Set Up

With performance monitoring, Sentry tracks your software performance, measuring metrics like throughput and latency, and displaying the impact of errors across multiple systems. Sentry captures distributed traces consisting of transactions and spans, which measure individual services and individual operations within those services. Learn more about our model in Distributed Tracing.

Configure the Sample Rate

Once you configure the sample rate, tracing will be enabled in your app. Set the sample rate for your transactions by either:

  1. Setting a uniform sample rate for all transactions using the traces-sample-rate option in your SDK config to a number between 0 and 1. (For example, to send 20% of transactions, set traces-sample-rate to 0.2.)
  2. Controlling the sample rate based on the transaction itself and the context in which it's captured, by providing a function to the traces-sampler config option.

The two options are meant to be mutually exclusive. If you set both, traces-sampler will take precedence.

Copied
import Sentry

SentrySDK.start { options in
    options.dsn = "https://examplePublicKey@o0.ingest.sentry.io/0"

    // Example uniform sample rate: capture 100% of transactions
    // In Production you will probably want a smaller number such as 0.5 for 50%
    options.tracesSampleRate = 1.0

    // OR if you prefer, determine traces sample rate based on the
    // sampling context
    options.tracesSampler = { context in
         // Don't miss any transactions for VIP users 
        if context?["vip"] as? Bool == true { 
            return 1.0 
        } else { 
            return 0.25 // 25% for everything else
        }
    }
}

Learn more about how the options work in Sampling Transactions.

Verify

Verify that performance monitoring is working correctly by setting traces-sample-rate to 1.0 as that ensures that every transaction will be sent to Sentry.

Once testing is complete, we recommend lowering this value in production by either lowering your traces-sample-rate value, or switching to using traces-sampler to dynamically sample and filter your transactions.

Connecting Services

If you are also using Performance Monitoring for JavaScript depending on where your request originates there are two methods to connect your traces:

  1. For requests that start in your backend, this is done by adding a meta tag in your HTML template that contains tracing information.
  2. For requests that start in JavaScript, this is done by the SDK setting a header on requests to your backend.

Otherwise backend services with Performance Monitoring will connect automatically.

Next Steps:

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