pixels

Pixels

Pixels are one-off telemetry events sent via HTTP GET with a name and optional parameters. They are used for:

• Basic feature usage events (e.g., button clicks, screen impressions)
• Errors (e.g., network failures, parsing errors)
• Conversion and retention (e.g, subscription purchase and activation)

Pixels have the following requirements:

• Use clear & transparent naming, so it's obvious what the pixel and parameters are for. Pixel names should be self-documenting - avoid cryptic abbreviations or shorthand.
• Only include information that is essential for the pixel
• Do not use values that are overly precise, e.g. if using an integer value in a parameter, bucket it into ranges rather than including the value verbatim
• Never include PII, URLs, or other forms of user-identifiable information in pixel names or parameters

For new production iOS code, use PixelKit instead of the legacy iOS Pixel, DailyPixel, UniquePixel, TimedPixel, or PersistentPixel APIs. Danger exempts only the legacy infrastructure files named by its check, plus test and mock files; these exemptions do not apply to other production code.

Types of Pixels

Standard Pixels

Sent every time the event occurs.

pixelKit.fire(event)

pixelKit.fire(event, options: .parameters(["source": "manual"]))

Daily Pixels

Sent once per day per event. PixelKit appends _daily to the event name. Used to determine the number of users affected by a particular error.

pixelKit.fire(event, frequency: .daily)

Unique Pixels

Sent once per install for the lifetime of the install. The event name must end with _u.

pixelKit.fire(uniqueEvent, frequency: .uniqueByName)

Pixel Definition Patterns

Legacy iOS Pixels

Existing legacy iOS pixels are defined as cases on Pixel.Event in iOS/Core/PixelEvent.swift. Each enum case maps to an HTTP pixel name string via a computed name property. This section is reference material for that existing system only.