Pitfall 1: Logging sensitive data without disclosure
The mistake: Developers often log function parameters for debugging—`console.log(request.body)` or error handlers—without realizing these logs are captured in Google Cloud Logging and retained for 30 days by default. If the request body contains emails, phone numbers, or other PII, that data is now stored in Google's infrastructure under your project.
Why it happens with Cloud Functions: Unlike client-side tools, Cloud Functions logs are not user-visible and often treated as "internal." Teams assume backend logs are private, not realizing they're subject to the same data protection obligations as user-facing data flows.
Consequence: Undisclosed data processing (GDPR Article 5(1)(a) violation), potential breach notification obligations if logs are compromised, and regulatory fines. DPAs audit log retention practices specifically for this.
Pitfall 2: Missing or incomplete Data Processing Agreement (DPA)
The mistake: Deploying Cloud Functions without executing Google's Data Processing Amendment, relying instead on Google's general privacy policy or assuming the Cloud Terms of Service are sufficient.
Why it happens with Cloud Functions: DPA requirements apply to backend infrastructure just as much as to client SDKs, but teams often conflate "Google Cloud infrastructure" with "Google handles privacy compliance for us." They don't.
Consequence: GDPR Article 28 violation (unlawful processing without a processor agreement); UK ICO and EU DPAs have issued enforcement action against companies using uncontracted third-party processors. Fines up to €10 million or 2% of global turnover.
Pitfall 3: Not updating privacy disclosure after function scope changes
The mistake: Initial privacy policy discloses Cloud Functions processes "user authentication data." Six months later, a new function is added that processes payment details or health information. The privacy policy is never updated.
Why it happens with Cloud Functions: Backend changes feel "internal" and teams often don't notify privacy/legal teams of new functions. There's no client-side SDK update prompt to trigger a policy review.
Consequence: Inaccurate privacy disclosures (GDPR Article 13/14 violation), reduced user consent validity, regulator findings that you processed data outside disclosed scope.
