NSNetService is deprecated

[PedroRomanoBarbosa]

Since NSNetService is deprecated (https://developer.apple.com/documentation/foundation/netservice), do you have any plans to move it to the new alternative? Thanks!

[aschulz90]

The alternatives I know are:

• Swift only NWBrowser
• low level functions like nw_advertise_descriptor_create_bonjour_service

Since NWBrowser is Swift only, it can't be used from Kotlin side until Swift Interop is fully supported.

And for nw_advertise_descriptor_create_bonjour_service I haven't found any comprehensive documentation, except for this implementation, which looks like it would be a larger undertaking to re-implement in Kotlin.

So I currently have no plans to move away from NSNetService until at least Swift Interop is possible.

[PedroRomanoBarbosa]

The alternatives I know are:

• Swift only NWBrowser
• low level functions like nw_advertise_descriptor_create_bonjour_service

Since NWBrowser is Swift only, it can't be used from Kotlin side until Swift Interop is fully supported.

And for nw_advertise_descriptor_create_bonjour_service I haven't found any comprehensive documentation, except for this implementation, which looks like it would be a larger undertaking to re-implement in Kotlin.

So I currently have no plans to move away from NSNetService until at least Swift Interop is possible.

Thank you for the comprehensive response! I too tried the low level functions but gave up trying to use it. Hope they implement the swift interop as soon as possible!

[tim-alenus]

For a KMP project I am working on I created a version that uses NWBrowser (for discovery).
Because we are recreating an existing app which has a native Android and a native iOS implementation and where the native iOS implementation uses NWBrowser, I did not want to introduce a deprecated dependency by using NSNetService.

You can find my version that uses NWBrowser for discovery here: https://github.com/tim-alenus/dns-sd-kt/tree/feature/nw-browser
Once I tested more as part of the project I am working and i am feeling more confident with the implementation I'll submit a pull request.

[aschulz90]

I checked out your implementation and it seems promising! Thank you.
But only the discovery seems to be working and not the resolve (tested on both simulator and real device):

main Branch:

feature/nw-browser Branch:

The allow local network access permission was granted.

The log shows some error regarding Failed to attach socket protocol:

/Users/andreas/Library/Caches/Google/AndroidStudio2025.2.2/DerivedData/iosApp-etruxalrmkzpkjfkuvwtcmmpixyq/Build/Products/Debug-iphonesimulator/NsdKt.app
2026-01-18 14:31:51.590097+0100 NsdKt[55549:780013] [General] Failed to send CA Event for app launch measurements for ca_event_type: 0 event_name: com.apple.app_launch_measurement.FirstFramePresentationMetric
2026-01-18 14:31:51.632645+0100 NsdKt[55549:780007] [General] Failed to send CA Event for app launch measurements for ca_event_type: 1 event_name: com.apple.app_launch_measurement.ExtendedLaunchMetrics
2026-01-18 14:31:53.913774+0100 NsdKt[55549:780008] [listener] nw_listener_start_block_invoke [L1] Started without setting either new connection handler or new connection group handler
2026-01-18 14:31:53.913931+0100 NsdKt[55549:780013] NWBrowser permission state changed: 1
2026-01-18 14:31:53.935585+0100 NsdKt[55549:780013] NWBrowser permission state changed: 1
2026-01-18 14:31:53.952629+0100 NsdKt[55549:780008] NWBrowser found service: android-587fc07a-590d-43b3-afee-7069e573ca5e of type _example._tcp in domain local.
2026-01-18 14:31:53.977635+0100 NsdKt[55549:780013] [] nw_endpoint_handler_set_protocol_instance called with null protocol_parameters
2026-01-18 14:31:53.977748+0100 NsdKt[55549:780013] [] nw_protocol_options_get_log_id_str called with null options
2026-01-18 14:31:53.977808+0100 NsdKt[55549:780013] [] nw_protocol_options_get_log_id_num called with null options
2026-01-18 14:31:53.977868+0100 NsdKt[55549:780013] [] nw_protocol_options_is_udp called with null options
2026-01-18 14:31:53.978151+0100 NsdKt[55549:780013] [] nw_protocol_options_is_quic called with null options
2026-01-18 14:31:53.978200+0100 NsdKt[55549:780013] [] nw_protocol_options_is_tcp called with null options
2026-01-18 14:31:53.978285+0100 NsdKt[55549:780013] [connection] nw_socket_initialize_socket  Data mode 0 unrecognized
2026-01-18 14:31:53.978486+0100 NsdKt[55549:780013] [connection] nw_socket_add_input_handler  Failed to initialize socket
2026-01-18 14:31:53.978516+0100 NsdKt[55549:780013] [connection] nw_endpoint_flow_attach_protocols [C1.1.1.1 fe80::b46b:78ff:fe20:9703%en0.8080 in_progress socket-flow (satisfied (Path is satisfied), interface: en0[802.11], uses wifi, LQM: unknown)] Failed to attach socket protocol
2026-01-18 14:31:53.978558+0100 NsdKt[55549:780013] [connection] nw_endpoint_flow_failed_with_error [C1.1.1.1 fe80::b46b:78ff:fe20:9703%en0.8080 in_progress socket-flow (satisfied (Path is satisfied), interface: en0[802.11], uses wifi, LQM: unknown)] already failing, returning
2026-01-18 14:31:53.978943+0100 NsdKt[55549:780013] [] nw_endpoint_handler_set_protocol_instance called with null protocol_parameters, backtrace limit exceeded
2026-01-18 14:31:53.978979+0100 NsdKt[55549:780013] [] nw_protocol_options_get_log_id_str called with null options, backtrace limit exceeded
2026-01-18 14:31:53.979032+0100 NsdKt[55549:780013] [] nw_protocol_options_get_log_id_num called with null options, backtrace limit exceeded
2026-01-18 14:31:53.979058+0100 NsdKt[55549:780013] [] nw_protocol_options_is_udp called with null options, backtrace limit exceeded
2026-01-18 14:31:53.979081+0100 NsdKt[55549:780013] [] nw_protocol_options_is_quic called with null options, backtrace limit exceeded
2026-01-18 14:31:53.979158+0100 NsdKt[55549:780013] [] nw_protocol_options_is_tcp called with null options, backtrace limit exceeded
2026-01-18 14:31:53.979178+0100 NsdKt[55549:780013] [connection] nw_socket_initialize_socket  Data mode 0 unrecognized
2026-01-18 14:31:53.979204+0100 NsdKt[55549:780013] [connection] nw_socket_add_input_handler  Failed to initialize socket
2026-01-18 14:31:53.979235+0100 NsdKt[55549:780013] [connection] nw_endpoint_flow_attach_protocols [C1.1.1.2 2003:e5:a737:7800:b46b:78ff:fe20:9703.8080 in_progress socket-flow (satisfied (Path is satisfied), interface: en0[802.11], uses wifi, LQM: unknown)] Failed to attach socket protocol
2026-01-18 14:31:53.979318+0100 NsdKt[55549:780013] [connection] nw_endpoint_flow_failed_with_error [C1.1.1.2 2003:e5:a737:7800:b46b:78ff:fe20:9703.8080 in_progress socket-flow (satisfied (Path is satisfied), interface: en0[802.11], uses wifi, LQM: unknown)] already failing, returning
2026-01-18 14:31:53.979614+0100 NsdKt[55549:780013] [] nw_endpoint_handler_set_protocol_instance called with null protocol_parameters, backtrace limit exceeded
2026-01-18 14:31:53.979636+0100 NsdKt[55549:780013] [] nw_protocol_options_get_log_id_str called with null options, backtrace limit exceeded
2026-01-18 14:31:53.979659+0100 NsdKt[55549:780013] [] nw_protocol_options_get_log_id_num called with null options, backtrace limit exceeded
2026-01-18 14:31:53.979681+0100 NsdKt[55549:780013] [] nw_protocol_options_is_udp called with null options, backtrace limit exceeded
2026-01-18 14:31:53.979702+0100 NsdKt[55549:780013] [] nw_protocol_options_is_quic called with null options, backtrace limit exceeded
2026-01-18 14:31:53.979725+0100 NsdKt[55549:780013] [] nw_protocol_options_is_tcp called with null options, backtrace limit exceeded
2026-01-18 14:31:53.979750+0100 NsdKt[55549:780013] [connection] nw_socket_initialize_socket  Data mode 0 unrecognized
2026-01-18 14:31:53.979773+0100 NsdKt[55549:780013] [connection] nw_socket_add_input_handler  Failed to initialize socket
2026-01-18 14:31:53.979792+0100 NsdKt[55549:780013] [connection] nw_endpoint_flow_attach_protocols [C1.1.1.3 192.168.178.44:8080 in_progress socket-flow (satisfied (Path is satisfied), interface: en0[802.11], uses wifi, LQM: unknown)] Failed to attach socket protocol
2026-01-18 14:31:53.979819+0100 NsdKt[55549:780013] [connection] nw_endpoint_flow_failed_with_error [C1.1.1.3 192.168.178.44:8080 in_progress socket-flow (satisfied (Path is satisfied), interface: en0[802.11], uses wifi, LQM: unknown)] already failing, returning
2026-01-18 14:31:53.980027+0100 NsdKt[55549:780013] [] nw_endpoint_handler_set_protocol_instance called with null protocol_parameters, backtrace limit exceeded
2026-01-18 14:31:53.980052+0100 NsdKt[55549:780013] [] nw_protocol_options_get_log_id_str called with null options, backtrace limit exceeded
2026-01-18 14:31:53.980086+0100 NsdKt[55549:780013] [] nw_protocol_options_get_log_id_num called with null options, backtrace limit exceeded
2026-01-18 14:31:53.980104+0100 NsdKt[55549:780013] [] nw_protocol_options_is_udp called with null options, backtrace limit exceeded
2026-01-18 14:31:53.980123+0100 NsdKt[55549:780013] [] nw_protocol_options_is_quic called with null options, backtrace limit exceeded
2026-01-18 14:31:53.980146+0100 NsdKt[55549:780013] [] nw_protocol_options_is_tcp called with null options, backtrace limit exceeded
2026-01-18 14:31:53.980174+0100 NsdKt[55549:780013] [connection] nw_socket_initialize_socket  Data mode 0 unrecognized
2026-01-18 14:31:53.980195+0100 NsdKt[55549:780013] [connection] nw_socket_add_input_handler  Failed to initialize socket
2026-01-18 14:31:53.980212+0100 NsdKt[55549:780013] [connection] nw_endpoint_flow_attach_protocols [C1.1.1.4 fd7e:5f1e:3adc:0:b46b:78ff:fe20:9703.8080 in_progress socket-flow (satisfied (Path is satisfied), interface: en0[802.11], uses wifi, LQM: unknown)] Failed to attach socket protocol
2026-01-18 14:31:53.980523+0100 NsdKt[55549:780013] [connection] nw_endpoint_flow_failed_with_error [C1.1.1.4 fd7e:5f1e:3adc:0:b46b:78ff:fe20:9703.8080 in_progress socket-flow (satisfied (Path is satisfied), interface: en0[802.11], uses wifi, LQM: unknown)] already failing, returning

[tim-alenus]

Hi Andreas, thanks for testing. The project i am using this in is still in active development. I'll have a look the issue with the resolve. Once i am confident with the implementation and internal testing has succeeded i'll create a pull request here.

[tim-alenus]

@aschulz90 i fixed the resolve on my fork.