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Alternatives

Products that do what PromptGuard does

The firewall for AI prompts. Drop-in security for LLM apps.

  1. 1

    Prompt-injection firewall for prod LLM apps

    Jul 2026 · insightits.com

  2. 2OS

    Hi HN, Matvey, Ildar, Joey, and Dominik here. If you're building LLM agents that use tools, you're probably worried about prompt injection attacks that can hijack those tools. We were too, and found that solutions like prompt-based filtering or secondary "guard" LLMs can be unreliable. Our thesis is that agent security should be handled at the network level between the agent and the LLM, just like a traditional web application firewall. So we built Archestra Platform: an open-source gateway that acts as a secure proxy for your AI agents. It's designed to be a deterministic firewall against…

    Oct 2025 · archestra.ai

  3. 3

    The AI firewall that understands compliance context

    Dec 2025 · promptlock.io

  4. 4
    HOL Guard106

    The 1st Firewall for AI Agents

    Jul 2026 · hol.org

  5. 5

    Protect your LLM applications with a few lines of code.

    2023

  6. 6
    CtrlAI104

    Transparent proxy that secures AI agents with guardrails

    Mar 2026 · github.com

  7. 7

    Prompt security analysis

    Nov 2025

  8. 8

    Stop prompt injection before it reaches your AI agent

    26d ago · mcp.glc-rag.hu

  9. 9

    Block malicious web content before it reaches your AI.

    Jan 2026

  10. 10

    Stop malicious AI prompts in 1 API call

    2025

  11. 11

    Stop prompt injection from triggering tools.

    Feb 2026 · github.com

  12. 12

    Tiny prompt-injection firewall for LLM chat apps. 14 MB.

    May 2026 · github.com

  13. 13
    GitHub2

    Local sensitive data & API key blocker for ChatGPT.

    Jun 2026 · github.com

  14. 14

    Monitor and protect your org data

    Apr 2026 · aifitechnology.com

  15. 15

    "Your LLM's last line of defence against the internet."

    May 2026 · wonderwallai.skintlabs.ai

  16. 16

    Unit-Test Security for LLM Apps

    2025

  17. 17

    The firewall for AI agents. Block dangerous commands

    Dec 2025 · mcp-shield.vercel.app

  18. 18LC
  19. 19

    Just stop jailbreaks & prompt hacks with one API call.

    Sep 2025

  20. 20IM
  21. 21IB

    Hi HN, I’m the creator of Cordum. I’ve been working in DevOps and infrastructure for years (currently in the fintech/security space), and as I started playing with AI agents, I noticed a scary pattern. Most "safety" mechanisms rely on system prompts ("Please don't do X") or flimsy Python logic inside the agent itself. If we treat agents as autonomous employees, giving them root access and hoping they listen to instructions felt insane to me. I wanted a way to enforce hard constraints that the LLM cannot override, no matter how "jailbroken" it gets. So I built Cordum. It’s an open-source…

    Jan 2026 · github.com

  22. 22

    Stop malicious prompts before they reach your AI

    Dec 2025 · antijection.com

  23. 23

    Self-hosted LLM guard — auditable blocks, not scores

    Jul 2026 · insightits.com

  24. 24PI

    People seem to be blindly hooking up their OpenClaw’s to their personal data. So, I built runtime controls to prevent at the least, very simple prompt injection attacks. Once installed, it hooks to Node.js child_process module in the gateway process and listens to tool calls and their response streams. And a fetch hook to monitor user prompts (both could’ve been through fetch, happy to discuss why this whole layer couldn’t just be a proxy). There are two layers of protection: First: Whenever there is a read-only tool call whose response an attacker can modify, we extract that part of the…

    Feb 2026 · github.com

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