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.
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
- ×Prompts hijacked by injection attacks
- ×API keys and secrets leak through model outputs
- ×No visibility into agent network traffic
- ×Threats bypass your application layer undetected
With Stronghold
- ✓Every request scanned before reaching your models
- ✓4-layer defense blocks injection attacks
- ✓Credentials and secrets caught in real time
- ✓Full visibility into all agent traffic
Prompt Injection Defense
Malicious instructions embedded in user inputs get caught by 4-layer scanning before they can hijack your agent’s behavior.
Credential Leak Prevention
API keys, passwords, and secrets in LLM outputs are detected and blocked before they ever leave your system.
Plug & Play for Any Agent
Drop Stronghold into your existing agent setup with zero code changes. Network-level interception works with any framework or model provider.
Autonomous Agent Payments
Your agent pays per scan automatically via its local wallet. No subscriptions, no API keys to manage, no human in the loop for billing.
Transparent Protection
Install once. Protect everything. Stronghold operates at the network level, so it works with any AI agent without code changes.
Install
One command setup with automatic OS keyring configuration. Your wallet is created locally—private keys never leave your device.
Enable
Transparent proxy intercepts all HTTP/HTTPS traffic at the network level. Works system-wide, no code changes needed.
Verify
Confirm your setup is running properly. Once enabled, Stronghold automatically scans every request and response—you’re protected.
Everything You Need to Secure AI
A complete security layer designed specifically for AI infrastructure. Self-hosted, open source, and pay-as-you-go.
Prompt Injection Detection
4-layer scanning architecture: heuristics, ML classification, semantic similarity, and LLM classification catch even sophisticated attacks.
Credential Leak Prevention
Scans LLM outputs for API keys, passwords, and sensitive data patterns. Blocks accidental exfiltration before it reaches users.
Transparent Proxy
System-wide protection at the network level. No code changes, no environment variables, no proxy configuration needed.
Pay As You Go
Pay-per-scan with no subscriptions or upfront costs. Only pay for what you use. Top up via dashboard with card or crypto.
Real-time Blocking
Sub-50ms latency with instant ALLOW/WARN/BLOCK decisions. Malicious requests stopped before they reach your AI models.
Simple, Powerful, Fast
Simple, Transparent Pricing
Same price, two payment paths. Choose crypto for autonomous agents or card billing for business integration.
$0.001 per request — both payment methods, same rate
Individual
For developers running autonomous AI agents
- x402 crypto payments (USDC)
- Autonomous agent billing
- No human in the loop
- CLI + transparent proxy
Agents pay per-request with USDC wallets — no human intervention needed for billing.
Get StartedBusiness
For companies integrating scanning into their stack
- Card billing via Stripe
- Prepaid credits + metered overflow
- API keys for server-to-server
- SSO login (WorkOS)
Use API keys with standard card billing — no crypto wallet or blockchain knowledge required.
Sign In with SSOBuilt for AI Engineers, by AI Engineers
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 — or as a direct API for server-side integration.