Custom Instrumentation

To instrument certain regions of your code, you can create transactions to capture them.

// Transaction can be started by providing, at minimum, the name and the operation
var transaction = SentrySdk.StartTransaction(

// Transactions can have child spans (and those spans can have child spans as well)
var span = transaction.StartChild("test-child-operation");

// ...
// (Perform the operation represented by the span/transaction)
// ...

span.Finish(); // Mark the span as finished
transaction.Finish(); // Mark the transaction as finished and send it to Sentry

For example, if you want to create a transaction for a user interaction in your application:

// Let's say this method is invoked when a user clicks on the checkout button of your shop
public async Task PerformCheckoutAsync()
  // This will create a new Transaction for you
  var transaction = SentrySdk.StartTransaction(
      "checkout", // name
      "perform-checkout" // operation

  // Set transaction on scope to associate with errors and get included span instrumentation
  // If there's currently an unfinished transaction, it may be dropped
  SentrySdk.ConfigureScope(scope => scope.Transaction = transaction);

  // Validate the cart
  var validationSpan = transaction.StartChild(
      "validation", // operation
      "validating shopping cart" // description

  await ValidateShoppingCartAsync();


  // Process the order
  var processSpan = transaction.StartChild(
      "process", // operation
      "processing shopping cart" // description

  await ProcessShoppingCartAsync();



This example will send a transaction checkout to Sentry. The transaction will contain a validation span that measures how long ValidateShoppingCartAsync took and a process span that measures ProcessShoppingCartAsync. Finally, the call to transaction.Finish() will finish the transaction and send it to Sentry.

Retrieve a Transaction

In cases where you want to attach Spans to an already ongoing Transaction you can use SentrySdk.GetSpan(). If there is a running Transaction or Span currently on the scope, this method will return a SentryTransaction or Span; otherwise, it returns null.

using Sentry;

var span = SentrySdk.GetSpan();

if (span == null)
    span = SentrySdk.StartTransaction("task", "op");
    span = span.StartChild("subtask");
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