Azure AI Search

Azure AI Search is a fully managed, cloud-hosted service that connects your data to AI. The service unifies access to enterprise and web content so agents and LLMs can use context, chat history, and multi-source signals to produce reliable, grounded answers.

Classic Search

Traditional search with full-text, vector, and hybrid queries

Agentic Retrieval

LLM-assisted multi-query retrieval for agent workflows

AI Enrichment

Extract and structure content with AI processing

Enterprise Ready

Security, compliance, and scale for production workloads

What is Azure AI Search?

Common use cases include classic search for traditional search applications and agentic retrieval for modern retrieval-augmented generation (RAG) scenarios. This makes Azure AI Search suitable for both enterprise and consumer scenarios.

Key Capabilities

When you create a search service, you unlock:

Search Engines
Content Processing
Enterprise Features

Classic search for single requests
Agentic retrieval for parallel, iterative, LLM-assisted search
Full-text search with BM25 ranking
Vector search with similarity matching
Hybrid search combining text and vectors
Multimodal queries over text and images

Why Use Azure AI Search?

Ground AI Responses

Provide agents and chatbots with accurate, context-aware responses grounded in your data.

Multi-Source Access

Connect to Azure Blob Storage, Cosmos DB, SharePoint, OneLake, and more.

Intelligent Processing

Enrich content with AI skills for chunking, embedding, and transformation.

Hybrid Search

Combine full-text and vector search to balance precision and recall.

Multimodal Search

Query content containing both text and images in a single pipeline.

Enterprise Security

Implement document-level access control, private networks, and compliance.

Classic Search

Classic search is an index-first retrieval model for predictable, low-latency queries.

How It Works

Create an Index

Define the schema with fields, data types, and attributes.

{
  "name": "products-index",
  "fields": [
    {"name": "id", "type": "Edm.String", "key": true},
    {"name": "title", "type": "Edm.String", "searchable": true},
    {"name": "description", "type": "Edm.String", "searchable": true},
    {"name": "category", "type": "Edm.String", "filterable": true},
    {"name": "price", "type": "Edm.Double", "filterable": true},
    {"name": "vector", "type": "Collection(Edm.Single)", "dimensions": 1536}
  ]
}

Load Content

Use push or pull methods to populate the index.Push Method (direct upload):

from azure.search.documents import SearchClient

search_client = SearchClient(endpoint, index_name, credential)

documents = [
    {
        "id": "1",
        "title": "Azure AI Search",
        "description": "Powerful search service",
        "category": "AI Services",
        "price": 0.0
    }
]

result = search_client.upload_documents(documents)

Pull Method (indexer):

from azure.search.documents.indexes import SearchIndexerClient
from azure.search.documents.indexes.models import (
    SearchIndexer,
    SearchIndexerDataSourceConnection
)

# Create data source
data_source = SearchIndexerDataSourceConnection(
    name="myblob-datasource",
    type="azureblob",
    connection_string="DefaultEndpointsProtocol=https;...",
    container=SearchIndexerDataContainer(name="documents")
)

# Create indexer
indexer = SearchIndexer(
    name="myblob-indexer",
    data_source_name="myblob-datasource",
    target_index_name="products-index"
)

indexer_client.create_or_update_indexer(indexer)

Query the Index

Execute searches with various query types.

# Full-text search
results = search_client.search(
    search_text="machine learning",
    select=["title", "description"],
    top=10
)

# Vector search
results = search_client.search(
    vector_queries=[VectorizedQuery(
        vector=query_embedding,
        k_nearest_neighbors=5,
        fields="vector"
    )]
)

# Hybrid search
results = search_client.search(
    search_text="AI services",
    vector_queries=[VectorizedQuery(
        vector=query_embedding,
        k_nearest_neighbors=5,
        fields="vector"
    )],
    top=10
)

Query Types

Full-Text Search

Traditional keyword-based search with BM25 ranking.Features:

Tokenization and lexical analysis
Fuzzy matching and wildcards
Phrase queries and proximity search
Boolean operators (AND, OR, NOT)
Field-weighted scoring

results = search_client.search(
    search_text='neural networks',
    query_type='full',
    search_fields=['title', 'content'],
    select=['title', 'content', 'author'],
    top=10
)

Vector Search

Similarity-based search using embedding vectors.Features:

Semantic similarity matching
Support for multiple vector fields
Exhaustive or approximate (HNSW) algorithms
Configurable distance metrics (cosine, dot product, Euclidean)

from azure.search.documents.models import VectorizedQuery

# Generate query embedding
query_vector = openai_client.embeddings.create(
    input="deep learning tutorials",
    model="text-embedding-ada-002"
).data[0].embedding

# Vector search
results = search_client.search(
    vector_queries=[VectorizedQuery(
        vector=query_vector,
        k_nearest_neighbors=10,
        fields="content_vector"
    )]
)

Hybrid Search

Combine text and vector search for best results.Features:

Reciprocal Rank Fusion (RRF) for result merging
Balanced precision and recall
Configurable weight between text and vector
Optimal for RAG applications

results = search_client.search(
    search_text="artificial intelligence",
    vector_queries=[VectorizedQuery(
        vector=query_vector,
        k_nearest_neighbors=50,
        fields="content_vector"
    )],
    top=10
)

Semantic Search

Microsoft’s semantic ranker for improved relevance.Features:

Deep learning re-ranking
Semantic captions and highlights
Query understanding
Multilingual support

results = search_client.search(
    search_text="how to train neural networks",
    query_type='semantic',
    semantic_configuration_name='my-semantic-config',
    query_caption='extractive',
    top=10
)

for result in results:
    print(f"Title: {result['title']}")
    print(f"Caption: {result['@search.captions'][0].text}")
    print(f"Score: {result['@search.reranker_score']}")

Agentic Retrieval

Agentic retrieval is a multi-query pipeline designed for complex agent-to-agent workflows.

Knowledge Bases

A knowledge base represents a complete domain of knowledge:

from azure.search.documents.indexes.models import (
    SearchIndex,
    KnowledgeBase,
    KnowledgeSource
)

# Create knowledge base
kb = KnowledgeBase(
    name="company-knowledge",
    description="Corporate documentation and policies",
    knowledge_sources=[
        KnowledgeSource(
            name="sharepoint-docs",
            type="sharepoint",
            connection_string="...",
            site_url="https://company.sharepoint.com"
        ),
        KnowledgeSource(
            name="azure-storage",
            type="azureblob",
            connection_string="...",
            container_name="documents"
        )
    ],
    reasoning_effort="medium",  # low, medium, high
    include_citations=True
)

kb_client.create_or_update(kb)

Query Flow

Planning

LLM analyzes the query and creates a retrieval plan.

Decomposition

Break complex queries into focused subqueries.

Parallel Retrieval

Execute subqueries across multiple knowledge sources simultaneously.

Semantic Reranking

Apply semantic understanding to improve result quality.

Results Merging

Combine and deduplicate results from all sources.

Response Generation

Return answer, sources, and activity log optimized for agents.

Agent Integration

from azure.ai.projects import AIProjectClient

# Query knowledge base through agent
agent = project_client.agents.create(
    model="gpt-4",
    instructions="Answer questions using company knowledge.",
    tools=[{
        "type": "knowledge_base",
        "knowledge_base_id": kb.id
    }]
)

thread = project_client.agents.create_thread()
message = project_client.agents.create_message(
    thread.id,
    "user",
    "What is our return policy?"
)

run = project_client.agents.create_run(thread.id, agent.id)
response = project_client.agents.wait_for_run(thread.id, run.id)

# Response includes:
# - Grounded answer
# - Source citations
# - Activity log
# - Confidence scores

AI Enrichment

AI enrichment uses skills to extract and transform content during indexing:

Built-in Skills

Text Skills

Text splitting (chunking)
Language detection
Key phrase extraction
Entity recognition
Sentiment analysis
PII detection

Vision Skills

OCR (text extraction)
Image analysis
Object detection
Brand detection
Face detection
Handwriting recognition

AI Skills

Azure OpenAI embeddings
Multimodal embeddings
Text translation
Custom models

Utility Skills

Conditional logic
Document extraction
Shaper (structure data)
Merge fields

Skillset Example

from azure.search.documents.indexes.models import (
    SearchIndexerSkillset,
    SplitSkill,
    AzureOpenAIEmbeddingSkill,
    EntityRecognitionSkill
)

skillset = SearchIndexerSkillset(
    name="document-enrichment",
    description="Extract and vectorize content",
    skills=[
        # Split text into chunks
        SplitSkill(
            context="/document",
            text_split_mode="pages",
            maximum_page_length=2000,
            page_overlap_length=500,
            inputs=[{"name": "text", "source": "/document/content"}],
            outputs=[{"name": "textItems", "target_name": "chunks"}]
        ),
        # Generate embeddings
        AzureOpenAIEmbeddingSkill(
            context="/document/chunks/*",
            resource_uri="https://your-openai.openai.azure.com",
            deployment_id="text-embedding-ada-002",
            inputs=[{"name": "text", "source": "/document/chunks/*"}],
            outputs=[{"name": "embedding", "target_name": "vector"}]
        ),
        # Extract entities
        EntityRecognitionSkill(
            context="/document",
            categories=["Person", "Organization", "Location"],
            inputs=[{"name": "text", "source": "/document/content"}],
            outputs=[{"name": "entities", "target_name": "entities"}]
        )
    ]
)

indexer_client.create_or_update_skillset(skillset)

Integrated Vectorization

Automate embedding generation during indexing:

# Configure vectorizer
from azure.search.documents.indexes.models import (
    AzureOpenAIVectorizer,
    VectorSearch,
    VectorSearchProfile
)

vectorizer = AzureOpenAIVectorizer(
    name="my-vectorizer",
    azure_open_ai_parameters={
        "resource_uri": "https://your-openai.openai.azure.com",
        "deployment_id": "text-embedding-ada-002",
        "api_key": "your-key"
    }
)

# Add to index
index = SearchIndex(
    name="auto-vectorized-index",
    fields=[
        SimpleField(name="id", type="Edm.String", key=True),
        SearchableField(name="content", type="Edm.String"),
        SearchField(
            name="content_vector",
            type="Collection(Edm.Single)",
            vector_search_dimensions=1536,
            vector_search_profile_name="my-profile"
        )
    ],
    vector_search=VectorSearch(
        profiles=[VectorSearchProfile(
            name="my-profile",
            vectorizer_name="my-vectorizer"
        )],
        vectorizers=[vectorizer]
    )
)

Security Features

Document-Level Security

Implement fine-grained access control:

# Index documents with security fields
documents = [
    {
        "id": "doc1",
        "content": "Confidential information",
        "security_filter": ["group1", "user123"]
    }
]

search_client.upload_documents(documents)

# Query with security filter
user_groups = ["group1", "group2"]
filter_expression = " or ".join(
    [f"security_filter/any(g: g eq '{group}')" for group in user_groups]
)

results = search_client.search(
    search_text="confidential",
    filter=filter_expression
)

Network Security

Private Endpoints
Firewall Rules
Managed Identity

Connect to search service over private network:

Azure Private Link integration
No public internet exposure
Network traffic stays on Azure backbone
Compatible with VNet peering

Restrict access by IP address:

from azure.mgmt.search import SearchManagementClient

# Configure IP rules
search_service = search_mgmt_client.services.update(
    resource_group_name="my-rg",
    search_service_name="my-search",
    service={
        "network_rule_set": {
            "ip_rules": [
                {"value": "40.76.54.131"},
                {"value": "18.43.32.0/24"}
            ]
        }
    }
)

Authenticate without keys:

from azure.identity import DefaultAzureCredential
from azure.search.documents import SearchClient

credential = DefaultAzureCredential()
search_client = SearchClient(
    endpoint="https://my-search.search.windows.net",
    index_name="my-index",
    credential=credential
)

Monitoring and Optimization

Search Analytics

Track usage patterns and optimize:

from azure.monitor.query import LogsQueryClient

logs_client = LogsQueryClient(credential)

# Query search logs
query = """
AzureDiagnostics
| where ResourceType == "SEARCHSERVICES"
| where OperationName == "Query.Search"
| summarize 
    QueryCount = count(),
    AvgDuration = avg(DurationMs),
    AvgResultCount = avg(ResultCount)
  by SearchText = Query_s
| order by QueryCount desc
| take 20
"""

response = logs_client.query_workspace(
    workspace_id="your-workspace-id",
    query=query,
    timespan=timedelta(days=7)
)

Performance Tuning

Relevance Tuning

Improve search result quality:

Scoring Profiles: Boost fields or apply functions
Synonym Maps: Handle terminology variations
Custom Analyzers: Language-specific tokenization
Semantic Ranking: Deep learning re-ranking

Scale Configuration

Optimize for throughput and storage:

Replicas: Handle more queries per second
Partitions: Store more documents
Auto-scaling: Adjust capacity based on load
Index Optimization: Reduce field count and analyzers

Pricing Tiers

Tier	Storage	Replicas	Partitions	Use Case
Free	50 MB	1	1	Development and testing
Basic	2 GB	3	1	Small production workloads
Standard S1	25 GB	12	12	Most production scenarios
Standard S2	100 GB	12	12	Larger datasets
Standard S3	200 GB	12	12	High-volume queries
Storage Optimized	1-2 TB	12	12	Large document collections

Pricing is based on search units (replicas × partitions). Free tier includes 10,000 documents and 50 MB storage.

Getting Started

Create Search Service

Provision a search service in the Azure portal or via CLI.

Define Index Schema

Create an index with fields matching your data structure.

Load Data

Use indexers or push API to populate the index.

Query and Test

Use Search Explorer or SDK to test queries.

Integrate

Add search to your application or agent.

Resources

Quickstart

Create your first search index

RAG Tutorial

Build a RAG application

REST API Reference

Complete API documentation

Vector Search Guide

Implement vector search

Get Started

Azure AI Services

​Azure AI Search

Classic Search

Agentic Retrieval

AI Enrichment

Enterprise Ready

​What is Azure AI Search?

​Key Capabilities

​Why Use Azure AI Search?

Ground AI Responses

Multi-Source Access

Intelligent Processing

Hybrid Search

Multimodal Search

Enterprise Security

​Classic Search

​How It Works

​Query Types

​Agentic Retrieval

​Knowledge Bases

​Query Flow

​Agent Integration

​AI Enrichment

​Built-in Skills

Text Skills

Vision Skills

AI Skills

Utility Skills

​Skillset Example

​Integrated Vectorization

​Security Features

​Document-Level Security

​Network Security

​Monitoring and Optimization

​Search Analytics

​Performance Tuning

​Pricing Tiers

​Getting Started

​Resources

Quickstart

RAG Tutorial

REST API Reference

Vector Search Guide

Azure AI Search

What is Azure AI Search?

Key Capabilities

Why Use Azure AI Search?

Classic Search

How It Works

Query Types

Agentic Retrieval

Knowledge Bases

Query Flow

Agent Integration

AI Enrichment

Built-in Skills

Skillset Example

Integrated Vectorization

Security Features

Document-Level Security

Network Security

Monitoring and Optimization

Search Analytics

Performance Tuning

Pricing Tiers

Getting Started

Resources