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Documentation Index

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Emitted when the user runs out of retries for a check that’s blocking confirmation, or when a hard-kill code (such as an anti-cloning attestation failure) terminates the session immediately. The payload carries the terminal failure_code plus the per-check retry counters so you can see which budget exhausted.

​
When it fires

This event fires once per session, at the moment the session reaches the failed status. Intermediate per-check failures while retries remain are not delivered as webhooks — they appear in the per-org audit log as session.check.failed and stay between the user and the Kayle app. Retry budgets:
CheckBudget
MRZ scanUnlimited (client-side; failures never reach the server)
NFC chip read3 retries
Liveness capture3 retries
document_anti_cloning_attestation_failed is a hard-kill code: it terminalizes the session immediately on the first failure regardless of retry counters.

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Payload

{
  "type": "verification.session.failed",
  "metadata": {
    "contract_version": 1,
    "event_id": "evt_...",
    "verification_session_id": "vs_..."
  },
  "data": {
    "failure_code": "document_chip_authentication_failed",
    "nfc_tries_used": 3,
    "liveness_tries_used": 0
  }
}

​
Fields

​
type
string
Always verification.session.failed.
​
metadata.contract_version
number
The share-contract version the session was created against.
​
metadata.event_id
string
Unique event ID. Idempotency-key candidate — the same event reuses this ID on retries and replays.
​
metadata.verification_session_id
string
The session that terminalized.
​
data.failure_code
string
Reason Kayle could not confirm the session. One of:
  • document_authenticity_failed
  • document_active_authentication_failed
  • document_chip_authentication_failed
  • document_anti_cloning_attestation_failed
  • document_data_invalid
  • liveness_failed
  • selfie_face_mismatch
Failed-session payloads do not include claims, biometrics, or risk scores.
​
data.nfc_tries_used
number
How many NFC chip-read retries (0..3) the session consumed before terminalizing.
​
data.liveness_tries_used
number
How many liveness retries (0..3) the session consumed before terminalizing.

​
Handler outline

if (event.type === "verification.session.failed") {
  const { verification_session_id, event_id } = event.metadata;
  if (await alreadyProcessed(event_id)) return;

  await recordIdentityAssuranceFailure({
    sessionId: verification_session_id,
    failureCode: event.data.failure_code,
    nfcTriesUsed: event.data.nfc_tries_used,
    livenessTriesUsed: event.data.liveness_tries_used,
  });
}