azure-ai-document-intelligence-dotnet

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Azure AI Document Intelligence SDK for .NET. Extract text, tables, and structured data from documents using prebuilt and custom models. Use for invoice processing, receipt extraction, ID document analysis, and custom document models. Triggers: "Document Intelligence", "DocumentIntelligenceClient", "form recognizer", "invoice extraction", "receipt OCR", "document analysis .NET".

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npx skill4agent add microsoft/agent-skills azure-ai-document-intelligence-dotnet

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azure-ai-document-intelligencedotnet-sdkdocument-extractioninvoice-processingcustom-model-management

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Azure.AI.DocumentIntelligence (.NET)

Extract text, tables, and structured data from documents using prebuilt and custom models.

Installation

bash
dotnet add package Azure.AI.DocumentIntelligence
dotnet add package Azure.Identity
Current Version: v1.0.0 (GA)

Environment Variables

bash
DOCUMENT_INTELLIGENCE_ENDPOINT=https://<resource-name>.cognitiveservices.azure.com/
DOCUMENT_INTELLIGENCE_API_KEY=<your-api-key>
BLOB_CONTAINER_SAS_URL=https://<storage>.blob.core.windows.net/<container>?<sas-token>

Authentication

Microsoft Entra ID (Recommended)

csharp
using Azure.Identity;
using Azure.AI.DocumentIntelligence;

string endpoint = Environment.GetEnvironmentVariable("DOCUMENT_INTELLIGENCE_ENDPOINT");
var credential = new DefaultAzureCredential();
var client = new DocumentIntelligenceClient(new Uri(endpoint), credential);
Note: Entra ID requires a custom subdomain (e.g., 
https://<resource-name>.cognitiveservices.azure.com/
), not a regional endpoint.

API Key

csharp
string endpoint = Environment.GetEnvironmentVariable("DOCUMENT_INTELLIGENCE_ENDPOINT");
string apiKey = Environment.GetEnvironmentVariable("DOCUMENT_INTELLIGENCE_API_KEY");
var client = new DocumentIntelligenceClient(new Uri(endpoint), new AzureKeyCredential(apiKey));

Client Types

ClientPurpose
DocumentIntelligenceClient
Analyze documents, classify documents
DocumentIntelligenceAdministrationClient
Build/manage custom models and classifiers

Prebuilt Models

Model IDDescription
prebuilt-read
Extract text, languages, handwriting
prebuilt-layout
Extract text, tables, selection marks, structure
prebuilt-invoice
Extract invoice fields (vendor, items, totals)
prebuilt-receipt
Extract receipt fields (merchant, items, total)
prebuilt-idDocument
Extract ID document fields (name, DOB, address)
prebuilt-businessCard
Extract business card fields
prebuilt-tax.us.w2
Extract W-2 tax form fields
prebuilt-healthInsuranceCard.us
Extract health insurance card fields

Core Workflows

1. Analyze Invoice

csharp
using Azure.AI.DocumentIntelligence;

Uri invoiceUri = new Uri("https://example.com/invoice.pdf");

Operation<AnalyzeResult> operation = await client.AnalyzeDocumentAsync(
    WaitUntil.Completed, 
    "prebuilt-invoice", 
    invoiceUri);

AnalyzeResult result = operation.Value;

foreach (AnalyzedDocument document in result.Documents)
{
    if (document.Fields.TryGetValue("VendorName", out DocumentField vendorNameField)
        && vendorNameField.FieldType == DocumentFieldType.String)
    {
        string vendorName = vendorNameField.ValueString;
        Console.WriteLine($"Vendor Name: '{vendorName}', confidence: {vendorNameField.Confidence}");
    }

    if (document.Fields.TryGetValue("InvoiceTotal", out DocumentField invoiceTotalField)
        && invoiceTotalField.FieldType == DocumentFieldType.Currency)
    {
        CurrencyValue invoiceTotal = invoiceTotalField.ValueCurrency;
        Console.WriteLine($"Invoice Total: '{invoiceTotal.CurrencySymbol}{invoiceTotal.Amount}'");
    }
    
    // Extract line items
    if (document.Fields.TryGetValue("Items", out DocumentField itemsField)
        && itemsField.FieldType == DocumentFieldType.List)
    {
        foreach (DocumentField item in itemsField.ValueList)
        {
            var itemFields = item.ValueDictionary;
            if (itemFields.TryGetValue("Description", out DocumentField descField))
                Console.WriteLine($"  Item: {descField.ValueString}");
        }
    }
}

2. Extract Layout (Text, Tables, Structure)

csharp
Uri fileUri = new Uri("https://example.com/document.pdf");

Operation<AnalyzeResult> operation = await client.AnalyzeDocumentAsync(
    WaitUntil.Completed, 
    "prebuilt-layout", 
    fileUri);

AnalyzeResult result = operation.Value;

// Extract text by page
foreach (DocumentPage page in result.Pages)
{
    Console.WriteLine($"Page {page.PageNumber}: {page.Lines.Count} lines, {page.Words.Count} words");
    
    foreach (DocumentLine line in page.Lines)
    {
        Console.WriteLine($"  Line: '{line.Content}'");
    }
}

// Extract tables
foreach (DocumentTable table in result.Tables)
{
    Console.WriteLine($"Table: {table.RowCount} rows x {table.ColumnCount} columns");
    foreach (DocumentTableCell cell in table.Cells)
    {
        Console.WriteLine($"  Cell ({cell.RowIndex}, {cell.ColumnIndex}): {cell.Content}");
    }
}

3. Analyze Receipt

csharp
Operation<AnalyzeResult> operation = await client.AnalyzeDocumentAsync(
    WaitUntil.Completed, 
    "prebuilt-receipt", 
    receiptUri);

AnalyzeResult result = operation.Value;

foreach (AnalyzedDocument document in result.Documents)
{
    if (document.Fields.TryGetValue("MerchantName", out DocumentField merchantField))
        Console.WriteLine($"Merchant: {merchantField.ValueString}");
        
    if (document.Fields.TryGetValue("Total", out DocumentField totalField))
        Console.WriteLine($"Total: {totalField.ValueCurrency.Amount}");
        
    if (document.Fields.TryGetValue("TransactionDate", out DocumentField dateField))
        Console.WriteLine($"Date: {dateField.ValueDate}");
}

4. Build Custom Model

csharp
var adminClient = new DocumentIntelligenceAdministrationClient(
    new Uri(endpoint), 
    new AzureKeyCredential(apiKey));

string modelId = "my-custom-model";
Uri blobContainerUri = new Uri("<blob-container-sas-url>");

var blobSource = new BlobContentSource(blobContainerUri);
var options = new BuildDocumentModelOptions(modelId, DocumentBuildMode.Template, blobSource);

Operation<DocumentModelDetails> operation = await adminClient.BuildDocumentModelAsync(
    WaitUntil.Completed, 
    options);

DocumentModelDetails model = operation.Value;

Console.WriteLine($"Model ID: {model.ModelId}");
Console.WriteLine($"Created: {model.CreatedOn}");

foreach (var docType in model.DocumentTypes)
{
    Console.WriteLine($"Document type: {docType.Key}");
    foreach (var field in docType.Value.FieldSchema)
    {
        Console.WriteLine($"  Field: {field.Key}, Confidence: {docType.Value.FieldConfidence[field.Key]}");
    }
}

5. Build Document Classifier

csharp
string classifierId = "my-classifier";
Uri blobContainerUri = new Uri("<blob-container-sas-url>");

var sourceA = new BlobContentSource(blobContainerUri) { Prefix = "TypeA/train" };
var sourceB = new BlobContentSource(blobContainerUri) { Prefix = "TypeB/train" };

var docTypes = new Dictionary<string, ClassifierDocumentTypeDetails>()
{
    { "TypeA", new ClassifierDocumentTypeDetails(sourceA) },
    { "TypeB", new ClassifierDocumentTypeDetails(sourceB) }
};

var options = new BuildClassifierOptions(classifierId, docTypes);

Operation<DocumentClassifierDetails> operation = await adminClient.BuildClassifierAsync(
    WaitUntil.Completed, 
    options);

DocumentClassifierDetails classifier = operation.Value;
Console.WriteLine($"Classifier ID: {classifier.ClassifierId}");

6. Classify Document

csharp
string classifierId = "my-classifier";
Uri documentUri = new Uri("https://example.com/document.pdf");

var options = new ClassifyDocumentOptions(classifierId, documentUri);

Operation<AnalyzeResult> operation = await client.ClassifyDocumentAsync(
    WaitUntil.Completed, 
    options);

AnalyzeResult result = operation.Value;

foreach (AnalyzedDocument document in result.Documents)
{
    Console.WriteLine($"Document type: {document.DocumentType}, confidence: {document.Confidence}");
}

7. Manage Models

csharp
// Get resource details
DocumentIntelligenceResourceDetails resourceDetails = await adminClient.GetResourceDetailsAsync();
Console.WriteLine($"Custom models: {resourceDetails.CustomDocumentModels.Count}/{resourceDetails.CustomDocumentModels.Limit}");

// Get specific model
DocumentModelDetails model = await adminClient.GetModelAsync("my-model-id");
Console.WriteLine($"Model: {model.ModelId}, Created: {model.CreatedOn}");

// List models
await foreach (DocumentModelDetails modelItem in adminClient.GetModelsAsync())
{
    Console.WriteLine($"Model: {modelItem.ModelId}");
}

// Delete model
await adminClient.DeleteModelAsync("my-model-id");

Key Types Reference

TypeDescription
DocumentIntelligenceClient
Main client for analysis
DocumentIntelligenceAdministrationClient
Model management
AnalyzeResult
Result of document analysis
AnalyzedDocument
Single document within result
DocumentField
Extracted field with value and confidence
DocumentFieldType
String, Date, Number, Currency, etc.
DocumentPage
Page info (lines, words, selection marks)
DocumentTable
Extracted table with cells
DocumentModelDetails
Custom model metadata
BlobContentSource
Training data source

Build Modes

ModeUse Case
DocumentBuildMode.Template
Fixed layout documents (forms)
DocumentBuildMode.Neural
Variable layout documents

Best Practices

  1. Use DefaultAzureCredential for production
  2. Reuse client instances — clients are thread-safe
  3. Handle long-running operations — Use 
    WaitUntil.Completed
    for simplicity
  4. Check field confidence — Always verify 
    Confidence
    property
  5. Use appropriate model — Prebuilt for common docs, custom for specialized
  6. Use custom subdomain — Required for Entra ID authentication

Error Handling

csharp
using Azure;

try
{
    var operation = await client.AnalyzeDocumentAsync(
        WaitUntil.Completed, 
        "prebuilt-invoice", 
        documentUri);
}
catch (RequestFailedException ex)
{
    Console.WriteLine($"Error: {ex.Status} - {ex.Message}");
}

Related SDKs

SDKPurposeInstall
Azure.AI.DocumentIntelligence
Document analysis (this SDK)
dotnet add package Azure.AI.DocumentIntelligence
Azure.AI.FormRecognizer
Legacy SDK (deprecated)Use DocumentIntelligence instead

Reference Links

ResourceURL
NuGet Packagehttps://www.nuget.org/packages/Azure.AI.DocumentIntelligence
API Referencehttps://learn.microsoft.com/dotnet/api/azure.ai.documentintelligence
GitHub Sampleshttps://github.com/Azure/azure-sdk-for-net/tree/main/sdk/documentintelligence/Azure.AI.DocumentIntelligence/samples
Document Intelligence Studiohttps://documentintelligence.ai.azure.com/
Prebuilt Modelshttps://aka.ms/azsdk/formrecognizer/models