features (chat, explanations, question generation)
  • • Analytics and progress tracking

Offline mode is on our roadmap for future development.

Is my data secure?

Yes, Complement uses industry-standard security:

  • • Supabase for secure authentication and data storage
  • • Row-level security to protect your data
  • • Encrypted connections for all data transfers
  • • No local storage of sensitive information
  • • Regular security audits and updates

Troubleshooting

Cards aren't appearing in my study session

Check the following:

  • • Ensure cards are due for review (check Analytics)
  • • Verify the correct deck is selected
  • • Check if cards are suspended (yellow highlight in browser)
  • • Confirm your study settings allow for the card types you expect
Sync with Anki isn't working

Ensure:

  • • Complement Connector add-on is installed in Anki
  • • Anki is running during sync
  • • You're logged in through Tools → Complement → Settings → Login
  • • The correct deck is selected in settings
  • • You've restarted Anki after installation

If you are still having issues, please contact us via the feedback form.

FSRS parameters showing "NaNy"

If you see "NaNy" for your FSRS card parameters, follow these steps:

  1. 1. Navigate to Settings in your Complement Dashboard
  2. 2. Scroll down to "Advanced Scheduling"
  3. 3. Scroll down to "FSRS Data Maintenance"
  4. 4. Click "Fix Missing Card States"
How do I prevent card duplication when syncing?

To prevent duplicate cards when editing Complement-created decks in Anki:

  1. 1. After pulling a deck from Complement to Anki
  2. 2. Close and reopen Anki
  3. 3. Navigate to Tools → Check Database
  4. 4. This ensures Anki properly tracks the card IDs

This step is only needed once per deck after initial sync.

Still have questions?

Contact us through the feedback form in your dashboard. For bug reports, include the steps to reproduce the issue and any relevant screenshots.

FAQ · Complement