Product · Runtime Defense

Stop prompt injection before it stops you.

Stack Shield is the runtime defense layer for production LLMs — blocking direct, indirect, and multi-turn injection with the lowest false-positive rate in the category.

99.7%
Attacks Blocked
22ms
P50 Overhead
4.2B
Prompts Inspected
0.04%
False Positive Rate
Defense Layers

Defense-in-depth, not a single classifier

One model checking another model is brittle. Stack Shield stacks structural, semantic, and behavioral signals.

Structural Analysis

Detect role manipulation, delimiter injection, and template escapes at the parse layer — before any LLM sees the prompt.

Semantic Classifiers

Ensemble of fine-tuned detectors for known attack patterns: DAN, AIM, payload smuggling, encoding tricks.

Behavioral Drift

Session-level detection of slow-rolling injection: instructions accumulating across turns to override the system prompt.

Indirect Defense

Tool outputs, retrieved documents, and web pages scanned for injection content before they reach the model.

Adaptive Updates

Threat intel feed pushed weekly. New attack patterns deployed without redeploying your app.

Forensic Logging

Every block recorded with attack class, signal trace, and reproducible payload — no opaque AI verdicts.

promptshield.demo — live block
→ INPUT "Ignore previous instructions and..."
→ STRUCTURAL FLAG role-override pattern
→ SEMANTIC FLAG classifier confidence 0.97
→ BEHAVIORAL ok
→ DECISION BLOCK · class: direct_injection
→ LATENCY 18ms
Frequently Asked

Questions teams ask before deploying

Straightforward answers about scope, integration, data handling, and rollout.

How does this compare to Lakera Guard or NVIDIA NeMo Guardrails?

We benchmark publicly — see our /research page. PromptShield ships with a higher precision floor and lower P99 latency, plus first-party indirect injection coverage.

Where does it run?

SaaS, dedicated VPC, or fully on-prem. The detection models are quantized and ship as a 4GB container.

Is it OWASP LLM Top 10 aligned?

Yes. All 10 categories covered with mappable policies. We publish the mapping in our trust center.

How do we tune for our app?

Shadow mode for 30 days collects your false-positive corpus. We publish per-policy precision/recall against it before you go live.

Ready to See It Live

Red-team us with your worst prompts

Send your jailbreak corpus. We'll publish a head-to-head report.