Android RUM SDK Data Collection

Overview

Flashcat Android RUM SDK collects multiple metrics and attributes by default for all RUM events. You can also add custom attributes to extend the default data set.

Application Startup

Flashcat collects the following metrics from app startup:

Metric	Description
cold_start_duration	Cold start duration: time from app process creation to first Activity rendering completion.
warm_start_duration	Warm start duration: app process already exists, time from Activity start to rendering completion.
hot_start_duration	Hot start duration: both app and Activity are in memory, time from Activity resume to rendering completion.
activity_start_duration	Activity start duration: time from `onCreate` to first frame rendering completion.
is_pre_warmed	Boolean indicating whether the app was started through pre-warming (Android 11+).

Startup type descriptions:

Cold start: First launch of the app or launch after process termination. Requires loading all resources and initializing app state.

Warm start: App process is in memory, but Activity needs to be recreated.

Hot start: Both app and Activity are in memory, only need to bring Activity to foreground.

View Monitoring and App Lifecycle

A View represents a unique screen that users see in the app. Each View start creates a new RUM event, which is updated throughout the View's lifecycle. Views collect information about all resources, actions, errors, and long tasks that occur during their lifecycle.

In Android, Activities and Fragments are considered Views. By default, the SDK uses the following strategies to automatically track Views:

ActivityViewTrackingStrategy: Tracks each Activity as a View based on Activity lifecycle.

FragmentViewTrackingStrategy: Tracks each Fragment as a View based on Fragment lifecycle.

MixedViewTrackingStrategy: Tracks both Activities and Fragments simultaneously.

NavigationViewTrackingStrategy: Tracking strategy for Jetpack Navigation component.

You can also manually call RumMonitor.startView() and RumMonitor.stopView() to customize View tracking.

Default Attributes

Flashcat RUM SDK attaches the following default attributes to all events. These attributes help you understand user device, network status, and app context.

Common Core Attributes

Attribute Name	Type	Description
`application.id`	string	Flashcat application ID.
`application.name`	string	App package name (e.g., `com.example.app`).
`application.version`	string	App version name.
`application.build`	string	App build version number.
`session.id`	string	Unique session ID used to group events in a user journey.
`session.type`	string	Session type: `user`.
`view.id`	string	Unique ID generated for each View.
`view.url`	string	Normalized URL of the View (Activity or Fragment class name).
`view.name`	string	Customizable View name.
`env`	string	App environment name (e.g., `prod`, `dev`).
`service`	string	Service name used to distinguish different modules or microservices.
`version`	string	App version.
`sdk_version`	string	Flashcat SDK version.
`date`	number	Event timestamp (epoch milliseconds).
`type`	string	Event type (e.g., `view`, `resource`, `action`, `error`, `long_task`).

Device Attributes

The following device-related attributes are automatically collected for all RUM events:

Attribute Name	Type	Description
`device.type`	string	Device type, such as `mobile`, `tablet`, `tv`, etc.
`device.name`	string	Device commercial name (e.g., `Samsung Galaxy S21`).
`device.model`	string	Device model (e.g., `SM-G991B`).
`device.brand`	string	Device brand (e.g., `Samsung`).
`device.architecture`	string	Device architecture (e.g., `arm64-v8a`).
`device.marketing_name`	string	Marketing name of the device.

Connectivity Attributes

The following network-related attributes are automatically collected for all RUM events:

Attribute Name	Type	Description
`connectivity.status`	string	Device network reachability status (`connected`, `not_connected`, `maybe`).
`connectivity.interfaces`	array	List of available network interfaces (e.g., `wifi`, `cellular`, `ethernet`).
`connectivity.cellular.technology`	string	Cellular network technology type (e.g., `LTE`, `5G`).
`connectivity.cellular.carrier_name`	string	Carrier name (e.g., `China Mobile`).

Operating System Attributes

The following OS-related attributes are automatically collected for all RUM events:

Attribute Name	Type	Description
`os.name`	string	Operating system name (e.g., `Android`).
`os.version`	string	Operating system version (e.g., `13`).
`os.version_major`	string	OS major version number (e.g., `13`).
`os.build`	string	System build number (e.g., `TQ2A.230505.002`).

Geolocation Attributes

Flashcat RUM can infer geolocation information from the user's IP address:

Attribute Name	Type	Description
`geo.country`	string	Country name.
`geo.country_iso`	string	Country ISO code.
`geo.city`	string	City name.

Note: Geolocation information is inferred by the Flashcat backend from the client IP address and does not collect precise GPS location on the client.

Global User Attributes

You can set user information through the setUser() API, which will be attached to all RUM events:

Attribute Name	Type	Description
`usr.id`	string	Unique user identifier.
`usr.name`	string	User-friendly name.
`usr.email`	string	User email address.

You can also add custom user attributes, such as usr.plan, usr.role, etc.

Event-Specific Attributes

Besides default attributes, different types of RUM events also collect specific metrics and attributes.

Session Attributes

Attribute Name	Type	Description
`session.id`	string	Unique session ID.
`session.type`	string	Session type: `user`.
`session.has_replay`	bool	Whether the session includes session replay recording.
`session.is_active`	bool	Whether the session is active.

View Attributes

View events include the following specific attributes and performance metrics:

Attribute Name	Type	Description
`view.id`	string	Unique ID for each View.
`view.name`	string	Custom name for the View.
`view.url`	string	URL of the View (Activity or Fragment class name).
`view.time_spent`	number(ns)	Time spent by the user on this View.
`view.loading_time`	number(ns)	Time required for View loading to complete.
`view.loading_type`	string	View loading type: `initial_load`, `activity_display`, `fragment_display`.
`view.first_contentful_paint`	number(ns)	First contentful paint time (API 29+ only).
`view.action.count`	number	Count of all actions collected in the View.
`view.resource.count`	number	Count of all resources collected in the View.
`view.error.count`	number	Count of all errors collected in the View.
`view.long_task.count`	number	Count of all long tasks collected in the View.
`view.crash.count`	number	Count of all crashes collected in the View.
`view.is_active`	bool	Whether the View is still active.

Resource Attributes

Resource events represent network requests in the app. Collected attributes include:

Attribute Name	Type	Description
`resource.id`	string	Unique identifier for the resource.
`resource.type`	string	Resource type (e.g., `xhr`, `fetch`, `image`, `css`, `js`, `font`, `media`, `other`).
`resource.url`	string	URL of the resource.
`resource.method`	string	HTTP method (e.g., `GET`, `POST`).
`resource.status_code`	number	HTTP response status code.
`resource.duration`	number(ns)	Total time spent loading the resource.
`resource.size`	number	Resource size (bytes).
`resource.dns.duration`	number(ns)	DNS resolution time (`domainLookupEnd - domainLookupStart`).
`resource.connect.duration`	number(ns)	Time to establish connection (`connectEnd - connectStart`).
`resource.ssl.duration`	number(ns)	TLS handshake time (`connectEnd - secureConnectionStart`), HTTPS only.
`resource.first_byte.duration`	number(ns)	Time waiting for first byte response (`responseStart - requestStart`).
`resource.download.duration`	number(ns)	Time downloading response (`responseEnd - responseStart`).
`resource.redirect.duration`	number(ns)	Time spent on subsequent HTTP redirects (`redirectEnd - redirectStart`).
`resource.provider.name`	string	Resource provider name, defaults to `unknown`.
`resource.provider.domain`	string	Resource provider domain.
`resource.provider.type`	string	Resource provider type (e.g., `first-party`, `cdn`, `ad`, `analytics`).

Error Attributes

Frontend errors are collected through RUM, and error messages and stack traces (if available) are included:

Attribute Name	Type	Description
`error.source`	string	Error source (e.g., `webview`, `logger`, `network`, `source`, `console`).
`error.type`	string	Error type or error code.
`error.message`	string	Concise, human-readable one-line error message.
`error.stack`	string	Stack trace or supplemental information about the error.
`error.issue_id`	string	Unique identifier for the error issue.
`error.category`	string	High-level categorization of errors. Possible values: `ANR`, `Exception`.
`error.file`	string	File name where the error occurred (for error tracking issues).
`error.line`	number	Line number where the error occurred.
`error.is_crash`	bool	Indicates whether this error caused an app crash.

Network Errors

Network errors include information about failed HTTP requests and collect the following attributes:

Attribute Name	Type	Description
`error.resource.status_code`	number	HTTP response status code.
`error.resource.method`	string	HTTP method (e.g., `POST`, `GET`).
`error.resource.url`	string	Resource URL.
`error.resource.provider.name`	string	Resource provider name, defaults to `unknown`.
`error.resource.provider.domain`	string	Resource provider domain.
`error.resource.provider.type`	string	Resource provider type (e.g., `first-party`, `cdn`, `ad`, `analytics`).

Action Timing Attributes

Actions represent user interactions with the app (e.g., taps, swipes, scrolls).

Attribute Name	Type	Description
`action.loading_time`	number(ns)	Loading time for the action.
`action.long_task.count`	number	Count of all long tasks for this action.
`action.resource.count`	number	Count of all resources for this action.
`action.error.count`	number	Count of all errors for this action.

Action Attributes

Attribute Name	Type	Description
`action.id`	string	UUID for the user action.
`action.type`	string	User action type (e.g., `tap`, `scroll`, `swipe`, `application_start`).
`action.name`	string	Name of the user action.
`action.target.name`	string	Element the user interacted with, only for automatically collected actions.

Data Storage

Before data is uploaded to Flashcat, it is stored in plain text in the app's cache directory. This cache folder is protected by Android app sandboxing, meaning that on most devices, other apps cannot read this data. However, if the mobile device is rooted or someone tampers with the Linux kernel, stored data may become readable.

Storage location: /data/data/<package_name>/cache/com.flashcat.rum/

Note: Sensitive data should not be included in RUM events, or should be obfuscated or filtered before sending through the beforeSend callback.

Data Upload

Flashcat RUM Android SDK considers user bandwidth impact while ensuring data transmission. The SDK uploads events in batches as follows:

Batching Mechanism

When collecting events:
Flashcat SDK appends uncompressed events to batch files (using TLV encoding format, Tag-Length-Value).

When uploading (when a batch is considered "closed"):

Read batch file and extract events

Deduplicate RUM events (remove redundant View events; other traces are not optimized)

Build trace-specific payloads

Compress payloads and send

Upload Trigger Conditions

Batches are uploaded under the following conditions:

Batch file size reaches threshold (e.g., 4MB)

Number of events in batch reaches threshold

App switches to background

Periodic upload (e.g., every 5 seconds)

Upload Strategy

When network is available: Prioritize upload via WiFi, mobile network also supported.

When battery is sufficient: Ensure not to excessively consume device battery.

Retry on failure: If upload fails, batches are retained locally until successfully sent.

Data Compression

Before upload, Flashcat SDK performs gzip compression on batch data to reduce network traffic and upload time.

Direct Boot Mode Support

If your app supports Direct Boot mode (starts before device unlock), note that data captured before device unlock will not be recorded as credential encrypted storage is not yet available.

Flashcat SDK will start collecting data after device unlock. If you need to collect data in Direct Boot mode, ensure device encrypted storage is used instead of credential encrypted storage.

Data Collection

Overview#

Application Startup#

View Monitoring and App Lifecycle#

Default Attributes#

Common Core Attributes#

Device Attributes#

Connectivity Attributes#

Operating System Attributes#

Geolocation Attributes#

Global User Attributes#

Event-Specific Attributes#

Session Attributes#

View Attributes#

Resource Attributes#

Error Attributes#

Network Errors#

Action Timing Attributes#

Action Attributes#

Data Storage#

Data Upload#

Batching Mechanism#

Upload Trigger Conditions#

Upload Strategy#

Data Compression#

Direct Boot Mode Support#

Further Reading#