Web RUM Data Collection

Overview

Flashcat Web RUM SDK generates events with associated metrics and attributes. Each RUM event includes default attributes, such as the page URL corresponding to the event (view.url) and user information like device type (device.type) and country (geo.country).

Additionally, different event types have specific additional metrics and attributes. For example, the view.loading_time metric is associated with view events, while the resource.method attribute is associated with resource events.

Default Attributes

Flashcat Web RUM SDK automatically captures the following default attributes, which apply to all RUM event types.

Common Core Attributes

Attribute	Type	Description
`date`	Integer	Event timestamp (in milliseconds, epoch milliseconds).
`type`	String	Event type (such as `session`, `view`, `resource`, `error`, `action`).
`application.id`	String	Unique application identifier.
`service`	String	Service name that generated this event.
`env`	String	Application environment name (such as `prod`, `dev`, `staging`).
`version`	String	Application version.
`sdk_version`	String	Flashcat RUM SDK version.

Device

The following device-related attributes are automatically attached to all events collected by Flashcat:

Attribute	Type	Description
`device.type`	String	Device type (such as `Desktop`, `Mobile`, `Tablet`, `TV`, `Other`).
`device.brand`	String	Device brand (such as `Apple`, `Samsung`, `Huawei`).
`device.model`	String	Device model (such as `iPhone`, `iPad`).
`device.name`	String	Device commercial name.

Operating System

The following OS-related attributes are automatically attached to all events collected by Flashcat:

Attribute	Type	Description
`os.name`	String	Operating system name (such as `Mac OS`, `Windows`, `iOS`).
`os.version`	String	OS version number (such as `10.15.7`, `11.0`).
`os.version_major`	String	OS major version number (such as `10`, `11`).

Browser

The following browser-related attributes are automatically attached to all Web RUM events:

Attribute	Type	Description
`browser.name`	String	Browser name (such as `Chrome`, `Firefox`, `Safari`, `Edge`).
`browser.version`	String	Browser version number (such as `91.0.4472.124`).
`browser.version_major`	String	Browser major version number (such as `91`).
`browser.user_agent`	String	User Agent string.
`browser.viewport.width`	Number	Browser viewport width (pixels).
`browser.viewport.height`	Number	Browser viewport height (pixels).

Geolocation

The following attributes relate to the geographic location of the IP address:

Attribute	Type	Description
`geo.country`	String	Country name.
`geo.country_iso_code`	String	Country ISO code (such as `US`, `CN`).
`geo.country_subdivision`	String	First-level administrative division of the country (such as US states, Chinese provinces).
`geo.continent_code`	String	Continent ISO code (such as `EU`, `AS`, `NA`).
`geo.continent`	String	Continent name.
`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 enable user tracking on all RUM events to correlate user sessions and simplify troubleshooting. User attributes are optional, but it's recommended to provide the following:

Attribute	Type	Description
`usr.id`	String	Unique user identifier.
`usr.name`	String	User-friendly name, displayed by default in RUM UI.
`usr.email`	String	User email address. Email is displayed if no username is provided.

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

To set user information, see Tracking User Information.

Event-Specific Attributes

Different event types have specific attributes and metrics.

Session Attributes

Attribute	Type	Description
`session.id`	String	Unique session identifier.
`session.type`	String	Session type (such as `user`, `synthetic`).
`session.is_active`	Boolean	Whether the session is active.
`session.initial_view.id`	String	ID of the initial view in the session.
`session.initial_view.url`	String	URL of the initial view in the session.
`session.initial_view.name`	String	Name of the initial view in the session.
`session.last_view.id`	String	ID of the last view in the session.
`session.last_view.url`	String	URL of the last view in the session.
`session.last_view.name`	String	Name of the last view in the session.
`session.has_replay`	Boolean	Whether session replay is enabled for the session.

View Time Metrics

Flashcat RUM collects all performance metrics from the Navigation Timing API, as well as metrics related to Core Web Vitals.

Attribute	Type	Description
`view.time_spent`	Number (nanoseconds)	Time user spent on this view.
`view.loading_time`	Number (nanoseconds)	Time required for page to fully load (triggered at `loadEventEnd`).
`view.largest_contentful_paint`	Number (nanoseconds)	Largest Contentful Paint (LCP), rendering time of largest visible content element in viewport.
`view.first_input_delay`	Number (nanoseconds)	First Input Delay (FID), time from user's first interaction with page to browser's actual response.
`view.cumulative_layout_shift`	Number	Cumulative Layout Shift (CLS), quantifies unexpected movement of visible elements within viewport.
`view.interaction_to_next_paint`	Number (nanoseconds)	Interaction to Next Paint (INP), measures latency of all user interactions with page.
`view.first_contentful_paint`	Number (nanoseconds)	First Contentful Paint (FCP), time when browser first renders any text, image, non-blank canvas, or SVG.
`view.dom_interactive`	Number (nanoseconds)	Moment parser completes work on main document (`domInteractive`).
`view.dom_content_loaded`	Number (nanoseconds)	Time when initial HTML document is fully loaded and parsed, without waiting for stylesheets, images, and subframes to finish loading (`domContentLoadedEventEnd`).
`view.dom_complete`	Number (nanoseconds)	Time when page and all subresources are ready (`domComplete`).
`view.load_event`	Number (nanoseconds)	Time when load event is triggered (`loadEventEnd`), indicating page is fully loaded.
`view.first_byte`	Number (nanoseconds)	Time to First Byte (TTFB), time from user initiating page load to browser receiving first byte of HTML document (`responseStart`).
`view.redirect.duration`	Number (nanoseconds)	Time spent on redirects (`redirectEnd - redirectStart`).
`view.dns.duration`	Number (nanoseconds)	Time spent on DNS lookup (`domainLookupEnd - domainLookupStart`).
`view.connect.duration`	Number (nanoseconds)	Time spent establishing server connection (`connectEnd - connectStart`).
`view.ssl.duration`	Number (nanoseconds)	Time spent on TLS handshake (`connectEnd - secureConnectionStart`).
`view.request.duration`	Number (nanoseconds)	Time spent requesting HTML document (`responseStart - requestStart`).
`view.response.duration`	Number (nanoseconds)	Time spent downloading HTML document (`responseEnd - responseStart`).
`view.in_foreground_periods.count`	Number	Number of times view was in foreground.
`view.in_foreground_periods.duration`	Number (nanoseconds)	Total time view was in foreground.

View Attributes

Attribute	Type	Description
`view.id`	String	Unique view identifier.
`view.url`	String	URL of the view.
`view.name`	String	Customizable view name.
`view.referrer`	String	Previous page URL (referrer).
`view.action.count`	Number	Number of user actions collected in this view.
`view.error.count`	Number	Number of errors collected in this view.
`view.resource.count`	Number	Number of resources collected in this view.
`view.long_task.count`	Number	Number of long tasks collected in this view.
`view.is_active`	Boolean	Whether the view is active.

Resource Time Metrics

Flashcat RUM collects detailed network timing information from the Resource Timing API for individual resource loading.

Attribute	Type	Description
`resource.duration`	Number (nanoseconds)	Total time required to load the resource.
`resource.size`	Number (bytes)	Resource size.
`resource.connect.duration`	Number (nanoseconds)	Time required to establish server connection (`connectEnd - connectStart`).
`resource.ssl.duration`	Number (nanoseconds)	Time required for TLS handshake. This metric doesn't appear if last request wasn't via HTTPS.
`resource.dns.duration`	Number (nanoseconds)	Time required for DNS resolution (`domainLookupEnd - domainLookupStart`).
`resource.redirect.duration`	Number (nanoseconds)	Time required for subsequent HTTP requests (`redirectEnd - redirectStart`).
`resource.first_byte.duration`	Number (nanoseconds)	Time waiting to receive first response byte (`responseStart - requestStart`).
`resource.download.duration`	Number (nanoseconds)	Time downloading response (`responseEnd - responseStart`).
`resource.render_blocking_status`	String	Resource render blocking status (`blocking`, `non-blocking`).
`resource.first_party`	Boolean	Whether it's a first-party resource (same domain as app).

Resource Attributes

Attribute	Type	Description
`resource.id`	String	Unique resource identifier.
`resource.type`	String	Resource type (such as `xhr`, `fetch`, `css`, `js`, `image`, `font`, `media`).
`resource.method`	String	HTTP method (such as `GET`, `POST`, `PUT`, `DELETE`).
`resource.status_code`	Number	HTTP response status code.
`resource.url`	String	Resource URL.
`resource.url_host`	String	Host portion of the URL.
`resource.url_path`	String	Path portion of the URL.
`resource.url_query`	Object	URL query parameters, parsed as key-value pairs.
`resource.url_scheme`	String	URL protocol (such as `https`, `http`).
`resource.provider.name`	String	Resource provider name, defaults to `unknown`.
`resource.provider.domain`	String	Resource provider domain.
`resource.provider.type`	String	Resource provider type (such as `first-party`, `cdn`, `ad`, `analytics`, `social`).

GraphQL Attributes

If GraphQL request tracking is enabled, the following attributes are attached to resource events:

Attribute	Type	Description
`resource.graphql.operation_type`	String	GraphQL operation type (`query`, `mutation`, `subscription`).
`resource.graphql.operation_name`	String	GraphQL operation name (if provided in request).
`resource.graphql.variables`	String	GraphQL variables sent with request.
`resource.graphql.payload`	String	GraphQL query (limited to 32 KB, only available when `trackPayload` is enabled).
`resource.graphql.errors_count`	Number	Number of errors returned in GraphQL response (only available when `trackResponseErrors` is enabled).
`resource.graphql.errors`	Array	GraphQL errors array, including message, code, locations, and path (only available when `trackResponseErrors` is enabled).

Long Task Time Attributes

Long tasks are tasks that block the main thread for 50 milliseconds or longer. These tasks cause high input latency, slow interactions, or stuttering animations/scrolling.

Attribute	Type	Description
`long_task.duration`	Number (nanoseconds)	Duration of the long task.
`long_task.is_frozen_frame`	Boolean	Whether it's a frozen frame (duration exceeds 700ms).

Error Attributes

Frontend errors are collected through RUM. Error messages and stack traces (if available) are included.

Attribute	Type	Description
`error.id`	String	Unique error identifier.
`error.source`	String	Error source (such as `console`, `network`, `source`, `logger`, `agent`, `webview`, `custom`, `report`).
`error.type`	String	Error type (error code in some cases).
`error.message`	String	Concise, readable single-line error message.
`error.stack`	String	Error stack trace or supplemental information.
`error.issue_id`	String	Unique error issue identifier (same errors are aggregated to the same issue).
`error.fingerprint`	String	Fingerprint used to uniquely identify the error.
`error.handling`	String	Error handling method (`handled`, `unhandled`).
`error.handling_stack`	String	Stack trace when error was handled.
`error.causes`	Array	Information about other errors that caused this error.

Source Errors

Source errors contain code-level information about the error. For more information on different error types, see the MDN documentation.

Attribute	Type	Description
`error.type`	String	Error type (error code in some cases).

Network Errors

Network errors contain information about failed HTTP requests. The following additional attributes are collected:

Attribute	Type	Description
`error.resource.status_code`	Number	HTTP response status code.
`error.resource.method`	String	HTTP method (such as `GET`, `POST`).
`error.resource.url`	String	Resource URL.
`error.resource.url_host`	String	Host portion of the URL.
`error.resource.url_path`	String	Path portion of the URL.
`error.resource.url_scheme`	String	URL protocol.
`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 (such as `first-party`, `cdn`, `ad`, `analytics`).

Action Time Attributes

Attribute	Type	Description
`action.loading_time`	Number (nanoseconds)	Action loading time. Calculation method in Tracking User Actions documentation.
`action.long_task.count`	Number	Number of long tasks triggered by this action.
`action.resource.count`	Number	Number of resources triggered by this action.
`action.error.count`	Number	Number of errors triggered by this action.

Action Attributes

Attribute	Type	Description
`action.id`	String	Unique user action identifier (UUID).
`action.type`	String	User action type (such as `click`, `custom`). For custom user actions, set to `custom`.
`action.target.name`	String	Element user interacted with. Only for automatically collected actions.
`action.name`	String	User-friendly name (such as `Click on #checkout`). For custom user actions, the action name given in API call.

Frustration Signals

Flashcat RUM automatically detects user frustration signals to help you understand issues users encounter in the app.

Attribute	Type	Description
`session.frustration.count`	Number	Total number of frustration signals in the session.
`view.frustration.count`	Number	Total number of frustration signals in the view.
`action.frustration.type:dead_click`	String	Dead click detected by RUM SDK (click with no response).
`action.frustration.type:rage_click`	String	Rage click detected by RUM SDK (consecutive rapid clicks).
`action.frustration.type:error_click`	String	Error click detected by RUM SDK (click triggers error).

UTM Attributes

If URL contains UTM parameters, Flashcat RUM automatically captures the following attributes for tracking marketing campaigns:

Attribute	Type	Description
`view.url_query.utm_source`	String	Parameter in URL tracking traffic source.
`view.url_query.utm_medium`	String	Parameter in URL tracking which channel traffic came from.
`view.url_query.utm_campaign`	String	Parameter in URL identifying specific marketing campaign associated with view.
`view.url_query.utm_content`	String	Parameter in URL identifying specific element user clicked in marketing campaign.
`view.url_query.utm_term`	String	Parameter in URL tracking keywords user searched to trigger given campaign.

Data Storage

Before uploading to Flashcat, data is temporarily stored in plain text in the browser's local storage (LocalStorage or SessionStorage). The SDK follows these rules:

When network is available, data is sent in batches.

If network is unavailable or data upload fails, batches are retained until successfully sent.

Data exceeding a certain time limit is automatically cleaned up to avoid occupying excessive storage space.

This means data won't be lost even if users use your app while offline.

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 Web RUM SDK uploads collected events in batches to the server to optimize network performance and reduce impact on user experience.

Batching Mechanism

Event Collection: SDK adds events to in-memory batch buffer.

Batch Upload: Batches are uploaded when one of the following conditions is met:

Number of events in batch reaches threshold

Batch size reaches threshold

Periodic upload (e.g., every 10 seconds)

Page unload (beforeunload event)

Upload Strategy

Beacon API: Prioritizes using Beacon API to send data, ensuring data isn't lost during page unload.

XHR/Fetch Fallback: If Beacon API is unavailable, uses XMLHttpRequest or Fetch API.

Retry on Failure: If upload fails, batches are retained in local storage until successfully sent.

Data Compression

Before upload, Flashcat SDK compresses batch data to reduce network traffic and upload time.

Privacy and Compliance

Flashcat Web RUM SDK is designed with privacy and data protection in mind:

IP Address Anonymization: SDK can be configured to anonymize IP addresses.

Sensitive Data Filtering: Use beforeSend callback to filter or obfuscate sensitive information.

Cookie and Storage Control: Can configure whether to use cookies and local storage.

GDPR/CCPA Compliance: Supports user privacy opt-out mechanism.

For more information on privacy configuration, see Advanced Configuration.

More Information

Web SDK Integration: Learn how to integrate Flashcat RUM SDK in Web apps

Web SDK Advanced Configuration: Learn how to configure advanced SDK features

RUM Data Collection: Learn about RUM general data collection mechanism

Data Collection

Overview#

Default Attributes#

Common Core Attributes#

Device#

Operating System#

Browser#

Geolocation#

Global User Attributes#

Event-Specific Attributes#

Session Attributes#

View Time Metrics#

View Attributes#

Resource Time Metrics#

Resource Attributes#

GraphQL Attributes#

Long Task Time Attributes#

Error Attributes#

Source Errors#

Network Errors#

Action Time Attributes#

Action Attributes#

Frustration Signals#

UTM Attributes#

Data Storage#

Data Upload#

Batching Mechanism#

Upload Strategy#

Data Compression#

Privacy and Compliance#

More Information#