Azure.AI.DocumentIntelligence (.NET)

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

Installation

dotnet add package Azure.AI.DocumentIntelligence dotnet add package Azure.Identity

Current Version: v1.0.0 (GA)

Environment Variables

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