NeMo Guardrails
NeMo Guardrails is a programmable LLM rails toolkit: you add Colang rails, then read a vulnerability-scan table (continuation, encoding, XSS) that shows how…
OUR TAKE
Pick NeMo Guardrails for app teams who will write Colang and run rails in their own process. $0 is the library, not the model bill.
Good fit
App teams who will write Colang and run rails in their own process.
Poor fit
Teams that want a scan CLI without rails (Garak) or a YAML CI eval (Promptfoo).
NeMo Guardrails
USD, before tax · Checked 2026-10-28 · github.com/NVIDIA-NeMo/Guardrails
OUR TAKE
Pick NeMo Guardrails for app teams who will write Colang and run rails in their own process. $0 is the library, not the model bill.
Good fit
App teams who will write Colang and run rails in their own process.
Poor fit
Teams that want a scan CLI without rails (Garak) or a YAML CI eval (Promptfoo).
NeMo Guardrails
USD, before tax · Checked 2026-10-28 · github.com/NVIDIA-NeMo/Guardrails
What it costs
USD, before tax · Checked 2026-10-28 · github.com/NVIDIA-NeMo/Guardrails
NeMo Guardrails
Apache-2.0. Library + Colang. You pay model inference
$0
No public hosted $.
Not published by the vendor
Not published by the vendor
Checked 2026-10-28·github.com/NVIDIA-NeMo/Guardrails
Before you pay
Good fit
App teams who will write Colang and run rails in their own process.
Poor fit
Teams that want a scan CLI without rails (Garak) or a YAML CI eval (Promptfoo).
Watch out
$0 is the library, not the model bill
Instead, try
Promptfoo if YAML eval + red team when you want Community Free Forever; Phoenix if OTel traces when you need a local observability UI (self-host $0)
Compare NeMo Guardrails with
Limits, in full
- 01
$0 is the library, not the model bill
- 02
You write Colang. This is not a no-code firewall.
- 03
A runtime rail, not an eval warehouse. For traces see Phoenix.
If NeMo Guardrails isn't it
Why: YAML eval + red team when you want Community Free Forever.
Free· open source,MIT
Community red team is 10k probes/monthChecked 2026-10-27·promptfoo.dev/pricing
vs NeMo Guardrails
Why: OTel traces when you need a local observability UI (self-host $0).
Free· paid from$50/mo
ELv2, not ApacheChecked 2026-10-27·arize.com/pricing
vs NeMo GuardrailsLimits & alternatives3 limits · Promptfoo, Phoenix instead
Limits, in full
- 01
$0 is the library, not the model bill
- 02
You write Colang. This is not a no-code firewall.
- 03
A runtime rail, not an eval warehouse. For traces see Phoenix.
If NeMo Guardrails isn't it
Why: YAML eval + red team when you want Community Free Forever.
Free· open source,MIT
Community red team is 10k probes/monthChecked 2026-10-27·promptfoo.dev/pricing
vs NeMo GuardrailsWhy: OTel traces when you need a local observability UI (self-host $0).
Free· paid from$50/mo
ELv2, not ApacheChecked 2026-10-27·arize.com/pricing
vs NeMo Guardrails