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)

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

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

Client	Purpose
`DocumentIntelligenceClient`	Analyze documents, classify documents
`DocumentIntelligenceAdministrationClient`	Build/manage custom models and classifiers

Prebuilt Models

Model ID	Description
`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

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)

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

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

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

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

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

// 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

Type	Description
`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

Mode	Use Case
`DocumentBuildMode.Template`	Fixed layout documents (forms)
`DocumentBuildMode.Neural`	Variable layout documents

Best Practices

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

Error Handling

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

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

Reference Links

Resource	URL
NuGet Package	https://www.nuget.org/packages/Azure.AI.DocumentIntelligence
API Reference	https://learn.microsoft.com/dotnet/api/azure.ai.documentintelligence
GitHub Samples	https://github.com/Azure/azure-sdk-for-net/tree/main/sdk/documentintelligence/Azure.AI.DocumentIntelligence/samples
Document Intelligence Studio	https://documentintelligence.ai.azure.com/
Prebuilt Models	https://aka.ms/azsdk/formrecognizer/models

When to Use

This skill is applicable to execute the workflow or actions described in the overview.

Limitations

Use this skill only when the task clearly matches the scope described above.
Do not treat the output as a substitute for environment-specific validation, testing, or expert review.
Stop and ask for clarification if required inputs, permissions, safety boundaries, or success criteria are missing.

azure-ai-document-intelligence-dotnet

Azure.AI.DocumentIntelligence (.NET)

Installation

Environment Variables