Content producers often want to understand the demographics of their audience. You can use Shared Storage to record user demographic data in a context where you have it, such as your first-party site, and then use aggregated reporting to include that data in reports from other sites, such as your embedded content.
The Shared Storage API is a Privacy Sandbox proposal for general purpose, cross-site storage, which supports many possible use cases. Private Aggregation API is an output available in Shared Storage that lets you aggregate cross-site data.
Try user demographic measurement
To experiment with user demographic measurement with Shared Storage and Private Aggregation, confirm you're using Chrome Canary and Dev M107 or later. Enable all the Ad privacy APIs under chrome://settings/adPrivacy
.
You can also enable Shared Storage with the --enable-features=PrivacySandboxAdsAPIsOverride,OverridePrivacySandboxSettingsLocalTesting,SharedStorageAPI,FencedFrames
flag in the command line.
Experiment with code samples
You may want to measure certain demographics of the users who have seen your content across different sites, for example age range or geographical location. In this example, the content ID, age group ID, and the geography ID dimensions are encoded into the aggregation key (bucket), and the count is used as the aggregatable value. The summary report generated will provide information such as "Approximately 391 users who have seen the content ID 123 are between the age of 18-39 and are from Europe."
In this example:
-
demographic-measurement.jsis loaded using a frame, and is responsible for loading the shared storage worklet. -
demographic-measurement-worklet.jsis the shared storage worklet that reads the demographics data in shared storage and sends a report using the Private Aggregation API.
(Runs at some point in time before the measurement is made to set the demographics data into Shared Storage)
function
getDemogrationsData
()
{
// Collect age group and continent data
return
{
ageGroup
,
continent
}
}
async
function
storeDemographics
()
{
const
{
ageGroup
,
continent
}
=
getDemographicsData
();
await
window
.
sharedStorage
.
set
(
'age-group'
,
ageGroup
);
await
window
.
sharedStorage
.
set
(
'continent'
,
continent
);
}
storeDemographics
();
async
function
measureDemographics
()
{
// Load the Shared Storage worklet
await
window
.
sharedStorage
.
worklet
.
addModule
(
'demographics-measurement-worklet.js'
);
// Run the demographics measurement operation
await
window
.
sharedStorage
.
run
(
'demographics-measurement'
,
{
data
:
{
contentId
:
'123'
}
});
}
measureDemographics
();
demographic-measurement-worklet.js
// Learn more about noise and scaling from the Private Aggregation fundamentals
// documentation on Chrome blog
const
SCALE_FACTOR
=
65536
;
/**
* The bucket key must be a number, and in this case, it is just the ad campaign
* ID itself. For more complex bucket key construction, see other use cases in
* this demo.
*/
const
AGGREGATION_KEY_MAP
=
{
ageGroupId
:
{
'18-39'
:
'1'
,
'40-64'
:
'2'
,
'65+'
:
'3'
,
},
continentId
:
{
africa
:
'1'
,
antarctica
:
'2'
,
asia
:
'3'
,
australia
:
'4'
,
europe
:
'5'
,
'north-america'
:
'6'
,
'south-america'
:
'7'
,
},
};
/**
* The aggregation key will be in the format of:
* contentId | ageGroupId | continentId
*
* For example, a user from Australia between the age of 40-64, who has
* seen the Content ID 321 will be represented by the key:
* 321 | 2 | 4 or 32124
*/
function
generateAggregationKey
(
contentId
,
ageGroup
,
continent
)
{
const
ageGroupId
=
AGGREGATION_KEY_MAP
.
ageGroupId
[
ageGroup
];
const
continentId
=
AGGREGATION_KEY_MAP
.
continentId
[
continent
];
const
aggregationKey
=
BigInt
(
`
${
contentId
}${
ageGroupId
}${
continentId
}
`
);
return
aggregationKey
;
}
class
DemographicsMeasurementOperation
{
async
run
(
data
)
{
const
{
contentId
}
=
data
;
// Read from Shared Storage
const
key
=
'has-reported-content'
;
const
hasReportedContent
=
(
await
sharedStorage
.
get
(
key
))
===
'true'
;
const
ageGroup
=
await
sharedStorage
.
get
(
'age-group'
);
const
continent
=
await
sharedStorage
.
get
(
'continent'
);
// Don't report if a report has been sent already
if
(
hasReportedContent
)
{
return
;
}
// Generate the aggregation key and the aggregatable value
const
bucket
=
generateAggregationKey
(
contentId
,
ageGroup
,
continent
);
const
value
=
1
*
SCALE_FACTOR
;
// Send an aggregatable report using the Private Aggregation API
privateAggregation
.
contributeToHistogram
({
bucket
,
value
});
// Set the report submission status flag
await
sharedStorage
.
set
(
key
,
true
);
}
}
// Register the operation
register
(
'demographics-measurement'
,
DemographicsMeasurementOperation
);
\
Engage and share feedback
Note that the Shared Storage API proposal is under active discussion and development and therefore subject to change.
We're eager to hear your thoughts on the Shared Storage API.
- Proposal: Review the detailed proposal .
- Discussion: Join the ongoing discussion to ask questions and share your insights.
Stay Informed
- Mailing List: Subscribe to our mailing list for the latest updates and announcements related to the Shared Storage API.
Need Help?
- Developer Support: Connect with other developers and get answers to your questions in the Privacy Sandbox Developer Support repository .
