Pick NeMo Guardrails if
app teams who will write Colang and run rails in their own process.
Read the NeMo Guardrails pageNeMo Guardrails vs Promptfoo
Our take
Pick NeMo Guardrails if you're on a app team who will write Colang and run rails in their own process. Pick Promptfoo if you're on a app team who will run Community for $0 (MIT, self-host) and only buy Enterprise when they need SSO, a shared dashboard, and more than 10k probes. Skip NeMo Guardrails if you're on a team that want a scan CLI without rails (Garak) or a YAML CI eval (Promptfoo).
Best for
NeMo Guardrails Runtime guardrails you start at $0
Promptfoo Fail the build before a prompt ships
Free plan
NeMo Guardrails $0 · apache-2.0. Library + Colang. You pay model inference
Promptfoo No free plan
Lowest paid
NeMo Guardrails Not published by the vendor
Promptfoo Not published by the vendor
Coding agent
NeMo Guardrails
Promptfoo Eval matrix
Runs where
NeMo Guardrails Hosted
Promptfoo Hosted
Watch out
NeMo Guardrails $0 is the library, not the model bill
Promptfoo Community red team is 10k probes/month
Last checked
NeMo Guardrails 2026-10-28 · github.com/NVIDIA-NeMo/Guardrails
Promptfoo 2026-10-27 · promptfoo.dev/pricing
Which one, then?
Pick Promptfoo if
app teams who will run Community for $0 (MIT, self-host) and only buy Enterprise when they need SSO, a shared dashboard, and more than 10k probes.
Read the Promptfoo page