Invariant Guardrails alternatives

Contextual guardrailing layer for agentic and MCP applications that sits at the LLM and MCP level. It enforces deterministic rules over tool calls, data flow, secrets, PII, code and loops. Full Invariant Guardrails 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 Invariant Guardrails →

  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 Invariant Guardrails →

  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 Invariant Guardrails →

  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 Invariant Guardrails →

  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 Invariant Guardrails →

  6. 6 Guardrails AI Guardrails & AI security ⚠ acquired — acquired by Harvey

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

    OSS ✓ Self-host ✓ Managed ? MCP ? ★ 7.6k released 2026-08-26 Apache-2.0 Compare with Invariant Guardrails →

  7. 7 Amazon Bedrock Guardrails Guardrails & AI security

    also in Guardrails & AI security

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

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

    also in Guardrails & AI security

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

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.