Amazon Bedrock is a fully managed service from AWS that provides API-based access to foundation models from leading AI companies including Anthropic, AI21 Labs, Cohere, Meta, Mistral AI, Stability AI, and Amazon's own models. Rather than managing infrastructure, model hosting, or model training from scratch, developers can access state-of-the-art foundation models through a single unified API, customize them with proprietary data through fine-tuning or RAG, and build generative AI applications at scale with enterprise-grade security and privacy controls. Bedrock abstracts away the complexity of provisioning compute, managing model lifecycles, and securing inference endpoints, enabling teams to focus on application logic and business value. A key mental model to keep in mind: Bedrock is a model marketplace + inference runtime + customization toolkit — it's not a single model but an orchestration layer that lets you compare, customize, and operationalize many models using consistent tooling, with built-in safeguards like Guardrails to enforce compliance and responsible AI policies across all your generative AI workloads.