Meta, Google, and LinkedIn use the conversion data you send them to train their bidding algorithms. If half of your conversions arrive without enough identifiers to map back to a real user, the algorithm is effectively guessing about half the time. Customers running Cometly’s Conversion API typically see match quality scores jump from 4–6 to 8.5–9.3, which translates to dramatically better cost-per-customer on the same ad spend.
What goes into a high match score
Each ad platform has its own scoring model, but they all reward the same handful of identifiers: hashed email, hashed phone, hashed first/last name, IP address, user agent, and the platform-specific click ID (`fbclid`, `gclid`, `li_fat_id`). The more identifiers you send per event, and the cleaner each one is, the higher the match score.
Cometly automatically hashes and forwards everything it captures from the Comet Pixel and the integrated CRMs — so the match score is high without your team having to manually configure each field.
- Hashed email — the highest-impact single identifier
- Hashed phone — adds 10–20 points of match quality on most accounts
- IP + user agent — the floor that catches anonymous events
- Click ID (`fbclid`, `gclid`, `li_fat_id`) — captured at landing, reused at conversion
- Event ID — used to dedupe between the in-page pixel and the server-side event
Which events to send
Send everything the platform supports, but optimize on the deepest event you have meaningful volume for. For most B2B SLG teams that’s Demo Booked or MQL; for PLG teams it’s Trial Converted or New Customer. The deeper the event, the higher the value the platform optimizes against — and the more qualified the audience it builds.
If you don’t yet have 50 weekly conversions on the deeper event, optimize on the closest mid-funnel event you do have volume for, and use the deeper event as a secondary signal for retargeting and lookalikes.
What to watch for.
- Sending only browser-side events
iOS, ITP, and ad blockers eat half your in-page pixel data. Always pair the pixel with server-side Conversion API events.
- Forgetting to dedupe
If both the in-page pixel and the server-side event fire without a shared event_id, every conversion gets counted twice. Cometly dedupes automatically — verify it’s on.
- Optimizing on Lead instead of MQL or Demo
Lead is the cheapest, lowest-quality signal. Push deeper events whenever volume allows.
- Skipping the click ID capture
Without `fbclid`/`gclid`/`li_fat_id` on the conversion event, match quality drops sharply. Capture them as hidden fields on every landing page.
Recap.
- Conversion API sends events server-side — no ad blockers, no consent gaps
- Hashed first-party data (email, phone, IP, user agent) drives the match score up
- Push downstream events back to platforms — qualified lead, demo attended, paying customer
- Optimize ad sets toward the deeper-funnel event whenever volume allows
- Cometly handles dedupe between the in-page pixel and the server-side event automatically