---
title: "handleOutboundData(from:readBytesStartOffset:readBytes:)"
framework: networkextension
role: symbol
role_heading: Instance Method
path: "networkextension/nefilterdataprovider/handleoutbounddata(from:readbytesstartoffset:readbytes:)"
---

# handleOutboundData(from:readBytesStartOffset:readBytes:)

Make a filtering decision about a chunk of outbound data.

## Declaration

```swift
func handleOutboundData(from flow: NEFilterFlow, readBytesStartOffset offset: Int, readBytes: Data) -> NEFilterDataVerdict
```

## Parameters

- `flow`: An doc://com.apple.networkextension/documentation/NetworkExtension/NEFilterFlow object containing information about the flow.
- `offset`: An unsigned integer containing the offset of the data stored in readBytes. This offset is measured from the beginning of the flow’s outbound data.
- `readBytes`: An doc://com.apple.documentation/documentation/Foundation/NSData object containing the data to be filtered.

## Return Value

Return Value An NEFilterDataVerdict indicating how the system should handle the chunk of data and all subsequent outbound data for the flow.

## Discussion

Discussion NEFilterDataProvider subclasses must override this method.

## See Also

### Filtering network content

- [handleNewFlow(_:)](networkextension/nefilterdataprovider/handlenewflow(_:).md)
- [handleInboundData(from:readBytesStartOffset:readBytes:)](networkextension/nefilterdataprovider/handleinbounddata(from:readbytesstartoffset:readbytes:).md)
- [NEFilterDataAttribute](networkextension/nefilterdataattribute.md)
- [handleInboundDataComplete(for:)](networkextension/nefilterdataprovider/handleinbounddatacomplete(for:).md)
- [handleOutboundDataComplete(for:)](networkextension/nefilterdataprovider/handleoutbounddatacomplete(for:).md)