The 3 Best Guardrails AI Alternatives in 2026

Lakera Guard is a security API you call before and after the model. It detects prompt injection, jailbreaks and adversarial instructions, sensitive-data exposure, harmful output and, for agents, unsafe tool use, including indirect injection that arrives through MCP-connected tools. Lakera claims sub-50 ms latency and coverage of 100+ languages, and its detectors are informed by Gandalf, its public prompt-injection game. Check Point announced its acquisition of Lakera in September 2025, and Lakera now sits inside Check Point's AI security portfolio. You can start free on the Community plan; production volumes, self-hosting and SLAs are quoted by sales.

• Purpose-built prompt-injection detection
• Sub-50 ms claimed latency
• Covers agent tool use and MCP injection

NeMo Guardrails sits between your app and the model and enforces rules you define: input rails screen or rewrite user messages, dialog rails keep the conversation on approved paths, retrieval rails filter RAG chunks, execution rails check the inputs and outputs of tools the model calls, and output rails block or fix responses. Rules are written in Colang, a Python-like modeling language. It ships jailbreak and injection detection, self-check moderation and hallucination rails, NVIDIA safety models, and integrations with services such as ActiveFence. It runs as a Python library or a server, works with LangChain, and is free under Apache-2.0 (latest release 0.24.1, September 2026). Usage telemetry is on by default and can be turned off.

• Backed by NVIDIA, Apache-2.0
• Rails for tool calls as well as chat
• Dialog control no classifier API offers

Bedrock Guardrails applies configurable safeguards to model inputs and outputs: content filters for hate, violence, sexual content and prompt attacks (text and images), denied topics you describe in plain language, word filters, PII and regex masking, contextual grounding checks for hallucination against a source, and Automated Reasoning checks against logical rules. Through the ApplyGuardrail API it works with any model, including OpenAI, Gemini and self-hosted models, not only those on Bedrock, and security teams can enforce one guardrail across an AWS organization. Pricing is per 1,000 text units (up to 1,000 characters each): content filters and denied topics $0.15, sensitive-information filters and contextual grounding $0.10, word filters and regex free, Automated Reasoning $0.17 per policy. Input and output are each charged.

• Published per-unit pricing
• Works with any model via ApplyGuardrail
• Org-wide enforcement across AWS accounts