AWS Vector Databases in 2026: A Practical Selection Guide

With AWS's vector database landscape maturing in early 2026—highlighted by S3 Vectors' cost efficiency and Graviton5-powered instances delivering 20% compute savings—developers can now make truly practical decisions based on their stack and budget rather than chasing theoretical best practices. This comprehensive guide transforms the question from 'which database is best?' to 'which matches our needs and constraints?', providing a clear roadmap for RAG and semantic search implementations at scale.