Data Collection

Web RUM SDK automatically collects rich user behavior and performance data. Each RUM event includes default attributes (such as view.url, device.type, geo.country) as well as additional metrics and attributes specific to each event type.

Default Attributes

Web RUM SDK automatically captures the following default attributes, applicable to all RUM event types.

Core Attributes

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

Device Attributes

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

Operating System Attributes

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

Browser Attributes

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

Geo-location Attributes

Attribute	Type	Description
`geo.country`	String	Country name
`geo.country_iso_code`	String	Country ISO code (e.g., `US`, `CN`)
`geo.country_subdivision`	String	First-level administrative division (e.g., US states, China provinces)
`geo.continent_code`	String	Continent ISO code (e.g., `EU`, `AS`, `NA`)
`geo.continent`	String	Continent name
`geo.city`	String	City name

Geo-location information is inferred by FlashCat backend based on client IP address. Precise GPS location is not collected on the client.

User Attributes

Attribute	Type	Description
`usr.id`	String	User unique identifier
`usr.name`	String	User-friendly name, displayed by default in RUM UI
`usr.email`	String	User email address. Displayed if no username is set

You can also add custom user attributes such as usr.plan, usr.role, etc. To set user information, see SDK Integration Guide.

Event-Specific Attributes

Different event types have specific attributes and metrics.

Session Attributes

Attribute	Type	Description
`session.id`	String	Session unique identifier
`session.type`	String	Session type (e.g., `user`, `synthetic`)
`session.is_active`	Boolean	Whether session is active
`session.initial_view.id`	String	Initial view ID in session
`session.initial_view.url`	String	Initial view URL in session
`session.initial_view.name`	String	Initial view name in session
`session.last_view.id`	String	Last view ID in session
`session.last_view.url`	String	Last view URL in session
`session.last_view.name`	String	Last view name in session
`session.has_replay`	Boolean	Whether session has replay enabled

View Timing Metrics

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

Attribute	Type	Description
`view.largest_contentful_paint`	Number (ns)	Largest Contentful Paint (LCP), render time of the largest visible content element in viewport
`view.first_input_delay`	Number (ns)	First Input Delay (FID), time from user’s first interaction to browser’s actual response
`view.cumulative_layout_shift`	Number	Cumulative Layout Shift (CLS), quantifies unexpected movement of visible elements in viewport
`view.interaction_to_next_paint`	Number (ns)	Interaction to Next Paint (INP), measures latency of all user interactions with the page

Navigation Performance Metrics

Attribute	Type	Description
`view.time_spent`	Number (ns)	Time user spent on this view
`view.loading_time`	Number (ns)	Time for page to fully load (triggered at `loadEventEnd`)
`view.first_contentful_paint`	Number (ns)	First Contentful Paint (FCP), time when browser first renders any text, image, non-blank canvas or SVG
`view.first_byte`	Number (ns)	Time to First Byte (TTFB), time from user initiating page load to browser receiving first byte of HTML document
`view.dom_interactive`	Number (ns)	Time when parser finished working on main document (`domInteractive`)
`view.dom_content_loaded`	Number (ns)	Time when initial HTML document is fully loaded and parsed
`view.dom_complete`	Number (ns)	Time when page and all sub-resources are ready (`domComplete`)
`view.load_event`	Number (ns)	Time when load event fired (`loadEventEnd`), indicating page fully loaded

Network Timing Metrics

Attribute	Type	Description
`view.redirect.duration`	Number (ns)	Time spent on redirects
`view.dns.duration`	Number (ns)	Time spent on DNS lookup
`view.connect.duration`	Number (ns)	Time spent establishing server connection
`view.ssl.duration`	Number (ns)	Time spent on TLS handshake
`view.request.duration`	Number (ns)	Time spent requesting HTML document
`view.response.duration`	Number (ns)	Time spent downloading HTML document
`view.in_foreground_periods.count`	Number	Number of times view was in foreground
`view.in_foreground_periods.duration`	Number (ns)	Total time view was in foreground

View Attributes

Attribute	Type	Description
`view.id`	String	View unique identifier
`view.url`	String	View URL
`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 view is active

Resource Timing Metrics

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

Attribute	Type	Description
`resource.duration`	Number (ns)	Total time to load resource
`resource.size`	Number (bytes)	Resource size
`resource.connect.duration`	Number (ns)	Time to establish server connection
`resource.ssl.duration`	Number (ns)	Time for TLS handshake (HTTPS only)
`resource.dns.duration`	Number (ns)	Time for DNS resolution
`resource.redirect.duration`	Number (ns)	Time for redirects
`resource.first_byte.duration`	Number (ns)	Time waiting to receive first byte of response
`resource.download.duration`	Number (ns)	Time to download response
`resource.render_blocking_status`	String	Resource render blocking status (`blocking`, `non-blocking`)
`resource.first_party`	Boolean	Whether resource is first-party (same domain as application)

Resource Attributes

Attribute	Type	Description
`resource.id`	String	Resource unique identifier
`resource.type`	String	Resource type (e.g., `xhr`, `fetch`, `css`, `js`, `image`, `font`, `media`)
`resource.method`	String	HTTP method (e.g., `GET`, `POST`, `PUT`, `DELETE`)
`resource.status_code`	Number	HTTP response status code
`resource.url`	String	Resource URL
`resource.url_host`	String	URL host part
`resource.url_path`	String	URL path part
`resource.url_query`	Object	URL query parameters, parsed as key-value pairs
`resource.url_scheme`	String	URL scheme (e.g., `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 (e.g., `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, containing message, code, locations and path

Long Task Attributes

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

Attribute	Type	Description
`long_task.duration`	Number (ns)	Long task duration
`long_task.is_frozen_frame`	Boolean	Whether it’s a frozen frame (duration exceeds 700ms)

Long task detection is only available in browsers that support the Long Tasks API (Chrome, Edge). Safari and Firefox don’t support this feature.

Error Attributes

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

Attribute	Type	Description
`error.id`	String	Error unique identifier
`error.source`	String	Error source (e.g., `console`, `network`, `source`, `logger`, `agent`, `webview`, `custom`, `report`)
`error.type`	String	Error type (in some cases, error code)
`error.message`	String	Concise, human-readable one-line error message
`error.stack`	String	Error stack trace or supplementary information
`error.issue_id`	String	Error issue unique identifier (same errors are grouped into the same issue)
`error.fingerprint`	String	Fingerprint for uniquely identifying 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

Network Error AttributesNetwork errors contain information about failed HTTP requests:

Attribute	Type	Description
`error.resource.status_code`	Number	HTTP response status code
`error.resource.method`	String	HTTP method (e.g., `GET`, `POST`)
`error.resource.url`	String	Resource URL
`error.resource.url_host`	String	URL host part
`error.resource.url_path`	String	URL path part
`error.resource.url_scheme`	String	URL scheme
`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`)

For more information about different JavaScript error types, see MDN documentation.

Action Attributes

Action Timing Attributes

Attribute	Type	Description
`action.loading_time`	Number (ns)	Action loading time
`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 Identification Attributes

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

Frustration Signals

RUM automatically detects user frustration signals, helping you understand problems users encounter in your application.

Attribute	Type	Description
`session.frustration.count`	Number	Total frustration signals in session
`view.frustration.count`	Number	Total frustration signals in 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 (rapid consecutive clicks)
`action.frustration.type:error_click`	String	Error click detected by RUM SDK (click that triggered an error)

Frustration signals are important indicators for identifying user experience issues. Dead clicks and rage clicks typically indicate UI response delays or interaction design problems.

UTM Attributes

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

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

Data Storage

Before uploading to FlashCat, data is temporarily stored in plaintext in the browser’s local storage (LocalStorage or SessionStorage).

Data Collection

SDK adds events to an in-memory batch buffer.

Local Caching

When network is unavailable, batches are retained in local storage.

Batch Upload

When network is available, data is sent to server in batches.

Auto Cleanup

Data exceeding certain time limits is automatically cleaned up to avoid excessive storage usage.

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

Data Upload

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

Batch Upload Triggers

Event count in batch reaches threshold
Batch size reaches threshold
Periodic upload (e.g., every 10 seconds)
Page unload (beforeunload event)

Upload Strategy

Strategy	Description
Beacon API	Preferred, ensures data isn’t lost when page unloads
XHR/Fetch Fallback	If Beacon API unavailable, uses XMLHttpRequest or Fetch API
Failure Retry	If upload fails, batch is retained in local storage until successfully sent
Data Compression	Batch data is compressed before upload to reduce network traffic

Privacy and Compliance

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

Configurable whether to use cookies and local storage

GDPR/CCPA Compliance

Supports user privacy opt-out mechanism

For detailed privacy configuration information, see Advanced Configuration.

More Information

SDK Integration

Learn how to integrate RUM SDK in Web applications

Advanced Configuration

Learn how to configure advanced SDK features

Compatibility

Learn about SDK browser and framework compatibility

Quick Start

Analytics

SDK Integration

Performance

Error Tracking

Explorer

Session Replay

Best Practices

Others

Default Attributes

Event-Specific Attributes

Data Storage

Data Upload

Batch Upload Triggers

Upload Strategy

Privacy and Compliance

IP Address Anonymization

Sensitive Data Filtering

Cookie and Storage Control

GDPR/CCPA Compliance

More Information

SDK Integration

Advanced Configuration

Compatibility

Quick Start

Analytics

SDK Integration

Performance

Error Tracking

Explorer

Session Replay

Best Practices

Others

​Default Attributes

​Event-Specific Attributes

​Data Storage

​Data Upload

​Batch Upload Triggers

​Upload Strategy

​Privacy and Compliance

IP Address Anonymization

Sensitive Data Filtering

Cookie and Storage Control

GDPR/CCPA Compliance

​More Information

SDK Integration

Advanced Configuration

Compatibility

Default Attributes

Event-Specific Attributes

Data Storage

Data Upload

Batch Upload Triggers

Upload Strategy

Privacy and Compliance

More Information