Data stream ID dimension
Data stream ID is the dimension that records the numeric identifier of the GA4 data stream an event came from. A GA4 property can have web, Android, and iOS streams, and each event is stamped with its origin stream_id. It is the stable machine key for splitting reports by platform source, distinct from the editable stream name. It is configuration metadata, not anything about the visitor.
What this means
A GA4 property collects from one or more data streams — typically a web stream plus optional Android and iOS app streams. Every event records the numeric stream_id of its source. The data stream ID dimension surfaces that key so you can isolate, say, web events from app events within one property.
It is the machine-stable counterpart to the friendly stream name shown in the UI.
ID versus name
Stream names are editable labels; the stream ID is a fixed numeric key assigned when the stream is created. Reports and exports that reference stream_id keep working even after a stream is renamed, whereas filters keyed on the name break.
Use the ID for durable segmentation and the name only for readability in dashboards.
- Numeric key of the originating data stream
- One property may have web + app streams
- Stable across stream renames, unlike the name
How it appears in analytics and logs
A data stream ID value identifies the originating stream. Unexpected stream IDs in a report mean events are arriving from a stream you did not expect to be active.
Diagnostic use case
Use data stream ID to split a property's data by which web or app stream produced it, using a stable key that survives stream renames.
What WebmasterID can help detect
WebmasterID can attribute events to the originating site or app at the first-party layer, so multi-stream data stays cleanly separated without third-party tracking.
Common mistakes
- Filtering by stream name and breaking reports after a rename.
- Confusing the data stream ID with the GA4 measurement ID.
- Assuming one property maps to exactly one stream.
Privacy and accuracy notes
Data stream ID is property configuration metadata, not a visitor attribute. WebmasterID separates streams by first-party site context, never by a personal identifier.
Related pages
- Stream name dimension
The stream name dimension reports which data stream sent a hit — for example a website stream or a specific app stream within the same GA4 property. GA4 derives it from the stream configuration each hit is tagged to. It is essential for separating platforms or sites that share one property, and it pairs with the numeric stream ID; relying on the editable name alone for joins is fragile, since names can change while IDs do not.
- Platform dimension (web, Android, iOS)
Platform is the dimension that labels the broad surface an event came from — web, Android, or iOS — based on which data stream collected it. In a property that mixes a website and apps, it is the first cut for comparing surfaces. It is coarser than device category (which splits desktop/mobile/tablet within web) and complements the data stream ID, which is the precise per-stream key.
- Platform dimension: web, Android, or iOS
Platform is the dimension that records the broad surface a hit came from: web, Android, or iOS. In GA4 it is determined by the data stream the event arrived through, since a property can combine app and web streams. It is coarser than the operating-system dimension and is the right axis for comparing app versus web behaviour — but mixing app-only and web-only metrics across platforms is a frequent reporting error.
- Multi-site analytics
Separate data by originating site or stream.
Sources and verification notes
- Google Analytics Help — [GA4] Set up a data streamDocuments data streams and that a property can have several.
- GA4 Data API — Schema (dimensions)Lists stream-scoped dimensions available via the API.
Last reviewed 2026-06-24. Facts are checked against primary/official sources where available; uncertain specifics are marked “Data not yet verified” rather than guessed.