Webhooks

Payload Reference

Detailed payload schemas for each webhook event type.

Every webhook delivery wraps the event-specific data in a standard envelope:

json

{
  "event": "<event_type>",
  "timestamp": "2026-02-11T10:30:00.000Z",
  "data": { ... }
}

Below are the full payload schemas for each event type.

`delta.verified`

The primary webhook event. Fired after each delta is independently verified. Contains the complete proof packet, original delta data, verification results, period summary, and usage information.

json

{
  "event": "delta.verified",
  "timestamp": "2026-02-11T10:30:12.456Z",
  "data": {
    "receiptId": "rcpt_a1b2c3d4e5f6",
    "deltaIndex": 1042,
    "status": "verified",
    "verifiedAt": "2026-02-11T10:30:12.000Z",
    "verificationId": "ver_x7y8z9",

    "delta": {
      "customerId": "cust_8xKj2m",
      "amount": -42.50,
      "reason": "usage_charge",
      "referenceId": "inv_20260211_001",
      "metadata": {
        "plan": "growth",
        "region": "us-east-1"
      },
      "submittedAt": "2026-02-11T10:30:00.000Z"
    },

    "proof": {
      "proofHash": "0x8f3a9b2c1d4e5f6a7b8c9d0e1f2a3b4c5d6e7f8a9b0c1d2e3f4a5b6c7d8e9f",
      "contentHash": "0x2d4e7f1a3b5c8d9e0f1a2b3c4d5e6f7a8b9c0d1e2f3a4b5c6d7e8f9a0b1c2d",
      "itemHashes": [
        "0x2d4e7f1a3b5c8d9e0f1a2b3c4d5e6f7a8b9c0d1e2f3a4b5c6d7e8f9a0b1c2d",
        "0x9f1a3c5e7b2d4f6a8c0e1b3d5f7a9c2e4b6d8f0a1c3e5b7d9f2a4c6e8b0d1f"
      ],
      "previousProofHash": "0x1c7b2e4a6d8f0b3c5e7a9d1f3b5c7e9a2d4f6b8c0e2a4d6f8b1c3e5a7d9f0b"
    },

    "verification": {
      "verified": true,
      "latencyMs": 1204,
      "discrepancies": []
    },

    "period": {
      "id": "per_2026_02",
      "deltaCount": 1042,
      "netDelta": -15780.25
    },

    "usage": {
      "plan": "growth",
      "includedDeltas": 10000,
      "consumedDeltas": 1042,
      "remainingDeltas": 8958,
      "overageRate": 0.02
    }
  }
}

Field Reference

Top-level fields

Field	Type	Description
`receiptId`	`string`	Unique identifier for this verified delta
`deltaIndex`	`integer`	Global sequence number for this delta
`status`	`string`	Verification status — always `"verified"` for this event
`verifiedAt`	`string`	ISO 8601 timestamp of when verification completed
`verificationId`	`string`	Identifier for the verification transaction

`delta` object

Field	Type	Description
`customerId`	`string`	Your customer identifier
`amount`	`number`	The delta amount (positive or negative)
`reason`	`string`	Reason code for the delta
`referenceId`	`string`	Your external reference identifier
`metadata`	`object`	Arbitrary metadata you attached to the delta
`submittedAt`	`string`	ISO 8601 timestamp of when the delta was submitted

`proof` object

Field	Type	Description
`proofHash`	`string`	Merkle root of the batch containing this delta
`contentHash`	`string`	Hash of this individual delta's payload
`itemHashes`	`string[]`	All content hashes in the batch
`previousProofHash`	`string`	Proof hash of the preceding delta (forms the chain)

`verification` object

Field	Type	Description
`verified`	`boolean`	Whether verification passed
`latencyMs`	`integer`	Time from submission to verification in milliseconds
`discrepancies`	`array`	List of any discrepancies found (empty when verified)

`period` object

Field	Type	Description
`id`	`string`	Period identifier
`deltaCount`	`integer`	Total deltas in the current period so far
`netDelta`	`number`	Net sum of all delta amounts in the period

`usage` object

Field	Type	Description
`plan`	`string`	Current plan name
`includedDeltas`	`integer`	Total deltas included in the plan
`consumedDeltas`	`integer`	Deltas used so far this period
`remainingDeltas`	`integer`	Deltas remaining before overage
`overageRate`	`number`	Cost per delta beyond the included amount

`delta.stored`

Fired when delta hashes have been permanently stored in the verification layer.

json

{
  "event": "delta.stored",
  "timestamp": "2026-02-11T10:30:15.789Z",
  "data": {
    "batchId": "bat_m4n5o6p7",
    "itemCount": 12,
    "proofHash": "0x8f3a9b2c1d4e5f6a7b8c9d0e1f2a3b4c5d6e7f8a9b0c1d2e3f4a5b6c7d8e9f",
    "storedAt": "2026-02-11T10:30:15.000Z",
    "verificationId": "ver_x7y8z9",
    "itemHashes": [
      "0x2d4e7f...",
      "0x9f1a3c..."
    ]
  }
}

Field	Type	Description
`batchId`	`string`	Unique batch identifier
`itemCount`	`integer`	Number of items stored in this batch
`proofHash`	`string`	Merkle root of the stored batch
`storedAt`	`string`	ISO 8601 timestamp of storage confirmation
`verificationId`	`string`	Verification transaction identifier
`itemHashes`	`string[]`	Content hashes of all items in the batch

`checkpoint.verified`

Fired at period-end when all deltas are locked into a single verifiable root.

json

{
  "event": "checkpoint.verified",
  "timestamp": "2026-02-28T23:59:59.999Z",
  "data": {
    "checkpointId": "chk_q8r9s0t1",
    "periodId": "per_2026_02",
    "rootHash": "0xabcdef1234567890abcdef1234567890abcdef1234567890abcdef1234567890",
    "deltaCount": 9847,
    "netDelta": -142580.75,
    "firstDeltaIndex": 1,
    "lastDeltaIndex": 9847,
    "verifiedAt": "2026-02-28T23:59:59.000Z",
    "verificationId": "ver_u2v3w4"
  }
}

Field	Type	Description
`checkpointId`	`string`	Unique checkpoint identifier
`periodId`	`string`	The period this checkpoint covers
`rootHash`	`string`	Single root hash of all deltas in the period
`deltaCount`	`integer`	Total deltas in the period
`netDelta`	`number`	Net sum of all delta amounts
`firstDeltaIndex`	`integer`	Sequence number of the first delta in the period
`lastDeltaIndex`	`integer`	Sequence number of the last delta in the period
`verifiedAt`	`string`	ISO 8601 timestamp of verification
`verificationId`	`string`	Verification transaction identifier

`fact.verified`

Fired when a fact has been committed and verified.

json

{
  "event": "fact.verified",
  "timestamp": "2026-02-11T14:22:33.100Z",
  "data": {
    "factId": "fct_d5e6f7g8",
    "bucketId": "bkt_h9i0j1k2",
    "contentHash": "0x3e5a7c9b1d3f5a7c9b1d3f5a7c9b1d3f5a7c9b1d3f5a7c9b1d3f5a7c9b1d3f",
    "proofHash": "0xf0e1d2c3b4a5f0e1d2c3b4a5f0e1d2c3b4a5f0e1d2c3b4a5f0e1d2c3b4a5f0e1",
    "verifiedAt": "2026-02-11T14:22:33.000Z",
    "verificationId": "ver_l3m4n5",
    "fact": {
      "key": "balance_snapshot",
      "value": "98425.50",
      "metadata": {
        "source": "nightly_reconciliation"
      },
      "submittedAt": "2026-02-11T14:22:30.000Z"
    }
  }
}

Field	Type	Description
`factId`	`string`	Unique fact identifier
`bucketId`	`string`	The bucket this fact belongs to
`contentHash`	`string`	Hash of the fact data
`proofHash`	`string`	Proof hash for the verification
`verifiedAt`	`string`	ISO 8601 timestamp of verification
`verificationId`	`string`	Verification transaction identifier
`fact`	`object`	The original fact data (key, value, metadata, submittedAt)

Next Steps

Signature Verification — Authenticate webhook payloads
Autonomous Agent Pattern — Build agents that react to these events

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Last updated February 11, 2026

Event Types

Signature Verification

delta.verified#

Field Reference#

Top-level fields#

delta object#

proof object#

verification object#

period object#

usage object#

delta.stored#

checkpoint.verified#

fact.verified#

Next Steps#

`delta.verified`

Field Reference

Top-level fields

`delta` object

`proof` object

`verification` object

`period` object

`usage` object

`delta.stored`

`checkpoint.verified`

`fact.verified`

Next Steps