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Overview

Screen Answerer requires a Google Gemini API key to process quiz questions and generate answers. Your API key is stored locally in your browser and is never sent to our servers - it goes directly to Google’s Gemini API.
Screen Answerer uses client-side storage for your API key. This means your key stays on your device and is only used to authenticate with Google’s Gemini API.

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Obtaining a Gemini API key

1

Visit Google AI Studio

Navigate to Google AI Studio to access the API key management page.
2

Sign in with your Google account

If you’re not already signed in, use your Google account credentials. You’ll need an active Google account to create API keys.
3

Create a new API key

Click the “Create API Key” button. Google will generate a new key for you instantly.
The Gemini API offers a generous free tier, making it perfect for students and casual users.
4

Copy the API key

Once generated, copy the entire API key. It should follow this format: AIza followed by 35 additional characters (letters, numbers, hyphens, and underscores).
Store your API key securely. Don’t share it publicly or commit it to version control systems.

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Configuring your API key in Screen Answerer

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First-time setup

When you first launch Screen Answerer, you’ll see a welcome message prompting you to configure your API key:
1

Open settings

Click the ⚙️ settings icon in the top-right corner of the application, or click the “Open Settings” button in the welcome message.
2

Navigate to API Key tab

In the settings modal, ensure you’re on the “API Key” tab (it’s the first tab by default).
3

Enter your API key

Paste your Gemini API key into the input field labeled “Enter your Gemini API Key”.
4

Save settings

Click the “Save Settings” button at the bottom of the modal. Screen Answerer will validate your API key by sending a test request to the Gemini API.
If validation succeeds, you’ll see a success message: ”✅ API key validated and saved successfully!”

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API key validation

When you save your API key, Screen Answerer performs validation by:
  1. Format checking - Verifies the key matches the expected pattern: /^AIza[0-9A-Za-z_-]{35}$/
  2. API testing - Sends a test question to the Gemini API to confirm the key works
From server.js:402: 
if (!/^AIza[0-9A-Za-z_-]{35}$/.test(req.body.apiKey)) {
  return res.status(400).json({ 
    error: 'Invalid API key format', 
    message: 'Please provide a valid Gemini API key' 
  });
}

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Updating your API key

To change or update your API key:
  1. Click the ⚙️ settings icon
  2. Navigate to the “API Key” tab
  3. Replace the existing key with your new one
  4. Click “Save Settings” to validate and store the new key

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Security and storage

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Local storage

Your API key is stored in your browser’s localStorage under the key geminiApiKey. This means:
  • Privacy: Your key never passes through Screen Answerer’s servers
  • Persistence: The key remains saved even after closing your browser
  • Direct communication: API requests go straight from your browser to Google
  • The key is stored in plain text in localStorage
  • Anyone with access to your browser can retrieve it
  • Clear your browser data will delete the stored key
  • Use browser profiles or incognito mode for additional isolation

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API key transmission

From index.html:1086-1089, your API key is sent directly to the backend: 
if (apiKey) {
  endpoint = '/process_question_with_key';
  formData.append('apiKey', apiKey);
  formData.append('model', selectedModel);
}
The server validates and uses it to initialize the Gemini client (server.js:426): 
const customGenAI = new GoogleGenerativeAI(req.body.apiKey);

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Troubleshooting

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Invalid API key format

If you see “Invalid API key format”, ensure your key starts with AIza and is exactly 39 characters long.
Double-check that you’ve copied the entire key without any extra spaces or characters.

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Authentication errors

If you receive authentication errors:
  • Verify the API key is active in Google AI Studio
  • Check if the key has been revoked or expired
  • Ensure your Google account has API access enabled

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Quota exceeded

The Gemini API has rate limits. If you exceed your quota, you’ll see: “API quota exceeded. Please try again later.”
From server.js:462-466: 
else if (error.message && error.message.includes('quota')) {
  return res.status(429).json({ 
    error: 'API quota exceeded', 
    message: 'API quota limit reached. Please try again later.' 
  });
}
To resolve quota issues:
  • Wait for the quota to reset (typically every minute)
  • Reduce the frequency of screen monitoring
  • Consider upgrading to a paid tier for higher limits

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Best practices

  • Keep it private: Never share your API key in screenshots, videos, or public repositories
  • Monitor usage: Check your API usage in Google AI Studio regularly
  • Rotate keys: Generate new keys periodically for enhanced security
  • Use separate keys: Consider using different keys for testing and production

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Next steps

Model selection

Choose the right Gemini model for your needs

Settings

Customize your Screen Answerer experience

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