Match Keys

Match keys are identifiers you can share with conversion events and are crucial to help match conversions to a Reddit Ads engagement like a view or click.

Customer match keys and identifiers

Customer match keys are user identifiers that help improve conversion measurement, which can:

• Strengthen attribution. Improve attribution accuracy and capture more conversions with reliable identifiers, especially email addresses. 
• Enhance cross-device tracking. Attribute conversions more accurately by tracking user interactions across multiple devices and platforms.
• Improve retargeting. Create more precise and reliable retargeting audience lists based on specific user actions, leading to higher conversion rates.

At a minimum, pass email addresses to share cross-platform conversions and improve measurement and attribution.

These values can be passed prehashed. Learn more about normalizing and hashing match keys.

Parameter	Description
Email address	A user's unique email account. This is a highly available persistent signal that is resilient to signal loss. We strongly recommend enabling it to track cross-platform conversions and strengthen attribution. Learn how to pass this auto-advanced matching or manual advanced matching. Example: example@email.com
Reddit click ID	A unique click ID to attribute click conversions more accurately.  This is recommended for all available conversion events. Learn how to implement for CAPI and test for persistence. Examples: https://example.com?rdt_cid=12345 https://example.com?utm_source=reddit&utm_medium=social&rdt_cid=12345
Phone number	A user's phone number in E.164 format. Example: +15554441234
Mobile advertising ID (MAID)	A user's unique mobile advertising ID. This is either Android's AAID (Android Advertising ID) or Apple's IDFA (Identifier for Advertisers). Note: This is case-sensitive. Ensure the unhashed value is lowercase for AAID and uppercase for IDFA. Learn more about sending hashed values. Examples: AAID: 38400000-8cf0-11bd-b23e-10b96e40000d IDFA:  8A2E4F6D-0852-4B2A-B9D5-79334DE14B16
External ID	An advertiser-assigned custom identifier that helps improve attribution accuracy for events from all action sources. We recommend passing an external ID that is unique to a single user. Example: customer12345
Reddit UUID	A unique ID generated by the Reddit Pixel when it's installed on your website. Example: 1677712978045.b8f7eb7d-b357-437b-8bd3-e1c8166c7132

Device matching identifiers

Device matching identifiers help attribute view conversions, especially when a click ID or customer match keys aren't passed. We recommend passing as many parameters as possible, but IP address must be passed at the minimum.

Parameter	Description
IP address	The unique ID assigned to the user's device on the internet. Example: 192.168.0.1
User agent	The software agent representing the user. Example: Chrome/98.0.4758.102
Screen dimensions	The width and height of the user's display. Example: 1920x1080

Set up match keys

There are four ways to set up match keys:

• Send with Google Tag Manager
• Send in a request to the Conversions API
• Add to Pixel code
• Add to Pixel code in Shopify

Some integrations require a little technical skill. If that's not in your wheelhouse, you might want to ask the right technical support person on your team for assistance.

Best practices

• Send as many match keys as possible. For example, if you’ve set up omnichannel attribution for CAPI, offline events should be sent with hashed emails and phone numbers—but no device identifiers, click ID, UUID, or MAIDs.
• Enable auto-advanced matching. Automatically collect and hash match keys to improve measurement, retargeting, and conversion rates for Pixel events.