What Reddit's signal quality webinar taught me about getting more from paid social

Yesterday I attended a Reddit Ads webinar focused on signal quality and what it actually means for campaign performance. Here is what I learned and what it means for how we approach Reddit activity for our clients.

Signal quality is, in short, the accuracy, completeness, and reliability of the conversion data you send to Reddit. The better your signals, the more the platform's algorithm has to work with, and the better your results. Poor signal quality leads to higher CPAs, weaker attribution, and an algorithm working blind. Good signal quality leads to smarter optimisation, lower CPAs, and improved measurement across the board.

The headline stat that stuck with me: running a dual Pixel and Conversions API (CAPI) setup delivers a 35% increase in matched conversion events and a 25% reduction in CPA compared to running Pixel alone.

What signals actually are

There are two types of signals Reddit uses. Conversion signals are actions taken on your website, such as a purchase, sign up, or add to cart. Attribution signals are the identifying details that help Reddit match a conversion to an actual Redditor, things like IP address and hashed email.

Reddit collects these through two mechanisms. The Pixel operates browser-side, and CAPI is a server-to-server integration that is more resilient to signal loss caused by ad blockers, cookie restrictions, and cross-device behaviour. Running both together gives you the most complete picture.

The funnel mapping point most advertisers miss

My main takeaway from the webinar was around full funnel event mapping. Most advertisers only send a Purchase or Lead event, which means Reddit sees the final action and nothing else. Map conversion events to each stage of the funnel and the algorithm learns from the entire customer journey, not just the end point. That feeds directly into bottom of funnel performance.

Reddit recommends mapping at least one event per stage. Awareness sits at PageVisit. Consideration covers ViewContent, Search, AddToWishlist, and AddToCart. Conversion captures Purchase, Lead, and SignUp. By including those softer, upper funnel actions, you give the algorithm far more information about customers and their journey, and that learning compounds over time.

Match quality and how Reddit scores it

Launched in April 2025, Reddit's Match Quality Score (MQS) gives each conversion event a score out of ten in Events Manager. It measures how effectively your signals can be matched back to Reddit users, taking into account coverage, data quality, and the weight of each match key.

Email is the most important match key, being persistent across devices and bridging cross-platform attribution. IP address and phone number round out the core set. Supporting identifiers including Click ID, External ID, and Device ID can boost your score but will not penalise you if absent.

You can find your MQS in Events Manager under the Raw Events Table. Click any event for a full diagnostic breakdown with prioritised recommendations.

Three things worth doing this week

First, check your Match Quality Scores for key optimisation events. If any are below seven, action the top recommendation showing in Events Manager.

Second, enable Auto Advanced Matching on your Pixel if it is not already on. It takes thirty seconds, requires no engineering resource, and has an immediate impact on match rates.

Third, if you are currently running Pixel only, start the CAPI conversation. There are three integration routes: direct server-to-server integration (best for teams with engineering resource, four to eight weeks), via a CDP or tag manager such as Tealium or Segment (two to four weeks), or through a native commerce platform integration for Shopify or WooCommerce (one to two weeks, lowest effort).