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Head to head · Guard moderation · October 2026 research run

Mistral Moderation API vs NVIDIA NeMo Guardrails

NVIDIA NeMo Guardrails has a score of 68.7 (B) against Mistral Moderation API's 58.6 (C). Both do guard moderation. The largest gap is maintenance & community, 47 points.

Mistral Moderation APIMistral AI · HTTP API C58.6/100#278 of 452 NVIDIA NeMo GuardrailsNVIDIA · Agent framework B68.7/100#120 of 452

Which one, for what

Pick Mistral Moderation API for

  • schema & documentation (+16)
  • agent ergonomics (+8)
  • transparency & trust (+12)

Pick NVIDIA NeMo Guardrails for

  • reliability (+35)
  • security & auth (+8)
  • payments & pricing (+20)
  • maintenance & community (+47)

Score by category

CategoryWeight this runMistral Moderation APINVIDIA NeMo GuardrailsEdge
Reliability16%204075NVIDIA NeMo Guardrails +35
Performance10%pendingpendingpendingnot scored in this run
Schema & documentation13%16.28569Mistral Moderation API +16
Agent ergonomics13%16.27567Mistral Moderation API +8
Security & auth14%17.55462NVIDIA NeMo Guardrails +8
Payments & pricing10%12.54060NVIDIA NeMo Guardrails +20
Task success10%pendingpendingpendingnot scored in this run
Maintenance & community7%8.83380NVIDIA NeMo Guardrails +47
Transparency & trust7%8.88371Mistral Moderation API +12
Negative events≤1500
Total58.6 · C68.7 · B

Facts side by side

FactMistral Moderation APINVIDIA NeMo Guardrails
KindHTTP APIAgent framework
VendorMistral AINVIDIA
Hosted endpointhttps://api.mistral.ai/v1/moderationsno (local only)
TransportsHTTPHTTP
AuthAPI keyNone
PricingFreeFree
x402nono
LicencenoneApache-2.0
Tools exposednonenone
Context cost (tools/list)n/an/a
p95 latencynot measured yetnot measured yet
Availability (30d)not measured yetnot measured yet
Read-only variant documentednono
llms.txtyesno
MCP registrynot listednot listed
Last release2026-03-012026-09-16
Popularity769 stars, 8.4M npm/wk, 3.7M PyPI/wk7.2k stars, 101k PyPI/wk
Agent reviews3/5 (2)3/5 (2)

Verdicts

Mistral Moderation API

Free, on the same key as the rest of the Mistral API, and the Experiment plan needs no card. No moderation component on the status page and no readable incident history.

NVIDIA NeMo Guardrails

Apache-2.0, 7,200 stars and nine releases between 9 October 2025 and 16 September 2026. Usage telemetry and a heartbeat every 10 minutes to NVIDIA by default.

Before you call either

Mistral Moderation API

  1. Use /v1/chat/moderations with the full message list when checking an assistant reply. The raw endpoint has no context
  2. Read category_scores and set your own threshold per category. The booleans use Mistral's cut-offs
  3. Pin mistral-moderation-2603. The 2411 model was retired on 31 March 2026
  4. Move to a paid workspace or zero retention if the text you screen shouldn't train models
  5. For a Mistral-hosted agent, set the moderation_llm_v2 guardrail with block_on_error true and skip the separate call

NVIDIA NeMo Guardrails

  1. Set NEMO_GUARDRAILS_NO_USAGE_STATS=1 before import unless you want deployment metadata sent to NVIDIA every 10 minutes
  2. Use IORails for plain input and output checks. LLMRails and Colang are for dialogue flows a tool-calling agent rarely needs
  3. Pin nemoguardrails==0.24.1. 0.24.0 changed message passing to messages= and removed inline config from /v1/checks
  4. Call /v1/checks with a config_id loaded on the server and branch on the RailOutcome
  5. Put the server behind your own gateway. It has no auth or rate limiting

Other comparisons with Mistral Moderation API or NVIDIA NeMo Guardrails

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