Best LLM Scanners

Interactive tool

Scanner Picker

Describe what you're protecting, your deployment constraints, the threats you care about, and where the scanner has to plug in — get a ranked shortlist of LLM security scanners with a capability matrix, license/cost, and a side-by-side compare of the top three.

Reviewed May 2026. Hard constraints (deployment, budget) knock out tools that can't satisfy them; the rest are scored on how well they fit your target, threat, integration point and language. Every result shows a capability matrix and a transparent pick if / skip if.

What are you protecting?
Deployment constraint
Primary threat focus
Where does it plug in?
Language / SDK
Budget

Full capability matrix

✓ = primary, documented capability · ◐ = partial / possible but not its main job · ✗ = out of scope.

Scanner Host Prompt injectionJailbreakData exfil / leakagePIIToxic contentSupply chain License / cost
garak ↗ Self-host Free / OSS
PyRIT ↗ Self-host Free / OSS
promptmap ↗ Self-host Free / OSS
Rebuff ↗ Self-host Free / OSS (self-host)
LLM Guard ↗ Self-host Free / OSS
Vigil ↗ Self-host Free / OSS
Promptfoo ↗ Self-host Free OSS / paid enterprise
Giskard ↗ Self-host Free OSS / paid hub
DeepTeam (DeepEval) ↗ Self-host Free OSS / paid platform
NeMo Guardrails ↗ Self-host Free / OSS
Guardrails AI ↗ Self-host Free OSS / paid hub
Llama Guard 3 ↗ Self-host Free weights (self-host compute)
Prompt Guard (86M) ↗ Self-host Free weights (self-host compute)
ShieldGemma ↗ Self-host Free weights (self-host compute)
Microsoft Presidio ↗ Self-host Free / OSS
Lakera Guard ↗ API Commercial (API; free tier)
OpenAI Moderation API ↗ API Free (with API account)
Azure AI Content Safety ↗ API Commercial (consumption)
ModelScan ↗ Self-host Free / OSS
picklescan ↗ Self-host Free / OSS
Granica Screen (PII) ↗ API Commercial
Robust Intelligence (Cisco AI Defense) ↗ API Commercial (enterprise)
HiddenLayer AISec Platform ↗ API Commercial (enterprise)
Protect AI Recon ↗ API Commercial

How ranking works & caveats

Capability ratings are our practitioner reading of each tool's documented, in-scope functionality as of the review date — "partial" means it can be made to work but isn't the tool's primary job. Licenses and hosting models change; verify against the upstream project before committing.

Deployment and budget are hard filters — an API-only tool is removed when you require self-host or air-gap, and commercial tools are removed under an OSS-only budget. Remaining tools earn points for matching your threat focus (heaviest weight), protected target, integration point and language/SDK. See the scanner overview and false-positive cost analysis.

Related tools in this network

Other interactive tools across the network that pair well with this one.