Anonymizer User Guide

Complete guide to protecting sensitive information with privacy-first PII detection and anonymization

Quick Navigation

→ Getting Started → Detection Methods → Basic Workflow → File Upload → Entity Management → LLM Integration → Redact Mode → Export & Import → Privacy & Security → Best Practices

1. Getting Started

The Anonymizer is a privacy-first tool that detects and anonymizes Personally Identifiable Information (PII) entirely within your browser. No data ever leaves your device, ensuring complete privacy.

🔒 Privacy Guarantee: All processing happens locally in your browser. Your text is never transmitted to any server.

What is detected? The Anonymizer recognizes 75+ types of PII including:

  • Personal information: Names, emails, phone numbers, addresses
  • Financial data: Credit cards, IBANs, cryptocurrency addresses
  • Identification: SSNs, passports, driver licenses, tax IDs
  • Country-specific: Swiss AHV, German tax ID, UK NINO, and more
  • Technical: IP addresses, URLs, MAC addresses, UUIDs

2. Detection Methods

The Anonymizer offers three detection methods. Choose based on your needs for speed, accuracy, and language support:

⚡

Regex - Pattern Matching

Fast pattern-based detection

  • ✓ Instant results
  • ✓ Works completely offline
  • ✓ No model download required
  • ✓ Good for structured data (emails, phones, SSNs)

Best for: Quick checks, structured formats

🤖

AI4Privacy - English

AI-powered token classification

  • ✓ Context-aware detection
  • ✓ Understands natural language
  • ✓ Catches names in context
  • ⚠ First load downloads model (~50MB)

Best for: English documents, complex text

🌍

AI4Privacy - Multilingual

AI detection for multiple languages

  • ✓ Supports many languages
  • ✓ Context-aware detection
  • ✓ Best for non-English text
  • ⚠ Larger model, slower first load

Best for: Non-English or mixed-language content

💡 How AI Detection Works: The AI4Privacy models use token classification with BIO tagging. The model analyzes each word in context and assigns a probability score for being sensitive information. This means it can detect names like "John" even without a surname, based on surrounding context.

3. Basic Anonymization Workflow

1

Enter or Paste Text

Type or paste your text into the Input Text area. You can also drag-and-drop files.

Example: "My name is John Smith, email john@example.com, phone (555) 123-4567"
2

Select Detection Method

Choose from the dropdown: Regex - Pattern Matching for instant results, or AI4Privacy - English/Multilingual for context-aware AI detection.

3

Click Anonymize

Press the 🛡️ Anonymize button. The tool will detect all PII and replace it with placeholders.

Result: "My name is [PERSON_NAME_1], email [EMAIL_1], phone [PHONE_1]"
4

Review & Copy

Check the Detected Entities panel, review the anonymized output, and click 📋 Copy to use elsewhere.

4. File Upload & Processing

The Anonymizer supports multiple file formats for easy text extraction:

📄

.txt Files

Plain text documents

📝

.docx Files

Microsoft Word documents

📕

.pdf Files

PDF documents (text-based)

Two Ways to Upload:

  • Click Method: Click 📁 Load File button and select your file
  • Drag & Drop: Drag file directly onto the Input Text area

⚠ Limits: Maximum file size is 10MB. Scanned PDFs (images) are not supported.

5. Entity Management

The Detected Entities panel shows all found PII with their placeholders and original values:

👁️ View Options

  • • Tiles View: Compact grid layout
  • • List View: Detailed list format

🔀 Sorting Options

  • • By Appearance: Order as they appear
  • • Alphabetical: Sort by entity type

🗑️ Managing Entities

  • Remove Entity: Click the trash icon (🗑️) on any entity to remove it and restore the original value in the output
  • Entity Stats: View total and active entity counts at the bottom of the panel
  • Manual Selection: Use "Anonymize Selected Text" to manually anonymize specific portions

6. LLM Integration & Deanonymization

Use the Anonymizer to safely process text with AI services like ChatGPT, Claude, or others:

1

Anonymize Your Text

Use the main anonymization feature to protect your PII. Copy the anonymized output.

2

Send to LLM

Paste the anonymized text into ChatGPT, Claude, or any AI service. The placeholders like [PERSON_NAME_1] will be preserved.

3

Get AI Response

The AI will process your text and maintain the placeholders in its response.

4

Deanonymize

Paste the AI response into the LLM Input field and click 🔓 Deanonymize. All placeholders will be replaced with original values!

💡 Pro Tip: Export your entities as CSV before closing the page. This lets you deanonymize responses even days later!

7. Redact Mode

For maximum privacy when sharing with untrusted parties, use Redact Mode:

🛡️ Anonymize Mode

Default mode with unique placeholders:

[PERSON_NAME_1], [EMAIL_1], [PHONE_1]

🔒 Redact Mode

All entities replaced with [redacted]:

[redacted], [redacted], [redacted]

When to use Redact Mode:

  • Sharing documents with untrusted parties
  • Public posting or publishing
  • When you don't need to reverse the anonymization
  • Maximum privacy protection

✓ Good to know: Even in Redact Mode, you can still deanonymize using the entity list, as the mapping is preserved internally!

8. Export & Import Entities

Preserve your entity mappings for later use or share them with trusted recipients:

💾 Export Entities

  1. 1. After anonymization, click 💾 Export CSV
  2. 2. Save the file with a descriptive name
  3. 3. Store securely (file contains PII!)
CSV Format:
"Placeholder","Original","Type","Active"
"[EMAIL_1]","john@example.com","EMAIL","true"

📥 Import Entities

  1. 1. Click 📥 Import button
  2. 2. Select your previously exported CSV file
  3. 3. Entity list will populate automatically
  4. 4. Now you can deanonymize LLM outputs!

⚠ Security Warning: CSV files contain the original ↔ placeholder mapping. Protect these files like you would the original sensitive data. Use encryption when storing or sharing.

9. Privacy & Security

🔒 Privacy Guarantees

  • ✓ 100% Client-Side: All processing happens in your browser. Zero server communication.
  • ✓ No Data Transmission: Your text never leaves your device.
  • ✓ Memory-Only Storage: Entity mappings stored in RAM only, cleared when you close the page.
  • ✓ No Cookies or Tracking: No localStorage, no cookies, no analytics for PII data.

Best Security Practices:

  • Use on trusted devices only (not public computers)
  • Clear browser cache after processing highly sensitive data
  • Encrypt CSV exports before storing
  • Always review anonymized output before sharing
  • Use Redact Mode for untrusted recipients

10. Best Practices & Tips

💡 For Maximum Privacy

  • • Use Redact Mode for public sharing
  • • Clear all data after each session
  • • Don't share entity CSV files publicly
  • • Process offline when possible

🎯 For Best Accuracy

  • • Use AI4Privacy modes for complex text
  • • Review detected entities manually
  • • Format text properly (standard dates/phones)
  • • Remove false positives from entity list

⚡ For Performance

  • • Use Regex mode for instant results
  • • Process large docs in batches
  • • Close unused browser tabs
  • • Desktop browsers work best

🔄 For LLM Workflows

  • • Export entities before using LLM
  • • Keep CSV files organized
  • • Test deanonymization first
  • • Document your workflow

📚 Additional Resources

Need Help?

Supported Entity Types

75+ types including names, emails, phones, credit cards, SSNs, passports, IBANs, IP addresses, URLs, Swiss AHV, German tax IDs, UK NINO, and more.

Try the Anonymizer Now →