Developer builds PII firewall to block sensitive data from LLM prompts

By PulseAugur Editorial · [1 sources] · 2026-06-19 02:03

A developer built a PII firewall for LLM interactions to prevent sensitive data from being sent to cloud-based models. The system, implemented using FastAPI and Microsoft Presidio, scans prompts before they reach models like GPT-4o, blocking any that contain personally identifiable information or violate defined policies. This approach ensures compliance with regulations like GDPR by preventing data exfiltration rather than just logging it. AI

IMPACT Enables developers to build more compliant LLM applications by preventing accidental PII leakage to third-party models.

RANK_REASON The item describes a specific tool/framework built by a developer to address a problem, rather than a new model release or significant industry-wide event.

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AI-generated summary · Google Gemini · from 1 sources. How we write summaries →

Developer builds PII firewall to block sensitive data from LLM prompts

COVERAGE [1]

dev.to — LLM tag TIER_1 English(EN) · Sourish Chakraborty · 2026-06-19 02:03

I Built a PII Firewall for LLMs in a Weekend (and Caught My Own Leak)

<p>Three weeks ago I was benchmarking GPT-4o against a local Llama model. I was copying prompts from a real support ticket database to make the test realistic. Midway through the run I glanced at the terminal and saw this in the logs:<br /> </p> <div class="highlight js-code-high…

COVERAGE [1]

I Built a PII Firewall for LLMs in a Weekend (and Caught My Own Leak)

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