<!--
{
  "availability" : [
    "iOS: 9.0.0 -",
    "iPadOS: 9.0.0 -",
    "macCatalyst: 13.1.0 -",
    "macOS: 10.15.0 -",
    "visionOS: 1.0.0 -"
  ],
  "documentType" : "symbol",
  "framework" : "NetworkExtension",
  "identifier" : "/documentation/NetworkExtension/NEFilterFlow",
  "metadataVersion" : "0.1.0",
  "role" : "Class",
  "symbol" : {
    "kind" : "Class",
    "modules" : [
      "Network Extension"
    ],
    "preciseIdentifier" : "c:objc(cs)NEFilterFlow"
  },
  "title" : "NEFilterFlow"
}
-->

# NEFilterFlow

The abstract base class for types that represent flows of network data.

```
class NEFilterFlow
```

## Topics

### Inspecting flow properties

[`url`](/documentation/NetworkExtension/NEFilterFlow/url)

The flow’s HTTP URL.

[`identifier`](/documentation/NetworkExtension/NEFilterFlow/identifier)

The unique identifier of the flow.

[`direction`](/documentation/NetworkExtension/NEFilterFlow/direction)

The initial direction of the flow: incoming or outgoing.

[`NETrafficDirection`](/documentation/NetworkExtension/NETrafficDirection)

A type to represent the direction of network traffic.

[`NEFilterFlowBytesMax`](/documentation/NetworkExtension/NEFilterFlowBytesMax)

The maximum number of bytes to pass or peek for a flow.

### Source app identification

[`sourceAppUniqueIdentifier`](/documentation/NetworkExtension/NEFilterFlow/sourceAppUniqueIdentifier)

A byte string that uniquely identifies the binary for each build of the app that is the source of the flow.

[`sourceAppIdentifier`](/documentation/NetworkExtension/NEFilterFlow/sourceAppIdentifier)

A string containing the identifier of the source app of the flow.

[`sourceAppVersion`](/documentation/NetworkExtension/NEFilterFlow/sourceAppVersion)

The short version string of the app that is the source of the flow.

[`sourceAppAuditToken`](/documentation/NetworkExtension/NEFilterFlow/sourceAppAuditToken)

The audit token of the source application of the flow.

[`sourceProcessAuditToken`](/documentation/NetworkExtension/NEFilterFlow/sourceProcessAuditToken)

The audit token of the process that created the flow.


---

Copyright &copy; 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)