NeMo Guardrails
NVIDIA's open-source toolkit for adding programmable safety, topic, and dialog rails to LLM applications. Define rules in Colang DSL to prevent off-topic responses, enforce output formats, and guard against prompt injection. Standard in enterprise LLM deployments.
LangChain
Most widely used framework for building LLM applications. Chains, agents, RAG pipelines, and deep integrations with 300+ tools.