The matching key

FlowProofs pairs a source ping with its destination ping using a shared reference. Use the same one at both ends, so it can tell they're the same record.

external_id: the reference you control

Every ping includes an external_id field, a value you choose, meant to identify one specific record. Send the same external_id in the source ping and the destination ping for the same real-world thing (the same call, the same order, the same form submission), and FlowProofs pairs them automatically.

A call ID from your voice agent.
An order number from your e-commerce platform.
A submission ID from your form tool.
Any ID your system already generates and can pass along at both points.

Choosing a good reference

The best reference is one your system already produces and can carry through the whole chain without extra work. Most tools expose some kind of record or execution ID you can reuse. Avoid anything that could repeat (like a plain incrementing counter reset per day) since a repeated ID could pair the wrong records together.

Matching on phone or email instead

Not every system has a clean shared ID available at both ends. If you can't pass one through, FlowProofs can match on a phone number or email address included in the match object instead, as long as the same contact's phone or email genuinely appears at both the start and the finish.

During onboarding, FlowProofs looks at the real pings you've actually sent and proposes whichever matching approach the data supports, so you never configure this blind.

Why this matters

Without a way to pair records, FlowProofs would only be able to compare raw counts ("12 started, 11 finished"). That's useful, but it can't tell you which record is missing. With a matching key, it can point at the exact call, order, or submission that never arrived, which is what actually lets you go fix it or tell your client what happened.

See the glossary if any of the field names above (body, header) are unfamiliar.