AI guardrails developer tools
Every listing tagged guardrails, A to Z: 8 tools across 1 category. Listed in alphabetical order, not ranked.
Amazon Bedrock Guardrails
AWS's guardrails for generative AI: content filters with prompt attack detection, denied topics, word filters, PII filters and redaction, contextual grounding checks and Automated Reasoning checks. The ApplyGuardrail API checks any text without calling a Bedrock model. Content filters cost $0.15 per 1,000 text units of up to 1,000 characters; word filters and regex PII are free.
Azure AI Content Safety
Microsoft's guardrail APIs in Foundry: Prompt Shields catch user prompt attacks and instructions hidden in documents, next to text and image moderation, protected material and groundedness detection. 5,000 free text records a month, then $0.375 per 1,000 records of up to 1,000 characters in East US, with containers for disconnected use.
Google Cloud Model Armor
Google Cloud's guardrail service for LLM apps on any cloud: screens prompts and responses for prompt injection and jailbreaks, sensitive data through Sensitive Data Protection, and hate, harassment, sexual and dangerous content, including text inside PDFs and images, with templates to set thresholds. 2 million tokens a month free, then $0.10 per million tokens.
Guardrails AI
Open-source (Apache-2.0) Python framework for LLM guardrails: wrap model calls in Guards that run validators on input and output, from PII and toxicity checks to your own rules, and get structured data back. Validators come from Guardrails Hub as pip packages, and it runs in your code or as a REST server with guardrails start.
Lakera Guard (Check Point AI Guardrails)
Runtime guardrails API from Lakera, now part of Check Point and sold as Check Point AI Guardrails: one call to the Guard API screens prompts, documents and model output for prompt injection and jailbreaks, PII and data leakage, harmful content and unknown links, with tool allow and deny lists for agents. Free Community plan for 10,000 requests a month; Enterprise adds self-hosting.
Llama Guard 4 and Prompt Guard 2
Meta's open-weight guardrail models. Llama Guard 4 is a 12B multimodal classifier that labels prompts and responses, text and images, against 14 MLCommons hazard categories in 12 languages. Prompt Guard 2 comes in 86M and 22M sizes and flags prompt injection and jailbreaks. Free under the Llama 4 Community License; you host them.
NVIDIA NeMo Guardrails
NVIDIA's open-source (Apache-2.0) toolkit for programmable guardrails on LLM apps: input, output, dialog and retrieval rails that keep a bot on topic, detect jailbreaks and prompt injection, fact-check and moderate output. Configured in YAML and Colang, Python 3.10 to 3.13, works with LangChain.
OpenAI Moderation API
OpenAI's free moderation endpoint, a common first guardrail: omni-moderation-latest classifies text and images across 13 categories such as harassment, hate, illicit, self-harm, sexual and violence. It can also run inline on Responses API calls, tool-call arguments and outputs included. It moderates content; it does not detect prompt injection.