The Events API serves as an auditable event history trail of how Mercury resources, like Transactions, transition over time.

How Events Work

Events use the JSON Merge Patch standard (RFC 7396) to represent changes. Events are available for 90 days after they occur.

Event Fields

Each event contains the following fields:

id: A unique identifier (UUID) for this event. Use this to track which events you've already processed.
resourceType: The type of resource that was modified.
resourceId: The ID of the specific resource that changed.
operationType: The type of change that occurred:
- "create" - A new resource was created
- "update" - An existing resource was modified
- "delete" - A resource was deleted
resourceVersion: An integer representing the version of the resource after this change. Starts at 1 for new resources and increments with each update.
occurredAt: The timestamp when this event occurred, in ISO 8601 format.
changedPaths: An array of field paths (e.g., ["note", "status"]) indicating exactly which fields were modified. This makes it easy to quickly identify what changed without parsing the entire patch.
mergePatch: A JSON object containing only the fields that changed and their new values. Following RFC 7396, this is a partial representation that, when applied to the previous state, produces the new state.
previousValues: A JSON object containing the previous values of only the changed fields. This is null for create operations since there were no previous values. For updates, it mirrors the structure of mergePatch but with the old values.

Example

When a transaction's status changes from "pending" to "sent" and the posting date is set, the event would look like:

{
  "id": "bfa85eaa-afab-11f0-8fea-17d650f2306e",
  "resourceType": "transaction",
  "resourceId": "1d3042b6-af63-11f0-89d2-3503f2fcfef7",
  "operationType": "update",
  "resourceVersion": 2,
  "occurredAt": "2025-01-01T00:00:00.000000Z",
  "changedPaths": [
    "status",
    "postedAt"
  ],
  "mergePatch": {
    "postedAt": "2025-01-01T00:00:00.000000+00:00",
    "status": "sent"
  },
  "previousValues": {
    "postedAt": null,
    "status": "pending"
  }
}

Below are the following resources and fields that are supported through the Events API.

Transaction

amount - Transaction amount (positive for credits, negative for debits)
bankDescription - Description provided by the bank or payment network
categoryData - Transaction categorization information
- customCategory - User-defined custom category
  - id - Unique identifier for the custom category
  - name - Display name of the custom category
- mercuryCategory - Mercury's auto-assigned category based on merchant data
estimatedDeliveryDate - Expected date when the transaction will complete
externalMemo - Memo or reference text from the sender/external source
failedAt - Timestamp when the transaction failed (if applicable)
note - User-added note or memo for internal reference
postedAt - Timestamp when the transaction posted to the account
reasonForFailure - Explanation for why the transaction failed (if applicable)
status - Current transaction state (pending, sent, cancelled, failed, reversed, blocked)