Native vector storage and querying in S3 — serverless, billion-vector scale.
Purpose-built vector storage inside Amazon S3: store and query up to two billion vectors per index across thousands of indexes per vector bucket, with S3's durability and elasticity and no clusters to manage. Frequent queries return in around 100ms and infrequent ones in under a second, and it plugs directly into Amazon Bedrock Knowledge Bases for RAG. You pay only for storage and queries.
Worth knowing
The first cloud object store with native vector support; its preview ingested 40B+ vectors before GA in December 2025.
Open-source serving engine for vector, lexical, and structured search at scale.
A big-data serving engine that combines approximate nearest-neighbor vector search, lexical search, structured filtering, and ML model inference in a single query, evaluated over data distributed across many nodes. Battle-tested at Yahoo scale, it is offered as a free Apache-2.0 engine you self-host, or as the managed Vespa Cloud — including an Enclave mode that runs inside your own AWS or GCP account.
Worth knowing
Powered Yahoo's search and ads for ~20 years before spinning out as an independent Apache-2.0 company in October 2023.
Distributed open-source vector DB built for billion-scale.
Cloud-native, Apache-2.0 vector database for similarity search at scale, powering RAG, semantic and multimodal search, and recommendations. Its distributed architecture separates storage and compute and supports many index types (HNSW, IVF, FLAT, DiskANN, SCANN) with quantization and mmap. Created by Zilliz, which offers the managed Zilliz Cloud.
Worth knowing
Often cited as the first open-source vector database; a graduated LF AI & Data Foundation project since 2021.
Embedded multimodal vector database on the Lance format.
An open-source retrieval engine for AI built on the Lance columnar format. It runs in-process alongside your app — no separate server — and stores, indexes, and searches vectors, metadata, and multimodal data (text, images, video) with vector, full-text, and SQL queries. A managed enterprise lakehouse tier scales the same engine to petabytes.
Worth knowing
Its CEO co-authored the pandas library; the YC-backed startup counts Midjourney as a customer.
Vector similarity search inside Postgres. The pragmatic default.
Postgres extension that adds a vector type plus exact and approximate nearest-neighbour search. Pairs naturally with Supabase, Neon, and any managed Postgres. The lowest-friction RAG backend if you already run Postgres.
Worth knowing
Created in 2021 by Andrew Kane, a solo open-source developer; it's now offered managed by AWS, Google Cloud, Azure, Supabase, and Neon.
Managed vector database. The industry-default serverless option.
Fully-managed vector DB built for production RAG and semantic search at scale. Serverless pricing, low-latency reads, integrations across every framework. Most Blokz-adjacent AI teams reach for it first.
Worth knowing
Founded in 2019 by Edo Liberty, formerly head of Amazon AI Labs; raised a $100M Series B at a $750M valuation in 2023.
Object-storage-backed vector DB. Serverless economics at scale.
Bills like S3 — cold rest, warm reads, no per-namespace minimums. Designed for very-large, mostly-cold vector workloads where you can't justify keeping every index in RAM. Operated by Notion in production.
Worth knowing
Built by two ex-Shopify engineers; it reached a ~$100M run-rate powering Cursor and Notion having raised under $1M.
Vector database written in Rust with a strong focus on filtering, payloads, and predictable latency at scale. Self-host on a single binary or use the managed cloud.
Worth knowing
Berlin-based, founded 2021; raised a $28M Series A led by Spark Capital in January 2024.
Open-source vector database with built-in vectorisers.
Cloud-native vector DB that can compute embeddings inline — pass raw text in, store vectors out. Strong hybrid (BM25 + vector) search; self-hostable or managed.
Worth knowing
Founded in Amsterdam in 2019 under the name SeMI Technologies; raised a $50M Series B led by Index Ventures in 2023.
The low-friction starting point — Chroma runs embedded inside your Python process or as a hosted service. Great for prototypes and small-to-medium RAG apps; upgrade to a managed option when you outgrow it.
Worth knowing
Raised an $18M seed (Quiet Capital, 2023) with angels including Naval Ravikant, Guillermo Rauch, and Amjad Masad.