> ## Documentation Index
> Fetch the complete documentation index at: https://docs.appsignal.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Sinatra

[Sinatra](http://www.sinatrarb.com/) applications are officially supported. Instrumenting Sinatra applications requires some manual setup. Follow the installation steps in AppSignal, starting by clicking 'Add app' on the [accounts screen](https://appsignal.com/accounts).

<Note>
  Is your application using a combination of Rails, Grape, Hanami, Padrino or Sinatra? Follow our guide for [instrumenting multiple Rack applications](/ruby/integrations/rack-libraries).
</Note>

## Installation

After installing the AppSignal gem, add the AppSignal integration after requiring `sinatra` (or `sinatra/base`).

<CodeGroup>
  ```ruby Ruby theme={null}
  require "appsignal" # Add this require
  require "sinatra" # or require "sinatra/base"

  # Load the Sinatra integration
  Appsignal.load(:sinatra)
  # Start AppSignal
  Appsignal.start

  # For Ruby gem 3.11 and older
  require "appsignal/integrations/sinatra"
  ```
</CodeGroup>

Then, create the AppSignal configuration file. For more details on configuring AppSignal, see the [Ruby configuration](/ruby/configuration) page.

After these steps, start your Sinatra app and wait for data to arrive in AppSignal.

## Ignoring errors

To ignore a specific Sinatra error, set the `Sinatra.skip_appsignal_error` flag in the request environment. This flag will tell AppSignal to ignore the error that occurs during the request and not report it to AppSignal.

Only ignore errors like this if you need to ignore errors from a Sinatra app using code. See the [`ignore_errors` option](/guides/filter-data/ignore-errors) to ignore it for the entire app. To avoid being notified about an error, see [our notification settings](/application/notification-settings).

<CodeGroup>
  ```ruby Ruby theme={null}
  get "/" do
    env["sinatra.skip_appsignal_error"] = true # Add this line to an endpoint or callback
    raise "uh oh" # Example error, don't copy this
  end
  ```
</CodeGroup>