S4 Embed - Vector Search FinOps Gateway

S4 Embed is a Vector Search FinOps layer: it helps you find and run a low-cost vector-search configuration that meets your recall target. Quantization (binary for an up-to-32x smaller in-RAM ANN graph, int8 residual for about 4x smaller on-disk vectors) plus a two-stage search (coarse Hamming shortlist then exact rescore) reduce RAM while you tune the over-fetch/rescore operating point to hold recall. On a 30k-vector benchmark, binary Hamming + float rescore reached recall@10 of 0.987 at over-fetch 50 and 0.995-0.996 at over-fetch 100 on OpenSearch and pgvector, 1.000 on Qdrant, and 0.976 on Milvus (tune per workload) - all at the 32x RAM reduction. Recall scales with over-fetch as the corpus grows, so the operating point is chosen per workload. The pipeline is store-agnostic across OpenSearch, pgvector, Qdrant, and Milvus.

The FinOps tools are the product. s4embed prove estimates the recall/cost/latency frontier on your vectors using the in-process quantization/rescore model and returns a recommended config. s4embed compare measures live ANN recall across OpenSearch, pgvector, Qdrant, and Milvus for your corpus and queries. s4embed tune emits a deployable config meeting a declared recall + latency + RAM budget. A gateway shadow mode dual-writes and shadow-compares live reads so you can watch the compressed path reproduce your primary before cutting over; use compare plus shadow mode to validate before any cutover, and s4embed drift watches embedding drift and recall and recommends re-tuning.

It runs as a standard Amazon Linux 2023 AMI behind your own load balancer, in your own VPC - your data and your vector database never leave your account, and there is no lock-in. The gateway supports API-key auth when configured, request size and concurrency caps, a readiness probe that fails closed on billing or store problems, and Prometheus metrics. Billing is usage-metered through your AWS bill: you pay per text embedded, document indexed, and search served, reported hourly via the AWS Marketplace Metering Service.