Cloud AI: Machine Learning & Generative AI

Embeddings & Nearest-Neighbor Search

Embeddings turn meaning into vectors, and nearest-neighbor indexes find similar ones in milliseconds among millions. This is the engine of semantic search and RAG.

Multicloud AI & ERP / Cloud AI: Machine Learning & Generative AI

Embeddings & Nearest-Neighbor Search: diagram comparing AWS, Azure and Google Cloud
How semantic search finds a match, and how AWS, Azure and Google Cloud each implement it.

Why it matters

Keyword search misses synonyms and intent. Embedding-based search finds documents that mean the same thing even when the words differ, which is why it sits behind almost every AI assistant and modern search experience.

How it works

From text to nearest neighbors

An embedding model turns a text chunk or image into a vector of numbers. Similar meanings land close together. An approximate nearest neighbor (ANN) index such as HNSW finds the closest vectors without comparing every one, trading a little recall for large speed gains.

Re-ranking improves the top results

The fastest retrieval is not always the most precise. A re-ranker model reorders the top candidates for relevance, often lifting answer quality more than changing the main model.

AWS, Azure and Google Cloud compared

AWSAzureGoogle Cloud
Embedding modelsTitan, Cohere Embed (Bedrock)OpenAI embeddings, Cohere (Foundry)Gemini embeddings
ANN searchOpenSearch k-NNAzure AI Search HNSWVector Search (ScaNN)
Low-cost vector storageS3 VectorsCosmos DB DiskANNAlloyDB ScaNN
Re-rankingBedrock rerank modelsSemantic rankerRanking API
CompressionBinary embeddingsScalar and binary quantizationOutput dimensionality control

What makes each cloud different

AWS

Bedrock offers Titan and Cohere embedding models and rerank models, OpenSearch provides HNSW and IVF indexes with filters, and S3 Vectors stores very large vector sets at low cost.

Azure

Azure AI Search supports vector fields with HNSW, scalar and binary quantization to cut storage, and a semantic ranker that re-orders hybrid results. Cosmos DB adds DiskANN vector search inside operational data.

Google Cloud

Gemini embeddings support task types that distinguish queries from documents, improving matching. Vector Search uses ScaNN at very large scale, and the Ranking API re-ranks retrieved passages.

Design decisions that matter

  1. 01One embedding model per index

    Never mix models in the same index.

  2. 02Version the index

    Re-embed into a new index, then switch.

  3. 03Add a re-ranker

    Cheap way to improve top results.

  4. 04Compress where possible

    Quantization cuts cost with little quality loss.

Common mistakes we see

  • Changing models in place. Old and new vectors are not comparable.
  • No evaluation set. You cannot tell whether retrieval improved.
  • Chunks that are too large. Relevant sentences drown in noise.

A practical 30-day plan

  1. Week 1

    Build an evaluation set of real queries and correct documents.

  2. Week 2

    Compare two embedding models and chunk sizes.

  3. Week 3

    Add a re-ranker and measure the gain.

  4. Week 4

    Apply compression and set up index versioning.

How NTS helps

NTS builds semantic search on AWS, Azure and Google Cloud, choosing embedding models, tuning chunking and ranking and measuring retrieval quality with real evaluation sets.

What you get

  • Embedding model selection and testing
  • Approximate nearest-neighbor indexes tuned for recall and speed
  • Pipelines to embed and refresh content
  • Retrieval quality metrics

Typical outcomes

  • More relevant search and recommendations
  • Fast queries at large scale
  • Better grounding for AI assistants

How we work with you

  1. 1Assess

    A focused review of your embeddings and semantic search across AWS, Azure and Google Cloud. We look for the gaps we find most often: changing models in place, no evaluation set and chunks that are too large.

  2. 2Design

    A target architecture and roadmap built on the decisions that matter most: one embedding model per index, version the index, add a re-ranker and compress where possible.

  3. 3Build

    Hands-on delivery alongside your team. We build an evaluation set of real queries and correct documents, compare two embedding models and chunk sizes, add a re-ranker and measure the gain, and finally apply compression and set up index versioning.

  4. 4Run and improve

    We refresh embeddings, re-tune indexes and test new embedding models over time.

Why teams choose NTS for embeddings and semantic search

  • Recall and speed balanced

    We tune indexes to find the right results quickly.

  • Measured relevance

    We prove search quality with test sets.

  • Fits your stack

    Embeddings integrate with your existing databases and search.

Book a free 30-minute review

Talk to an NTS architect about your embeddings and semantic search on AWS, Azure and Google Cloud.