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Apps Handling Sensitive Personal Data

Some types of personal data are considered sensitive under privacy laws. If your app collects, stores, or processes this data, you have additional legal and security obligations.

This page explains what counts as sensitive data, what risks come with it, and what you need to do to handle it responsibly.

What Is Sensitive Personal Data?​

Different laws define sensitive data slightly differently, but they generally include:

CategoryExamples
Health dataMedical records, insurance info, fitness/health tracking data
Biometric dataFingerprints, facial recognition data, voice prints
Genetic dataDNA, genetic test results
Financial dataBank accounts, credit card numbers, income information
Government IDsPassport numbers, driver's license, social security numbers
Political opinionsParty affiliation, voting history, political donations
Religious beliefsReligious affiliation, beliefs, practices
Sexual orientationSexual orientation, gender identity
Criminal recordsCriminal history, arrests, convictions
Children's dataAny data from users under 13 (US) or 16 (EU)
Location dataPrecise GPS location, movement patterns

Why Sensitive Data Requires Extra Care​

Sensitive data is protected by additional regulations:

RegulationAdditional Requirements
GDPR (EU)Explicit consent required, Data Protection Impact Assessment (DPIA) needed
CCPA (California)Right to limit use of sensitive data
HIPAA (US)Strict rules for health data
COPPA (US)Special rules for children's data
PIPEDA (Canada)Consent required for sensitive data

Fines for mishandling sensitive data are significantly higher than for regular data.

Higher Security Risk​

Sensitive data is more valuable to attackers:

  • Health records sell for $50-200 each on the black market (vs. $1-5 for credit card numbers)
  • Government IDs enable identity theft and fraud
  • Biometric data cannot be changed — once your fingerprint is stolen, it's stolen forever

Higher Reputational Risk​

A breach of sensitive data causes more damage:

  • Users lose trust more quickly
  • Media coverage is more intense
  • Regulatory scrutiny is more severe
  • Business recovery is harder

Common Mistakes With Sensitive Data​

Mistake 1: Collecting Data You Don't Need​

"I'll collect it just in case."

The safest approach is to not collect sensitive data at all unless you absolutely need it.

Ask yourself:

  • Do I really need their date of birth, or just "over 18"?
  • Do I need their exact location, or just their city?
  • Do I need their full government ID, or just verification that it's valid?

Best practice: Collect the minimum data required to provide your service.

Mistake 2: Storing Sensitive Data Without Encryption​

If you must store sensitive data, it must be encrypted:

  • At rest: Encrypted in the database
  • In transit: Encrypted via HTTPS
  • In use: Minimize access to decrypted data

Ask your developer or AI:

"Is sensitive data encrypted in the database? What encryption algorithm is used? How are encryption keys managed?"

Mistake 3: Not Controlling Access​

Sensitive data should only be accessible to people who absolutely need it:

  • Not all team members need access to user data
  • Not all app features need access to sensitive fields
  • Access should be logged and audited

Mistake 4: Keeping Data Forever​

Sensitive data should have a retention policy:

  • How long do you keep it?
  • When do you delete it?
  • How do you delete it securely?

Best practice: Delete sensitive data as soon as you no longer need it for the purpose it was collected.

How to Handle Sensitive Data Safely​

1. Minimize Collection​

Before adding a field that collects sensitive data, ask:

  • Is this absolutely necessary for my app to function?
  • Can I use a less sensitive alternative?
  • Can I use a third-party service that handles the sensitive part?

2. Encrypt Everything​

// Storing sensitive data in plain text
db.users.insert({
  ssn: "123-45-6789",
  income: 75000
});

// Encrypt sensitive fields
const encryptedSSN = encrypt(ssn, ENCRYPTION_KEY);
db.users.insert({
  ssn: encryptedSSN,
  income: 75000  // Consider if this needs encryption too
});

3. Implement Strict Access Controls​

  • Role-based access (admin, staff, user)
  • Field-level access (some users see name, only admin sees SSN)
  • Audit logging (every access to sensitive data is logged)
  • Automatic timeout (sessions expire after inactivity)

4. Use Purpose Limitation​

Only use sensitive data for the purpose it was collected:

  • If you collect health data for account setup, don't use it for marketing
  • If you collect location data for delivery, don't use it for analytics
  • Document your data purposes in your privacy policy

5. Have a Data Deletion Process​

Users have the right to request deletion of their data. For sensitive data, this is especially important:

  • Provide a way for users to request deletion
  • Verify the user's identity before deleting
  • Delete data from all systems (database, backups, logs)
  • Confirm deletion to the user

When to Use Third-Party Services​

For many types of sensitive data, the safest approach is to not handle it yourself:

Sensitive DataUse Instead
Credit cardsStripe, PayPal, Square (they handle PCI compliance)
Government ID verificationStripe Identity, Onfido, Jumio
Health recordsHIPAA-compliant platforms (if you must)
AuthenticationAuth0, Clerk, Supabase Auth
PaymentsStripe, Paddle, Lemon Squeezy

These services handle the security, compliance, and liability so you don't have to.

The Sensitive Data Checklist​

  • Do I actually need this sensitive data? Can I use a less sensitive alternative?
  • Is sensitive data encrypted at rest in the database?
  • Is HTTPS enforced for all data transmission?
  • Are access controls in place (who can view/modify sensitive data)?
  • Is access to sensitive data logged?
  • Is there a data retention policy (how long to keep, when to delete)?
  • Can users request deletion of their data?
  • Is there a process for secure data deletion?
  • Are third-party services used where possible instead of handling sensitive data directly?
  • Is the privacy policy updated to reflect sensitive data collection?
  • Is explicit consent obtained for sensitive data collection?
  • Is a Data Protection Impact Assessment (DPIA) needed?

The Bottom Line​

If you don't need sensitive data, don't collect it. If you must collect it, treat it with the highest level of security and care.

Sensitive data is not like other data. It comes with higher legal risk, higher security requirements, and higher user expectations. Before adding a field that collects sensitive information, ask yourself if it's truly necessary — and if it is, make sure you have the security measures in place to protect it.

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