Check your Meta Conversions API payload
Paste a server event and this checks the three things that decide whether CAPI helps or hurts: a shared event_id so it deduplicates against the Pixel rather than doubling your conversions, an exactly-cased standard event name, and user_data that was normalized before it was hashed. That last one is where nearly every low match quality score comes from, because a malformed value produces a perfectly valid hash that matches nothing and errors nowhere.
Free30 minutesNo obligation
Check a Meta Conversions API payload
Paste a server event and this checks the things that decide whether it works: a shared event_id so it deduplicates against the Pixel, correctly cased standard event names, and user_data that was normalized before it was hashed — which is where nearly every low match quality score comes from.
Paste a CAPI payload and press Check. Everything happens in your browser. Nothing is sent anywhere.
CAPI checker · what breaks
What this tool is for — CAPI checker
- 01
Your purchase count looks roughly double
The signature of two paths counting independently.
- 02
Match quality is low and you don't know why
It's almost always normalization rather than coverage.
- 03
You just added CAPI
And want it checked before it teaches bidding something wrong.
CAPI checker · the fix
What you get out of it — CAPI checker
A deduplication verdict
Whether event_id is present and whether the event name will match.
Normalization findings
For email and phone, with the specific problem named.
The three missing fields
external_id, fbc and fbp, flagged when absent.
CAPI checker · architecture
Why CAPI without deduplication is worse than no CAPI
Adding a second path to a setup that can't relate the two is the most common CAPI failure, and it makes your data worse rather than better.
- 1
Two paths, two IDs, two conversions
Both events are valid, both process successfully, and Meta has no way to know they're one sale.
- 2
Bidding learns the wrong value
Told each click produces two purchases, it bids accordingly, and reported ROAS looks excellent until someone checks the bank.
- 3
Platform integrations mint their own IDs
A one-click CAPI integration has no knowledge of the event ID your container already generates.
- 4
The indicator is the only visible signal
And it's in a screen most accounts never open.
CAPI checker · diagnose
What this tool cannot tell you — CAPI checker
Stated up front, because a tool that implies more confidence than it has is worse than no tool. These are checks you have to run yourself.
- 01
Whether the browser Pixel sends the same ID
Use the deduplication checker with both payloads. One side alone can't prove a match.
- 02
Whether values were normalized before hashing
A hashed value is opaque. This is precisely why that failure is so common and so invisible.
- 03
Whether a third integration is also sending
Partner, app and container is three paths for one order, and one payload can't reveal that.
- 04
Your actual match quality score
That's in Events Manager, per event, read over seven days.
CAPI checker · prove
How to confirm the result — CAPI checker
Against your own records, not against the tool's output.
Source of truth
your backend order records, matched on order ID
- Deduplicated indicator visible on Purchase across a full week.
- Identical event_id confirmed on both paths for one real order.
- Match quality at 8 or above on the primary conversion.
- Purchase count within a few percent of backend orders.
- Reconciled over a fully closed window, matched per record rather than on totals.
- Re-checked after your next site release, which is when most breaks happen.
CAPI checker · free audit
What we check in the free audit
- Whether the browser Pixel sends the same ID
- Whether values were normalized before hashing
- Whether a third integration is also sending
- Your actual match quality score
Checked against
your backend order records, matched on order ID
Free30 minutesNo obligation
CAPI checker · when not to buy
Why this isn't gated — CAPI checker
There's no email form in front of it, and that's deliberate.
- A tool you have to pay for with your contact details is a lead form wearing a costume. If this is useful, it should be useful without a transaction.
- Everything it does runs in your browser. There is no endpoint, so there is nothing for us to collect even if we wanted to — open your network tab and check.
- It will tell you when you don't have a problem. That outcome costs us a sale and happens regularly, which is the point of publishing it rather than putting it behind a call.
- If it does find something and you'd rather fix it yourself, the reference pages on this site cover the how. Hiring us is one option, not the conclusion.
CAPI checker · what we deliver
What it checks
event_id
Present or not. Its absence means every conversion is counted twice.
event_name
Against Meta's standard list, including a case check — deduplication matches name and ID together.
event_time
Including the millisecond mistake, which lands the event far in the future.
user_data normalization
Email lowercased and trimmed, phone in E.164 with no punctuation, or already hashed.
Pricing
Pick the package that fits your ad spend
Browser-side starter
$400One-time fee · lifetime ownership
If the tool found something and you'd rather not fix it yourself: we repair the root cause in your existing setup and verify it on a live conversion.
- Root cause fixed, not worked around
- Verified on a live conversion
- Reconciled against your own records
- Written handover
1st-party server-side
Recommended$800One-time fee · most popular
Removes the class of failure rather than the instance. Money events from your own records through a first-party container on your subdomain.
- First-party server container on your own subdomain
- Events from your records, not the browser
- Deduplicated on a shared event ID at every destination
- First-party cookies beyond Safari's 7-day cap
- 95%+ accuracy and 8+ Meta EMQ, guaranteed in writing
Full 1st-party stack
$1,800One-time fee · lifetime ownership
Every paid channel server-side plus the offline loop, with monitoring so the next break surfaces in days rather than at quarter end.
- Everything in 1st-party server-side
- Pinterest, Snapchat, Reddit and LinkedIn CAPI
- CRM and offline conversion loop
- Refunds and cancellations corrected wherever each platform allows it
- Monitoring on every destination
FAQ
CAPI checker questions, answered
No. It flags the parameters that are missing or malformed. The score itself is Meta's and takes several days to move after a change.
Because a hash is opaque — it can't be checked for normalization. That's exactly why hashing a malformed email is such a common and invisible failure.
Nothing leaves your browser. Redact if you prefer; the tool can still tell you whether they look hashed.
A missing event_id, if both paths are live. That means everything is counted twice and bidding has learned a click is worth double.
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