feat: emit $is_server property on captured events

[turnipdabeets]

Adds $is_server: true to every event captured by this SDK so PostHog ingestion can identify server-side events.

[github-actions]

posthog-dotnet Compliance Report

Date: 2026-06-03 18:04:21 UTC
Duration: 632ms

⚠️ Some Tests Failed

2/16 tests passed, 14 failed

---

Feature_Flags Tests

⚠️ 2/16 tests passed, 14 failed

View Details

Test	Status	Duration
Request Payload.Request With Person Properties Device Id	❌	44ms
Request Payload.Flags Request Uses V2 Query Param	❌	22ms
Request Payload.Flags Request Hits Flags Path Not Decide	❌	6ms
Request Payload.Flags Request Omits Authorization Header	❌	5ms
Request Payload.Token In Flags Body Matches Init	❌	5ms
Request Payload.Groups Round Trip	❌	5ms
Request Payload.Groups Default To Empty Object	❌	5ms
Request Payload.Person Properties Distinct Id Auto Populated When Caller Omits It	❌	4ms
Request Payload.Disable Geoip False Propagates As Geoip Disable False	❌	6ms
Request Payload.Disable Geoip Omitted Defaults To False	❌	5ms
Request Payload.Flag Keys To Evaluate Contains Only Requested Key	❌	6ms
Request Lifecycle.No Flags Request On Init Alone	✅	4ms
Request Lifecycle.No Flags Request On Normal Capture	✅	184ms
Request Lifecycle.Two Flag Calls Produce Two Remote Requests	❌	6ms
Request Lifecycle.Mock Response Value Is Returned To Caller	❌	5ms
Side Effect Events.Get Feature Flag Captures Feature Flag Called Event	❌	5ms

Failures

request_payload.request_with_person_properties_device_id

404, message='Not Found', url='http://sdk-adapter:8080/get_feature_flag'

request_payload.flags_request_uses_v2_query_param

404, message='Not Found', url='http://sdk-adapter:8080/get_feature_flag'

request_payload.flags_request_hits_flags_path_not_decide

404, message='Not Found', url='http://sdk-adapter:8080/get_feature_flag'

request_payload.flags_request_omits_authorization_header

404, message='Not Found', url='http://sdk-adapter:8080/get_feature_flag'

request_payload.token_in_flags_body_matches_init

404, message='Not Found', url='http://sdk-adapter:8080/get_feature_flag'

request_payload.groups_round_trip

404, message='Not Found', url='http://sdk-adapter:8080/get_feature_flag'

request_payload.groups_default_to_empty_object

404, message='Not Found', url='http://sdk-adapter:8080/get_feature_flag'

request_payload.person_properties_distinct_id_auto_populated_when_caller_omits_it

404, message='Not Found', url='http://sdk-adapter:8080/get_feature_flag'

request_payload.disable_geoip_false_propagates_as_geoip_disable_false

404, message='Not Found', url='http://sdk-adapter:8080/get_feature_flag'

request_payload.disable_geoip_omitted_defaults_to_false

404, message='Not Found', url='http://sdk-adapter:8080/get_feature_flag'

request_payload.flag_keys_to_evaluate_contains_only_requested_key

404, message='Not Found', url='http://sdk-adapter:8080/get_feature_flag'

request_lifecycle.two_flag_calls_produce_two_remote_requests

404, message='Not Found', url='http://sdk-adapter:8080/get_feature_flag'

request_lifecycle.mock_response_value_is_returned_to_caller

404, message='Not Found', url='http://sdk-adapter:8080/get_feature_flag'

side_effect_events.get_feature_flag_captures_feature_flag_called_event

404, message='Not Found', url='http://sdk-adapter:8080/get_feature_flag'

[greptile-apps]

_{Reviews (1): Last reviewed commit: "feat: emit $is_server property on captur..." | Re-trigger Greptile}

[dustinbyrne]

this looks like a public API - do we need this addition?

We could write $is_server in PostHogClient.CaptureCore after creating the captured event. That'd also allow us to avoid changing ExceptionPropertiesBuilder, as exception events would also flow through CaptureCore.

I think it's worth it because it limits the public API scope creep and keeps config.IsServer as the single authority

[turnipdabeets]

updated