LLMFence is the high-performance firewall for autonomous agents. Stop PII leaks, block prompt injection, and enforce brand safety in milliseconds.
Trusted by Industry Leaders
Verify, don't trust
Security tools ask for a lot of trust and publish accuracy numbers nobody can reproduce. These three things are published so you can test them yourself — including the parts that do not flatter us.
18 labelled cases, public domain, run against our real detectors on every build. 3 of them must not be blocked and 5 are context-dependent — because a corpus of attacks alone measures only half the problem.
Test any guardrail with it →A pattern can prove text unsafe. Nothing can prove text safe. Only 10 of those 18 cases are settled without a model — the rest are escalated, because absence of a match is not evidence of safety and we will not pretend otherwise.
How each stage decides →Every response carries X-LLMFence-Source naming which stage answered, so you can measure the real mix on your own traffic rather than taking a number from this page.
Capabilities
One API call. Complete protection for your production AI pipelines.
Define your rules in plain language. They are enforced on every call, alongside the built-in detections -- and the deterministic stages answer in microseconds.
Stages before a model call
Fast-path verdict
rule "Competitor Safety" :
// Prevent leakage
if response.mentions("competitor_x"):
block_with_redaction()
Detects and redacts SSNs, payment card numbers and credentials deterministically, before any model call is made.
Optimized C++ inference core ensures your security layer adds zero perceptible lag to user interactions.
Complete visibility into blocked attempts, risk patterns, and consumption metrics via our immersive console.
Integration
The most powerful security layer is also the simplest to integrate. Language agnostic. REST-native.
Deployed to 200+ edge locations for global coverage.
Native clients for Node.js, Python, and Go.
curl -X POST "https://llmfence.vercel.app/v1/guardrail/check" \
-H "Authorization: Bearer sk_*****" \
-d '{ "text": "..." }'
// Result
{
"status": "secure",
"risk": 0.02
}Latency Performance
Inferences Protected
Uptime Guarantee
Simple Tiers
One powerful engine, three ways to scale. From startup to enterprise.
Scale Confidently
Enterprise Ready