Momus — Google Maps Review Analyzer

A Firefox extension that scrapes and analyzes Google Maps reviews for apartment hunting and location research. Momus scrapes every review from a location, flags fake-review patterns and red flags, and, once you've gathered several locations, ranks them side by side with the included scripts/analyze.js script and scripts/compare.html dashboard.

Features

• Complete Review Scraping: Automatically scrolls and loads all reviews from a Google Maps location page
• Fake Review Detection: Calculates a "suspicion score" based on bimodal distribution (lots of 5-star and 1-star, few middle reviews)
• Spelling Error Analysis: Uses Typo.js to count spelling errors in reviews by rating (fake reviews often have more errors in 5-star reviews)
• Red Flag Detection: Automatically flags reviews mentioning pests, mold, crime, management issues, noise, and other problems
• Flexible Export: Download complete data as JSON, or filter to show only 2-4 star reviews (the most informative ones)
• Summary Copy: Quick copy-paste summary of key stats for easy comparison

Installation

Option 1: Load Temporarily (for testing)

1. Download or clone this repository
2. Open Firefox and navigate to about:debugging
3. Click "This Firefox"
4. Click "Load Temporary Add-on..."
5. Navigate to the extension folder and select manifest.json
6. The extension will be loaded until you restart Firefox

Option 2: Create a Distributable Package

Use the included build script. It validates manifest.json, then bundles only the files the extension actually needs (excluding docs, dev scripts, reviews/, node_modules/, and the analysis tooling):

./build.sh
# or, equivalently:
npm run build

If web-ext is installed (npm install -g web-ext), the script uses it and writes the package to artifacts/. Otherwise it falls back to a plain zip, producing momus.zip in the project root.

Then, to install the package in Firefox:

1. Go to about:addons
2. Click the gear icon and select "Install Add-on From File..."
3. Select the built .zip

Note: For permanent installation, the extension needs to be signed by Mozilla.

Usage

1. Navigate to a Google Maps location page (e.g., an apartment complex)
2. Make sure you're on the place page (URL should contain /maps/place/)
3. Click the extension icon in your toolbar
4. Click "Scrape Reviews"
5. Wait for the scraping to complete (may take 30-60 seconds for locations with many reviews)
6. Review the statistics:
   • Total Reviews: Number of reviews scanned
   • Average Rating: Overall star rating
   • 2-4 Star Reviews: Count of "middle" reviews (most informative)
   • Suspicion Score: 0-1 scale, higher = more suspicious distribution (0.8+ is very suspicious)
   • Red Flags: Keywords found and their counts
7. Optional: Check "Only export 2-4 star reviews" to filter your download
8. Click "Download as JSON" to save the full data
9. Click "Copy Summary" to get a quick text summary for pasting

Understanding the Output

Suspicion Score

The suspicion score indicates how "bimodal" the review distribution is:

• 0.0-0.3: Natural distribution with plenty of middle reviews
• 0.4-0.7: Somewhat suspicious, worth investigating
• 0.8-1.0: Highly suspicious - very few middle reviews suggests potential fake review padding

JSON Structure

{
  "name": "Location Name",
  "address": "Full Address",
  "url": "https://www.google.com/maps/place/...",
  "scrapedAt": "2025-01-02T15:30:00.000Z",
  "stats": {
    "averageRating": 4.7,
    "totalReviews": 223,
    "distribution": {"5": 180, "4": 12, "3": 5, "2": 8, "1": 18},
    "googleKeywords": {"maintenance": 76, "team": 28}
  },
  "reviews": [
    {
      "rating": 2,
      "text": "Review text...",
      "date": "2 months ago",
      "author": "John D",
      "isLocalGuide": false,
      "spellingErrors": 3,
      "flaggedKeywords": ["management", "maintenance"]
    }
  ],
  "analysis": {
    "totalScraped": 223,
    "middleReviewCount": 25,
    "suspicionScore": 0.89,
    "spellingErrorsByRating": {"5": 0.3, "4": 1.1, "3": 2.4, "2": 2.9, "1": 3.2},
    "redFlagSummary": {"mold": 3, "roach": 2, "crime": 1},
    "filteredReviews": []
  }
}

Red Flag Keywords

The extension searches for mentions of:

• Pests: roaches, bedbugs, mice, rats, ants, etc.
• Structural Issues: mold, leaks, flooding, water damage
• Safety/Crime: theft, break-ins, drugs, police calls
• Management: ignored requests, unresponsive, deposit issues
• Noise: thin walls, loud neighbors
• Move-out Warnings: "worst apartment", "don't rent", "regret"

Google Keyword Analysis

The extension also analyzes Google's highlighted keywords to see if they're hiding problems:

When Google shows keywords like "maintenance" or "staff" on a location page, the extension checks:

• What percentage of reviews mentioning that keyword are ≤3★?
• What red flags appear alongside that keyword?
• Is the average rating for that keyword lower than the overall rating?

Example warning:

"maintenance" → 65% of reviews are ≤3★
Avg rating: 2.8 | 72% mention red flags: noise(12), broken(8), slow(5)

This helps identify when Google is highlighting keywords that actually correlate with negative experiences.

Comparing Multiple Locations

Once you've scraped several apartments, use the included scripts/analyze.js script to create a ranked spreadsheet:

# Create a folder for your reviews
mkdir reviews
mv ~/Downloads/gmaps_*.json reviews/

# Run the analyzer
node scripts/analyze.js reviews apartment_rankings.csv

This outputs a CSV file with columns:

• Rank: 1, 2, 3, etc.
• Score: Weighted ranking (higher = better)
• Name & Address: Location details
• Critical Flags: Count of deal-breakers (bedbugs, roaches, crime) in middle reviews
• Important Flags: Count of concerns (noise, maintenance, pests) in middle reviews
• Top Middle Flags: Most-mentioned issues in 2-4 star reviews (most trustworthy)
• Top All Flags: Most-mentioned issues across all reviews
• Suspicion Score: Likelihood of fake reviews (lower = better)
• Middle %: Percentage of trustworthy reviews (higher = better)

Customizing Weights

Edit scripts/analyze.js to adjust what matters to you:

// Deal-breakers (high penalty)
const CRITICAL_FLAGS = {
  'bedbugs': 100,
  'roaches': 80,
  'crime': 80,
  // Add your own...
};

// Important concerns (moderate penalty)
const IMPORTANT_FLAGS = {
  'noise': 15,
  'thin walls': 20,
  'maintenance': 10,
  // Add your own...
};

Higher weights = worse penalty. The script focuses on middle review red flags since those are most trustworthy.

Visual Comparison Dashboard

After scraping several apartments, use the comparison dashboard for side-by-side visual analysis:

1. Open scripts/compare.html in your browser
2. Click "Load JSON Files" and select all files from the reviews/ folder
3. Compare apartments side-by-side with these insights:
   • Jaggedness Score: Measures how U-shaped the star distribution is (lower = more natural)
   • Keywords: See which topics have positive vs negative sentiment
   • Distribution Chart: Visual representation of 1★→5★ review counts
   • Critical Flags: Count of deal-breakers (bedbugs, roaches, crime)

Reading the Results:

• Green jaggedness (< 3.0): Smooth curve indicating natural review distribution
• Yellow jaggedness (3.0-6.0): Moderate irregularity, worth investigating
• Red jaggedness (> 6.0): U-shaped distribution suggesting review manipulation
• Keyword colors: Green = mostly positive mentions (≥4★), Red = mostly negative mentions (≤3★)

Sorting: Click any column header to sort by that metric. This helps you quickly find:

• Apartments with the lowest jaggedness (most authentic reviews)
• Best keyword sentiment scores
• Fewest critical flags

The dashboard uses context-aware keyword analysis - "no noise" is correctly identified as positive, not counted as a noise complaint.

Troubleshooting

"Not on a Google Maps place page"

Make sure your URL contains /maps/place/. Navigate to the location first, don't just search for it.

"Could not find review container"

Click on the "Reviews" tab manually first, then run the scraper.

No reviews found

Google may have changed their page structure. Check the browser console for errors and report them as an issue.

Scraping stops early

If the extension doesn't load all reviews, try:

1. Manually scrolling the review panel first
2. Clicking "Reviews" tab to ensure it's active
3. Disabling browser extensions that modify Google Maps

Technical Details

Technologies Used

• Typo.js: Spell checking library using Hunspell dictionaries
• Firefox WebExtensions API: For browser integration
• Content Scripts: Run on Google Maps pages to scrape data

Limitations

• One scrape at a time: The extension scrapes a single location per run; multi-location ranking is done afterward by feeding the saved JSON files to scripts/analyze.js / scripts/compare.html (see "Comparing Multiple Locations" above)
• Client-side only: No server backend, all processing in the browser
• Google Maps only: Doesn't scrape Yelp, ApartmentRatings, etc.
• No date parsing: Dates are stored as-is ("2 months ago") not converted to timestamps
• Page structure dependent: May break if Google updates their HTML structure

Privacy

This extension:

• ✅ Runs entirely locally in your browser
• ✅ Does NOT send any data to external servers
• ✅ Does NOT track you or collect analytics
• ✅ Only activates on Google Maps pages
• ✅ Stores no persistent data (only during active scraping)

Future Enhancements

Ideas for future versions:

• In-extension batch mode (scrape multiple locations in one run, without the manual JSON export/import step)
• Date parsing (convert relative dates to actual dates)
• Cross-platform aggregation (Yelp, etc.)
• Sentiment analysis
• Local storage of past scrapes
• Chrome/Edge support

Development

File Structure

The extension's own source lives at the root (the manifest references it by path); auxiliary tooling and docs live in scripts/ and docs/.

momus/
├── manifest.json           # Extension manifest
├── background.js           # Background script
├── popup/                  # Extension popup UI
│   ├── popup.html
│   ├── popup.js
│   └── popup.css
├── content/                # Scripts that run on Google Maps
│   ├── content.js          # Main orchestrator
│   ├── scraper.js          # DOM parsing logic
│   └── keywords.js         # Red flag keyword list
├── lib/                    # Third-party libraries
│   └── typo.js
├── dictionaries/           # Spell check dictionaries
│   ├── en_US.dic
│   └── en_US.aff
├── icons/                  # Extension icons
├── scripts/                # Auxiliary tooling (not part of the extension)
│   ├── analyze.js          # Rank scraped locations into a CSV
│   ├── reprocess.js        # Re-run analysis on saved JSON
│   ├── compare.html        # Visual comparison dashboard
│   ├── setup-dev.sh        # Python dev-env setup (uv)
│   └── requirements.txt
├── docs/                   # Guides and notes
├── build.sh                # Build the extension package
└── release.sh              # Cut a GitHub release

Making Changes

1. Modify the relevant files
2. Go to about:debugging in Firefox
3. Click "Reload" on the extension
4. Test on a Google Maps location page

Debugging

• Open the browser console (F12) to see [Content] and [Scraper] log messages
• Check the popup console by right-clicking the extension icon → "Inspect"
• Use console.log liberally in development

License

MIT License - feel free to modify and distribute.

Credits

• Typo.js: Christopher Finke (https://github.com/cfinke/Typo.js)
• Hunspell Dictionaries: Various contributors

Support

If you encounter issues:

1. Check the browser console for errors
2. Verify you're on a valid Google Maps place page
3. Try manually clicking the Reviews tab first
4. Report issues with console logs and screenshots

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Disclaimer: This tool is for personal research only. Respect Google's Terms of Service and don't abuse their infrastructure with excessive scraping.