Decode US Driver License PDF417 Barcodes with C# / .NET

Why US Driver License PDF417 Decoding Needs a Dedicated Pipeline

The barcode on the back of a US driver license is not ordinary printed text. PDF417 uses stacked rows, error correction, and a structured AAMVA payload. Glare, blur, perspective, small barcodes, and partial cropping can prevent a reliable decode. General OCR and generative vision models may produce plausible-looking identity fields, but they cannot prove those values came from a valid barcode payload.

A Deterministic PDF417 API for C# / .NET

Send a JPG, PNG, or WebP image to the US driver license PDF417 API. StructOCR locates and decodes the barcode, validates the result, parses AAMVA elements, and returns normalized JSON. Try the workflow first in the free PDF417 scanner.

Production Use Cases

• US Customer Onboarding: Pre-fill identity and address fields from an AAMVA-compliant license-back barcode.
• Rental and Fleet Intake: Capture license number, class, restrictions, endorsements, and expiration date.
• Quality-Control Queues: Route 422 responses to a retake flow instead of accepting guessed identity data.

Implementation: C# / .NET REST Request

Read the license-back image, Base64 encode it, send it with the x-api-key header, and treat HTTP 422 as a request for a clearer image.

Prerequisite: .NET 8+ with `System.Net.Http.Json`

using System.Net.Http.Json;
using System.Text.Json;

using var http = new HttpClient { Timeout = TimeSpan.FromSeconds(30) };
http.DefaultRequestHeaders.Add("x-api-key", Environment.GetEnvironmentVariable("STRUCTOCR_API_KEY"));

var image = await File.ReadAllBytesAsync("license-back.jpg");
var payload = new { img = Convert.ToBase64String(image) };
using var response = await http.PostAsJsonAsync("https://api.structocr.com/v1/driver-license-pdf417", payload);
var body = await response.Content.ReadAsStringAsync();

using var result = JsonDocument.Parse(body);
if ((int)response.StatusCode == 422)
{
    Console.WriteLine("Retake image: " + result.RootElement.GetProperty("error").GetString());
}
else
{
    response.EnsureSuccessStatusCode();
    var data = result.RootElement.GetProperty("data");
    Console.WriteLine("License: " + data.GetProperty("document_number").GetString());
    Console.WriteLine("DOB: " + data.GetProperty("date_of_birth").GetString());
    Console.WriteLine("AAMVA: " + data.GetProperty("aamva_version").GetInt32());
}

Sample AAMVA JSON Output

The example uses fictional values. Optional AAMVA elements return null when absent.

{
  "success": true,
  "data": {
    "type": "drivers_license",
    "source": "pdf417",
    "country_code": "USA",
    "region": "CA",
    "document_number": "SAMPLE1234",
    "surname": "SAMPLE",
    "given_names": "ALEX MORGAN",
    "first_name": "ALEX",
    "middle_name": "MORGAN",
    "sex": "F",
    "date_of_birth": "1990-01-15",
    "date_of_issue": "2025-01-15",
    "date_of_expiry": "2030-01-15",
    "address": "100 EXAMPLE AVE",
    "city": "SAMPLE CITY",
    "postal_code": "90001",
    "vehicle_class": "C",
    "restrictions": "NONE",
    "endorsements": "NONE",
    "document_discriminator": "SAMPLE-DISCRIMINATOR",
    "issuer_identification_number": "636000",
    "aamva_version": 10,
    "jurisdiction_version": 0
  }
}