The cloud firewall problem
Here's how most AI firewalls work today: your application sends a request to the LLM. But instead of going directly to the model, it first routes through a cloud API operated by the firewall vendor. They scan it for prompt injections, PII, and other threats. Then they forward it to your model. The response comes back the same way.
This architecture has three fundamental problems.
1. Latency
Cloud-based firewalls add a full network round-trip to every AI request. Even with low-latency cloud infrastructure, you're looking at 100–200ms of additional overhead per request. For real-time AI applications — chatbots, agents executing trades, co-pilots generating code — that latency compounds fast.
Aegis adds 2ms. Because the classifier runs in-process, there's no network hop. The local LLM classifier evaluates the request via direct FFI in the same process as your proxy, then passes it through.
2. Data privacy
When you route AI traffic through a cloud firewall, your prompts, user data, and API responses all transit through infrastructure you don't control. For companies handling financial data, health records, or wallet signing operations, this is a compliance and security liability.
With Aegis, your data never leaves your machine. The classifier, pattern matching, and PII detection all run locally. After install, the binary works completely offline.
3. Attack surface
A cloud firewall is a single point of failure and a high-value target. If the vendor's infrastructure is compromised, every customer's AI traffic is exposed. You're trusting a third party with the most sensitive layer of your AI stack.
Aegis eliminates this surface entirely. No external API to compromise. No shared infrastructure. Your firewall runs in your environment, under your control.
The Rust advantage
We built Aegis in Rust because this is infrastructure that sits in the hot path of every AI request. Rust gives us:
- No garbage collection pauses — predictable latency at the p99
- Memory safety without runtime overhead — no segfaults, no buffer overflows
- Single static binary — no dependencies, no containers, no runtime to manage
- Efficient FFI — the local LLM classifier integrates directly without serialization overhead
The result is a firewall that's both faster and more secure than its cloud-based alternatives.
The bottom line
AI security shouldn't require routing your data through another cloud provider. It shouldn't add hundreds of milliseconds to every request. And it shouldn't cost thousands of dollars per year for basic protection.
Aegis is local, fast, and free. Install Shield in 60 seconds →