Real-time inventory

Part of Build tax center experiences. Taxbit recalculates an account's inventory in the background after each transaction it processes, so a read straight after a send can come before the recalculation. This page shows two ways to know the inventory has caught up: a webhook that tells you, or a check you run yourself.

The newest transaction for an account is usually reflected in under a second when transactions arrive in order. A transaction that lands earlier in an account's history is a historical change and has no SLA. See SLAs & async behavior.

By the end of this page your app refreshes an account's inventory only once it reflects the latest transaction.

Before you begin

• A bearer token. See Authenticate your tenant.
• Transactions flowing for the account. See Set up inventory and gains.
• For the webhook, a subscription and an endpoint that receives deliveries. See the Webhooks guide.

Refresh on the webhook

With a webhook subscription, Taxbit delivers an INVENTORY_UPDATE event when an account's inventory changes. Each delivery wraps its events in a data array; iterate over it rather than reading only the first entry.

{
  "timestamp": "2026-07-15T13:05:41Z",
  "data": [
    {
      "id": "evt_3f81c2d0",
      "event_type": "INVENTORY_UPDATE",
      "account_id": "acct_5f2e7d10",
      "latest_transaction_datetime": "2026-07-15T13:05:40Z",
      "update_from_datetime": "2026-07-15T13:05:40Z",
      "latest_transaction_id": "trade_88214",
      "update_from_transaction_id": "trade_88214"
    }
  ]
}

When it arrives, re-read the account's inventory with GET /v1/inventory/summaries or GET /v1/inventory, as in Retrieve inventory. update_from_datetime is the start of the affected range: figures from that point forward may have changed, including gains you've already shown. When transactions were deleted, the event carries no *_transaction_id fields, so rely on the datetimes. The Webhooks guide has the full event reference.

Check by polling

Without a subscription, compare what the inventory reflects with what you sent. The summary in GET /v1/inventory and in each entry of GET /v1/inventory/summaries carries:

• latest_transaction_datetime: the datetime of the latest transaction for the asset.
• client_modified_by_transaction_id: your id for that transaction.

curl -G $BASE_URL/v1/inventory/summaries \
  -H "Authorization: Bearer $TOKEN" \
  --data-urlencode "account_id=acct_5f2e7d10"

{
  "data": [
    {
      "asset": { "code": "ETH", "name": "Ethereum", "type": "Crypto", "uuid": "b7a005b5-f4d5-44ea-ae80-d4f9e8313558" },
      "summary": {
        "total_quantity": "1.5",
        "total_quantity_with_cost_basis": "1.5",
        "total_cost": "4875.00",
        "average_unit_cost": "3250.00",
        "latest_transaction_datetime": "2026-07-15T13:05:40Z",
        "client_modified_by_transaction_id": "trade_88214"
      }
    }
  ]
}

When those match the last transaction you sent for that asset, the inventory reflects it. If they don't yet, read again after a short wait.

Where to go next

Display unrealized gain/loss turns current inventory into gain and loss figures at your prices. Back to Build tax center experiences.