Guardrails AI alternatives

Open-source guardrails framework plus the Guardrails Hub of validators that detect policy violations, hallucinations and data leakage in LLM and agent outputs at runtime. Harvey announced its acquisition of Guardrails AI on Sep 8, 2026. Full Guardrails AI record →

  1. 1 Presidio Guardrails & AI security

    also in Guardrails & AI security · also open source · also self-hostable

    OSS ✓ Self-host ✓ Managed ? MCP ? ★ 12k released 2026-10-29 MIT Compare with Guardrails AI →

  2. 2 NVIDIA NeMo Guardrails Guardrails & AI security

    also in Guardrails & AI security · also open source · also self-hostable

    OSS ✓ Self-host ✓ Managed ? MCP ? ★ 7.4k released 2026-10-29 Apache-2.0 Compare with Guardrails AI →

  3. 3 PyRIT Guardrails & AI security

    also in Guardrails & AI security · also open source · also self-hostable

    OSS ✓ Self-host ✓ Managed ? MCP ? ★ 4.7k released 2026-10-29 MIT Compare with Guardrails AI →

  4. 4 Meta Llama Protections (Llama Guard, Prompt Guard, LlamaFirewall) Guardrails & AI security

    also in Guardrails & AI security · also open source · also self-hostable

    OSS ✓ Self-host ✓ Managed ? MCP ? ★ 4.5k released 2026-10-12 Llama 3.2 Community License (Llama Guard /… Compare with Guardrails AI →

  5. 5 Arthur Engine Guardrails & AI security

    also in Guardrails & AI security · also open source · also self-hostable

    OSS ✓ Self-host ✓ Managed ? MCP ? ★ 93 released 2026-10-28 MIT Compare with Guardrails AI →

  6. 6 Invariant Guardrails Guardrails & AI security ⚠ acquired — acquired by Snyk

    also in Guardrails & AI security · also open source · also self-hostable

    OSS ✓ Self-host ✓ Managed ? MCP ✓ ★ 475 released 2026-01-12 Apache-2.0 Compare with Guardrails AI →

  7. 7 Amazon Bedrock Guardrails Guardrails & AI security

    also in Guardrails & AI security

    OSS — Self-host ? Managed ? MCP ? proprietary Compare with Guardrails AI →

  8. 8 Azure AI Content Safety Prompt Shields Guardrails & AI security

    also in Guardrails & AI security

    OSS — Self-host ? Managed ? MCP ? proprietary Compare with Guardrails AI →

Ranked by shared memory design (storage, retrieval, conflict handling, memory unit), same section and shared must-haves (open source, self-hosting, MCP), with adoption as a tie-breaker. ✓ confirmed · — no · ? not in the catalog yet. Want picks for your own requirements? Use the chooser. Checking a whole project? Check your stack.