> ## Documentation Index
> Fetch the complete documentation index at: https://docs.kalshi.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Drop Copy Session

> Recover missed margin execution reports and query historical order events

> [!WARNING]
>
> **This is not a traditional drop copy session.** Kalshi's Drop Copy uses a request-response pattern for querying historical execution reports. For a real-time streaming feed, use a [Listener Session](/fix-margin/listener-sessions.md) on KalshiRT instead.

> [!NOTE]
>
> Historical execution-report replay through EventResendRequest (35=U1) requires allowlisting for your user account on both `KalshiNR` and `KalshiDC` sessions. Contact [institutional@kalshi.com](mailto:institutional@kalshi.com) to request access. Requests from accounts that are not allowlisted are rejected with EventResendReject (35=U3), reason `5` (NOT\_ENABLED). Allowlisting does not backfill earlier events.

Lookback window is limited to the last 3 hours. Only ExecutionReport (35=8) messages are returned. Rejects and pending orders (ExecID `"-1;-1"`) are excluded.

> [!NOTE]
>
> Resent messages have new FIX sequence numbers, different from their original numbers on the trading session. Use ExecID to reconcile.

## EventResendRequest (35=U1)

Request execution reports within a specified ExecID range.

| Tag | Name | Description | Required |
| - | - | - | - |
| 21001 | BeginExecID | Starting ExecID (inclusive) | Yes |
| 21002 | EndExecID | Ending ExecID (inclusive). Defaults to latest ExecID if omitted. | No |

**Example:**

```fix theme={null}
8=FIXT.1.1|35=U1|21001=12345;67890|21002=12350;67895|
```

## EventResendComplete (35=U2)

Sent after all requested events have been resent.

| Tag | Name | Description | Required |
| - | - | - | - |
| 45 | RefSeqNum | MsgSeqNum of the EventResendRequest | Yes |
| 21003 | ResendEventCount | Total number of events resent | Yes |

## EventResendReject (35=U3)

Sent when a resend request cannot be fulfilled.

| Tag | Name | Description | Required |
| - | - | - | - |
| 45 | RefSeqNum | MsgSeqNum of the EventResendRequest | Yes |
| 21004 | EventResendRejectReason | Rejection code: `1`=Too many resend requests, `2`=Server error, `3`=BeginExecID too small (outside window), `4`=EndExecID too large, `5`=User not allowlisted for historical replay | Yes |


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