Adversary Emulation Library vs Caldera: 2026 Comparison
Adversary Emulation Library is a free threat simulation tool. Caldera is a free threat simulation tool. Compare features, ratings, integrations, and community reviews side by side to find the best threat simulation fit for your security stack.
CST VerdictBased on our analysis of available product data, here is our conclusion:
Security teams building a testing program from scratch should start with Adversary Emulation Library because it's free, well-maintained, and maps directly to real adversary TTPs instead of generic control checklists. The library has 2,076 GitHub stars and covers MITRE ATT&CK techniques across multiple threat groups, giving you actual playbooks to run rather than vague scenarios. Skip this if your team lacks the time or expertise to operationalize emulation plans internally; you'll need engineers who can translate documentation into executable tests, not a turnkey platform that runs attacks for you.
Security teams building an adversary emulation program on a shoestring budget should start with Caldera; it's the only free framework that lets you automate attack chains against your own infrastructure without vendor lock-in. MITRE's backing means the technique mappings to ATT&CK are authoritative, and you get a real agent-based architecture that scales across hundreds of endpoints. Skip this if you need a polished UI or managed red team operators; Caldera requires security staff who are comfortable with YAML configurations and Python customization to extract value.
