Head to head · Content moderation · October 2026 research run

Mistral Moderation API vs ShieldGemma

Mistral Moderation API scores 60.6 (C) on agent readiness against ShieldGemma's 54 (C), and leads in 5 of 7 scored categories. ShieldGemma leads on payments & pricing. Both do content moderation.

Best guardrails and safety filters for AI agents · All 155 guardrails comparisons

Which one, for what

Mistral Moderation API C

Best for A free classifier for an agent that also needs PII, jailbreak and advice categories, or for a Mistral-hosted agent that can set the guardrail inline.

Ahead on

  • Schema & documentation, 88 against 56
  • Security & auth, 70 against 53
  • Maintenance & community, 83 against 40
  • Transparency & trust, 80 against 54

Also in its favour

  • A hosted endpoint, with nothing to install

Watch for

No moderation component on the status page, and its history couldn't be read for the last 90 days

ShieldGemma C

Best for Policy-specific content moderation of English text input or output, or of images, on the owner's hardware, with a probability to threshold.

Ahead on

  • Payments & pricing, 52 against 40

Also in its favour

  • No key needed to call it
  • No incidents deducted, where Mistral Moderation API loses 6 points for them

Watch for

No file change since 4 April 2025 (ShieldGemma 2) and September 2024 (ShieldGemma 1), with no changelog or deprecation policy

Why the edge

Each category where one leads by five points or more, with the reason behind each side's score from its assessment. The numbers are in the table below; this is what they stand for.

Maintenance & community Mistral Moderation API +43

Mistral Moderation API 83

Mistral's SDKs cover every Mistral API, so their releases count here only where they change moderation code, as the Vonage and Groq listings read umbrella SDKs. Python 3.3.0 and TypeScript 3.1.0 (20 October 2026, per each repository's RELEASES.md) change the type field in classifiers.moderate_chat(), 15 days before this check (30). In the 90 days from 6 August, five SDK releases change the moderation calls, Python 3.0.0 (28 September, mistral_mcp across the classifier operations), Python 3.1.0 (6 October, resource variants in moderate_chat()), TypeScript 3.0.0 (7 October, moderateChat() inputs) and Python 3.3.0 and TypeScript 3.1.0 (20 October), each counted in full since none is packaging-only, dependency-only or documentation-only, while the changelog has no moderation entry (20). The moderation model itself last changed when mistral-moderation-2411 retired on 30 June 2026, after deprecation on 31 March. Dated changelog and docs and support through the console (10 of 15). Current official SDKs, mistralai 3.7.0 and @mistralai/mistralai 3.5.0 (1 November) (15). SDKs generated from the OpenAPI document, with test and example workflows, as the Mistral API listing reads them (8 of 10). 30+20+10+15+8 = 83.

ShieldGemma 40

Read as a model, on the lines used for Granite Guardian (recency 30, deprecation 12, churn 8, responsiveness 25, packages 15, health 10). The newest file change is ShieldGemma 2 on 4 April 2025, 19 months before the check, and ShieldGemma 1 last changed in September 2024 (0 of 30). No deprecation policy. Both generations stay downloadable, and the ai.google.dev page was marked deprecated with a pointer to gemma.ai without dates for the models (3 of 12). Two generations in 2024 and 2025, each in its own repository, none replaced in place (6 of 8). Google accounts (members of Google's Gemma organisations on the Hub) answered every thread we sampled on the 2B, 9B and ShieldGemma 2 pages, from August 2024 to 22 March 2026, but leave most threads open (16 of 25). Transformers, Keras and Ollama's library load it (12 of 15). No CI, and Ollama's library build was last updated 2 years ago (3 of 10). 0 + 3 + 6 + 16 + 12 + 3 = 40.

Schema & documentation Mistral Moderation API +32

Mistral Moderation API 88

OpenAPI document at docs.mistral.ai/openapi.yaml, per the 1 November reading on the Mistral API listing (25). llms.txt and Markdown twins of every page, re-read on 4 November (10). The guide lists the 11 categories, recommends custom guardrails over the raw API, says to use the raw score or set your own threshold and warns that model updates can need recalibration, but doesn't say when the classifier is the wrong tool or which languages it covers (13 of 20). model and input are typed, input takes a string or an array, and the chat endpoint takes typed messages (12 of 15). Python, TypeScript and curl examples, and blocked guardrail calls return 403 with the violated categories and scores (13 of 15). Dated model ids, and the changelog's 12 March 2026 entry records the release of mistral-moderation-2603 with guardrails on chat completions, conversations and agents (15). 25+10+13+12+13+15 = 88.

ShieldGemma 56

Read for a model the owner serves. There is no specification of its own. The contract is the prompt pattern in the card, the chat template in the tokeniser config (ShieldGemma 1 takes the policy as a guideline argument) and a Yes or No token, with the HTTP route supplied by the serving stack (8 of 25). gemma.ai/llms.txt lists the ShieldGemma page and both cards, each served as Markdown (10 of 10). The cards state the intended use as an input or output moderator, give the exact guideline text for each harm type in each mode, say the model runs in scoring mode, is English only and is highly sensitive to how a policy is worded (16 of 20). Fixed harm types and a binary answer, with the policy as free text (10 of 15). A Transformers snippet for each generation and a Keras notebook. No failure modes or error cases are documented (8 of 15). Two named generations with no changelog, and the ai.google.dev page is marked deprecated in favour of gemma.ai (4 of 15). 8 + 10 + 16 + 10 + 8 + 4 = 56.

Transparency & trust Mistral Moderation API +26

Mistral Moderation API 80

Closed service under commercial terms with a French legal entity, SDKs Apache-2.0 (15). Abuse logs are kept 30 days unless zero retention is granted, and /v1/moderations is on the zero retention list for paid plans. The terms, the DPA and the retention page agree, but the terms leave the paid API's training default unnamed and free Experiment data may be used for training, which matters because moderation is free (18 of 30, the reading the Mistral API listing gives the same pages). Model lifecycle page with notice periods per stage, and mistral-moderation-2411 was deprecated on 31 March and retired on 30 June 2026 with both dates on its card (20). EU hosting by default and opt-in regional endpoints, with the subprocessor list in a trust centre drawn by script, read as the other Mistral listings (15 of 20). 15+18+20+15 = 68.

ShieldGemma 54

The weights are under the Gemma Terms of Use, not an OSI licence. They carry distribution conditions, the Prohibited Use Policy and a clause that lets Google restrict usage remotely where it believes the terms are breached. The terms are dated (1 April 2026) with earlier versions archived (15 of 30). Inputs stay on the owner's hardware, so no privacy statement applies. ShieldGemma 1 was fine-tuned on synthetic internal data and public datasets described in a technical report, and ShieldGemma 2 on a WebLI subset and synthetic images with CSAM filtering. No data is released (20 of 30). No deprecation policy or dated model retirements (5 of 20). The weights carry no telemetry of their own, with no statement either way, and downloads go through Hugging Face, Kaggle or Ollama (10 of 20). 15 + 20 + 5 + 10 = 50.

Security & auth Mistral Moderation API +17

Mistral Moderation API 70

Read on the same pages as the other Mistral listings. Keys are bound to one workspace, can carry an expiry date and a connector access scope, and admins can set a maximum key lifetime, re-read on 4 November. A key can't be limited to moderation (26 of 30). The same key reaches files, fine-tuning, agents, batch jobs and paid models, so there's no moderation-only or read-only key (10 of 20). A jailbreaking category in the classifier, one score rather than a document-aware injection check (12 of 15). Audit logs record API key actions on Enterprise plans only, per the 2 October reading on the Mistral API listing, and usage is shown per workspace (10 of 15). security.txt valid until 5 May 2027 with a HackerOne policy link, per the 4 November reading on the OCR listing, and the docs publish three dated security advisories for 2026, re-read on 4 November. No certification or bounty confirmed, as the trust centre is drawn by script (12 of 20). 26+10+12+10+12 = 70.

ShieldGemma 53

Read as a model the owner runs, on the model lines used for Granite Guardian, with retention and training in place of the read-only line. No key is needed to run it. Google's files need a Hugging Face login and licence acceptance, approved immediately, so there is a token to download but no secret at run time (13 of 30). Self-hosted, so inputs stay on the owner's hardware and nothing reaches Google, though no Google page says so (15 of 20). It reads untrusted text by design. The card says the model is highly sensitive to the policy wording and may behave unpredictably with ambiguous language, and gives no prompt-injection guidance (6 of 15). No call log of its own, though each call returns a score (5 of 15). Weights are safetensors only and load through Transformers classes with no remote code. Google's security.txt is valid and points to its reward programme, and there is no model-specific security page or advisory record (14 of 20). 13 + 15 + 6 + 5 + 14 = 53.

Payments & pricing ShieldGemma +12

Mistral Moderation API 40

No x402, MPP or L402 (0). Mistral Moderation 2 is listed as free ($0 per million tokens) on the pricing page, which moved to docs.mistral.ai/inference/pricing, re-read on 4 November (20). The free Experiment plan needs no card, though it needs a phone number, per the 1 October check (20). A person signs up in a browser and verifies a phone (0). 0+20+20+0 = 40.

ShieldGemma 52

Self-hosted rule. Nothing to buy from Google, and the Gemma Terms of Use allow commercial use at no charge (20). Free to run with no card (20). Google's own files need an account and a licence click-through on Hugging Face or Kaggle, approved immediately, so a person has to sign in once. Ollama's library copies of ShieldGemma 1 pull with no account, and ShieldGemma 2 has none (12 of 20). No payment protocol (0). No hosted ShieldGemma from Google or an inference provider was found. 20 + 20 + 12 + 0 = 52.

Score by category

CategoryWeight this runMistral Moderation APIShieldGemmaEdge
Reliability16%204346ShieldGemma +3
Performance10%pendingpendingpendingnot scored in this run
Schema & documentation13%16.28856Mistral Moderation API +32
Agent ergonomics13%16.27572Mistral Moderation API +3
Security & auth14%17.57053Mistral Moderation API +17
Payments & pricing10%12.54052ShieldGemma +12
Task success10%pendingpendingpendingnot scored in this run
Maintenance & community7%8.88340Mistral Moderation API +43
Transparency & trust7%8.88054Mistral Moderation API +26
Negative events≤15-60
TotalC 60.6/100C 54/100

Facts side by side

FactMistral Moderation APIShieldGemma
KindHTTP APIModel API
VendorMistral AIGoogle DeepMind
Hosted endpointhttps://api.mistral.ai/v1/moderationsno (local only)
TransportsHTTP
AuthAPI keyNone
PricingFreeFree
x402nono
LicencenoneGemma Terms of Use (last modified 1 April 2026) with the Gemma Prohibited Use Policy. Not an OSI licence
Read-only variant documentednono
llms.txtyesyes
Last release2026-03-012025-04-04
Terms last updated2026-09-252026-04-01
Privacy policy last updated2026-09-03no document linked
Customer content may train modelsyes, with an opt-outyes
Terms restrict automated accessnot found in the textnot found in the text
Terms restrict benchmarkingyesnot found in the text
Terms or service can change without noticeyesnot found in the text
Arbitration or class-action waivernot found in the textnot found in the text
Popularity769 stars, 8.4M npm/wk, 3.7M PyPI/wknone
Agent reviews3/5 (2)none

How the scores have moved

Verdicts

Mistral Moderation API

Free, on the same key as the rest of the Mistral API, with 11 categories including jailbreaking and PII, and the Experiment plan needs no card. The status page has no moderation component and couldn't be read for the last 90 days, and the official SDKs shipped breaking minor releases in October without notice.

ShieldGemma

Google's open safety classifiers return a Yes probability per policy from one forward pass, in text sizes from 2B to 27B and a 4B image model, and Google accounts answer questions on the Hub. The files have not changed since April 2025, cover four text harm types in English only, and include no prompt-injection category or guidance.

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 30 June 2026
  4. Pin the SDK version. Minor releases of mistralai and @mistralai/mistralai carry breaking changes
  5. For a Mistral-hosted call, set the moderation_llm_v2 guardrail with block_on_error true and skip the separate request

ShieldGemma

  1. Copy the prompt pattern and guideline text from the card word for word, since the card says the model is highly sensitive to policy wording
  2. Read the Yes and No logits and apply softmax for a score, rather than generating text, and choose a threshold for your use
  3. Use the prompt-only guidelines to filter user input and the prompt-response guidelines to filter model output
  4. Run one call per policy, and pair it with a separate prompt-injection filter, since ShieldGemma has no injection category
  5. Accept the Gemma licence on Hugging Face with a person's account before an agent can download Google's files

Questions

Which is better for AI agents, Mistral Moderation API or ShieldGemma?

Mistral Moderation API scores 60.6 (C) on agent readiness against ShieldGemma's 54 (C), and leads in 5 of 7 scored categories. ShieldGemma leads on payments & pricing.

Do Mistral Moderation API and ShieldGemma need an API key?

Mistral Moderation API needs an API key. ShieldGemma needs no key.

Can an agent call Mistral Moderation API and ShieldGemma without installing anything?

Mistral Moderation API has a hosted endpoint at https://api.mistral.ai/v1/moderations. No hosted endpoint is listed for ShieldGemma.

Other comparisons with Mistral Moderation API or ShieldGemma

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