Tool Comparison

Prompt Guardian vs AI Privacy Gateway

Prompt Guardian alternative self-hosted — an in-depth comparison to help you choose the right AI data privacy tool for your stack.

TL;DR: Prompt Guardian — Enterprise prompt security and PII scanning platform. AI Privacy Gateway takes a different approach: a standalone proxy that masks PII at the network layer, requiring zero code changes and keeping data 100% local.

About Prompt Guardian

Prompt Guardian is a commercial enterprise platform for scanning prompts for PII, secrets, and compliance violations before they reach AI providers.

What Prompt Guardian Does Well

Strengths

  • Enterprise compliance reporting
  • SOC 2 certified platform
  • Managed cloud service available

Limitations

  • Closed source, proprietary licensing
  • Cloud-based — data passes through their infrastructure
  • High cost for enterprise tier

Detailed Comparison: Prompt Guardian vs AI Privacy Gateway

Dimension Prompt Guardian AI Privacy Gateway
Data Privacy Data passes through their cloud 100% local — data never leaves your infra
Deployment Cloud or on-prem (enterprise only) Self-hosted in 30 seconds, any environment
Pricing Per-seat enterprise pricing Free Lite, affordable Pro/Enterprise
Open Source Proprietary MIT — full source available
License Proprietary MIT Open Source

Why Teams Choose AI Privacy Gateway Over Prompt Guardian

1

Zero Code Changes

Unlike Prompt Guardian's approach, AI Privacy Gateway works as a network proxy. Deploy the Docker container, change the API base URL — done in 30 seconds.

2

Data Never Leaves Your Infrastructure

All PII masking happens locally. Your data is never sent to a third-party cloud for processing. This is critical for GDPR, HIPAA, and PIPL compliance.

3

MIT Open Source

Full source code available. No vendor lock-in, no per-seat pricing, no usage limits. Deploy anywhere, audit everything.

4

14+ Entity Types

Comprehensive PII detection including phone numbers, emails, ID cards, bank cards, names, addresses, API keys, and Chinese-specific formats.

When Prompt Guardian Might Be the Better Choice

No tool is perfect for every situation. Here is when Prompt Guardian might make more sense:

However, if you need a self-hosted, open-source, zero-code-change solution that works across all your AI APIs, AI Privacy Gateway is the clear choice.

Try AI Privacy Gateway — Free and Open Source

Deploy in 30 seconds. Compare for yourself.

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Frequently Asked Questions

Is AI Privacy Gateway a replacement for Prompt Guardian?

It depends on your use case. AI Privacy Gateway is specifically designed for AI API privacy — masking PII before it reaches any LLM provider. If Prompt Guardian serves a broader or different purpose, they may be complementary rather than direct replacements.

Can I use both Prompt Guardian and AI Privacy Gateway together?

Yes. Many teams use multiple privacy tools for defense-in-depth. AI Privacy Gateway sits at the network layer, so it works alongside any other tool in your stack.

How does the performance compare?

AI Privacy Gateway adds less than 1ms latency per request (Rust-based detection engine). Prompt Guardian's performance characteristics depend on its architecture.