Now with x402 crypto payments

The Security Layer
for AI Infrastructure

Protect your AI agents from prompt injection attacks and credential leaks. Stronghold scans every request through a transparent proxy, blocking threats before they reach your models.

View on GitHub
User
Stronghold
AI
ALLOW
WARN
BLOCK
The Risk

AI Agents Are Vulnerable

As AI agents gain access to sensitive data and systems, they become prime targets. Traditional security tools weren't built for this threat model.

Without Stronghold

  • ×Direct access to AI models
  • ×No input validation
  • ×Sensitive data exposed in outputs
  • ×No audit trail of requests
  • ×Attacks go undetected

With Stronghold

  • Transparent proxy intercepts all traffic
  • 4-layer scanning detects attacks
  • Credential leaks blocked automatically
  • Complete audit trail via headers
  • Real-time threat detection

Prompt Injection

Attackers embed malicious instructions that override your system prompts.

Credential Leaks

AI models accidentally expose API keys, passwords, or sensitive data.

Jailbreak Attacks

Sophisticated techniques bypass safety guardrails entirely.

Data Exfiltration

Malicious prompts trick AI into sending private data to attackers.

How It Works

Transparent Protection

Install once. Protect everything. Stronghold operates at the network level, so it works with any AI agent without code changes.

01

Install

One command setup with automatic OS keyring configuration. Your wallet is created locally—private keys never leave your device.

$ curl -fsSL https://install.stronghold.security | sh
02

Enable

Transparent proxy intercepts all HTTP/HTTPS traffic at the network level. Works system-wide, no code changes needed.

$ sudo stronghold enable
03

Scan

Every request is analyzed for prompt injection, credential leaks, and jailbreak attempts. Threats blocked in under 50ms.

$ stronghold status
Uses iptables/nftables on Linux, pf on macOS — cannot be bypassed
Features

Everything You Need to Secure AI

A complete security layer designed specifically for AI infrastructure. Self-hosted, open source, and crypto-native.

4-Layer Defense

Prompt Injection Detection

4-layer scanning architecture: heuristics, ML classification, semantic similarity, and LLM classification catch even sophisticated attacks.

Output Protection

Credential Leak Prevention

Scans LLM outputs for API keys, passwords, and sensitive data patterns. Blocks accidental exfiltration before it reaches users.

Zero Config

Transparent Proxy

System-wide protection at the network level. No code changes, no environment variables, no proxy configuration needed.

$0.001/scan

x402 Payments

Pay-per-scan using USDC on Base. No subscriptions, no upfront costs. Only pay for what you use with crypto-native payments.

Non-Custodial

Local Wallet

Private keys stored in your OS keyring (macOS Keychain, Linux Secret Service, Windows Credential). Keys never leave your device.

<50ms Latency

Real-time Blocking

Sub-50ms latency with instant ALLOW/WARN/BLOCK decisions. Malicious requests stopped before they reach your AI models.

CLI Experience

Simple, Powerful, Fast

stronghold — zsh
$
Pricing

Simple, Transparent Pricing

Pay only for what you use. No subscriptions, no hidden fees. Powered by the x402 payment protocol.

Self-Hosted

Run your own instance

FreeOpen source
  • Full source code access
  • Self-hosted proxy
  • Bring your own API keys
  • Community support
  • Manual x402 payments
Most Popular

Pay Per Scan

Usage-based pricing

$0.001–0.005per scan
  • Managed infrastructure
  • Automatic scaling
  • Usage dashboard
  • Email support
  • x402 crypto payments
  • Sub-50ms latency SLA

Enterprise

For large organizations

CustomContact us
  • Dedicated infrastructure
  • Custom ML models
  • SSO & audit logs
  • 24/7 phone support
  • Custom integrations
  • SLA guarantees
Payments powered by x402 — the open standard for internet payments

Built for AI Engineers, by AI Engineers

Open Source
MIT Licensed
Self-Hostable
Run on your infrastructure
Non-Custodial
You control your keys
Community Driven
Built by AI engineers
<50ms
Scan Latency
4-Layer
Defense Stack
100%
Open Source
FAQ

Common Questions

Stronghold is a security layer for AI infrastructure that protects agents from prompt injection attacks and credential leaks. It operates as a transparent proxy, scanning all HTTP/HTTPS traffic before it reaches your AI models.