send_webhook fixes

server/reflector/hatchet/workflows/daily_multitrack_pipeline.py

@@ -1,9 +1,12 @@
 """
-Hatchet main workflow: DiarizationPipeline
+Hatchet main workflow: DailyMultitrackPipeline
 
-Multitrack diarization pipeline for Daily.co recordings.
+Multitrack processing pipeline for Daily.co recordings.
 Orchestrates the full processing flow from recording metadata to final transcript.
 
+Daily.co recordings don't require ML diarization - speaker identification comes from
+track index (each participant's audio is a separate track).
+
 Note: This file uses deferred imports (inside functions/tasks) intentionally.
 Hatchet workers run in forked processes; fresh imports per task ensure DB connections
 are not shared across forks, avoiding connection pooling issues.
@@ -93,7 +96,7 @@ from reflector.zulip import post_transcript_notification
 
 
 class PipelineInput(BaseModel):
-    """Input to trigger the diarization pipeline."""
+    """Input to trigger the Daily.co multitrack pipeline."""
 
     recording_id: NonEmptyString
     tracks: list[dict]  # List of {"s3_key": str}
@@ -104,8 +107,8 @@ class PipelineInput(BaseModel):
 
 hatchet = HatchetClientManager.get_client()
 
-diarization_pipeline = hatchet.workflow(
-    name="DiarizationPipeline", input_validator=PipelineInput
+daily_multitrack_pipeline = hatchet.workflow(
+    name="DailyMultitrackPipeline", input_validator=PipelineInput
 )
 
 
@@ -191,7 +194,7 @@ def with_error_handling(step_name: str, set_error_status: bool = True) -> Callab
     return decorator
 
 
-@diarization_pipeline.task(
+@daily_multitrack_pipeline.task(
     execution_timeout=timedelta(seconds=TIMEOUT_SHORT), retries=3
 )
 @with_error_handling("get_recording")
@@ -244,7 +247,7 @@ async def get_recording(input: PipelineInput, ctx: Context) -> RecordingResult:
     )
 
 
-@diarization_pipeline.task(
+@daily_multitrack_pipeline.task(
     parents=[get_recording],
     execution_timeout=timedelta(seconds=TIMEOUT_SHORT),
     retries=3,
@@ -335,7 +338,7 @@ async def get_participants(input: PipelineInput, ctx: Context) -> ParticipantsRe
     )
 
 
-@diarization_pipeline.task(
+@daily_multitrack_pipeline.task(
     parents=[get_participants],
     execution_timeout=timedelta(seconds=TIMEOUT_HEAVY),
     retries=3,
@@ -404,7 +407,7 @@ async def process_tracks(input: PipelineInput, ctx: Context) -> ProcessTracksRes
     )
 
 
-@diarization_pipeline.task(
+@daily_multitrack_pipeline.task(
     parents=[process_tracks],
     execution_timeout=timedelta(seconds=TIMEOUT_AUDIO),
     retries=3,
@@ -487,7 +490,7 @@ async def mixdown_tracks(input: PipelineInput, ctx: Context) -> MixdownResult:
     )
 
 
-@diarization_pipeline.task(
+@daily_multitrack_pipeline.task(
     parents=[mixdown_tracks],
     execution_timeout=timedelta(seconds=TIMEOUT_MEDIUM),
     retries=3,
@@ -555,7 +558,7 @@ async def generate_waveform(input: PipelineInput, ctx: Context) -> WaveformResul
     return WaveformResult(waveform_generated=True)
 
 
-@diarization_pipeline.task(
+@daily_multitrack_pipeline.task(
     parents=[mixdown_tracks],
     execution_timeout=timedelta(seconds=TIMEOUT_HEAVY),
     retries=3,
@@ -658,7 +661,7 @@ async def detect_topics(input: PipelineInput, ctx: Context) -> TopicsResult:
     return TopicsResult(topics=topics_list)
 
 
-@diarization_pipeline.task(
+@daily_multitrack_pipeline.task(
     parents=[detect_topics],
     execution_timeout=timedelta(seconds=TIMEOUT_HEAVY),
     retries=3,
@@ -721,7 +724,7 @@ async def generate_title(input: PipelineInput, ctx: Context) -> TitleResult:
     return TitleResult(title=title_result)
 
 
-@diarization_pipeline.task(
+@daily_multitrack_pipeline.task(
     parents=[detect_topics],
     execution_timeout=timedelta(seconds=TIMEOUT_MEDIUM),
     retries=3,
@@ -802,7 +805,7 @@ async def extract_subjects(input: PipelineInput, ctx: Context) -> SubjectsResult
     )
 
 
-@diarization_pipeline.task(
+@daily_multitrack_pipeline.task(
     parents=[extract_subjects],
     execution_timeout=timedelta(seconds=TIMEOUT_HEAVY),
     retries=3,
@@ -844,7 +847,7 @@ async def process_subjects(input: PipelineInput, ctx: Context) -> ProcessSubject
     return ProcessSubjectsResult(subject_summaries=subject_summaries)
 
 
-@diarization_pipeline.task(
+@daily_multitrack_pipeline.task(
     parents=[process_subjects],
     execution_timeout=timedelta(seconds=TIMEOUT_MEDIUM),
     retries=3,
@@ -938,7 +941,7 @@ async def generate_recap(input: PipelineInput, ctx: Context) -> RecapResult:
     return RecapResult(short_summary=short_summary, long_summary=long_summary)
 
 
-@diarization_pipeline.task(
+@daily_multitrack_pipeline.task(
     parents=[extract_subjects],
     execution_timeout=timedelta(seconds=TIMEOUT_LONG),
     retries=3,
@@ -1009,7 +1012,7 @@ async def identify_action_items(
     return ActionItemsResult(action_items=action_items_dict)
 
 
-@diarization_pipeline.task(
+@daily_multitrack_pipeline.task(
     parents=[generate_waveform, generate_title, generate_recap, identify_action_items],
     execution_timeout=timedelta(seconds=TIMEOUT_SHORT),
     retries=3,
@@ -1094,7 +1097,7 @@ async def finalize(input: PipelineInput, ctx: Context) -> FinalizeResult:
     return FinalizeResult(status="COMPLETED")
 
 
-@diarization_pipeline.task(
+@daily_multitrack_pipeline.task(
     parents=[finalize], execution_timeout=timedelta(seconds=TIMEOUT_SHORT), retries=3
 )
 @with_error_handling("cleanup_consent", set_error_status=False)
@@ -1194,7 +1197,7 @@ async def cleanup_consent(input: PipelineInput, ctx: Context) -> ConsentResult:
     return ConsentResult()
 
 
-@diarization_pipeline.task(
+@daily_multitrack_pipeline.task(
     parents=[cleanup_consent],
     execution_timeout=timedelta(seconds=TIMEOUT_SHORT),
     retries=5,
@@ -1221,14 +1224,14 @@ async def post_zulip(input: PipelineInput, ctx: Context) -> ZulipResult:
     return ZulipResult(zulip_message_id=message_id)
 
 
-@diarization_pipeline.task(
+@daily_multitrack_pipeline.task(
     parents=[post_zulip],
     execution_timeout=timedelta(seconds=TIMEOUT_MEDIUM),
     retries=30,
 )
 @with_error_handling("send_webhook", set_error_status=False)
 async def send_webhook(input: PipelineInput, ctx: Context) -> WebhookResult:
-    """Send completion webhook to external service."""
+    """Send completion webhook to external service with full payload and HMAC signature."""
     ctx.log(f"send_webhook: transcript_id={input.transcript_id}")
 
     if not input.room_id:
@@ -1237,27 +1240,39 @@ async def send_webhook(input: PipelineInput, ctx: Context) -> WebhookResult:
 
     async with fresh_db_connection():
         from reflector.db.rooms import rooms_controller  # noqa: PLC0415
-        from reflector.db.transcripts import transcripts_controller  # noqa: PLC0415
+        from reflector.utils.webhook import (  # noqa: PLC0415
+            build_transcript_webhook_payload,
+            send_webhook_request,
+        )
 
         room = await rooms_controller.get_by_id(input.room_id)
-        transcript = await transcripts_controller.get_by_id(input.transcript_id)
+        if not room or not room.webhook_url:
+            ctx.log("send_webhook skipped (no webhook_url configured)")
+            return WebhookResult(webhook_sent=False, skipped=True)
 
-        if room and room.webhook_url and transcript:
-            webhook_payload = {
-                "event": "transcript.completed",
-                "transcript_id": input.transcript_id,
-                "title": transcript.title,
-                "duration": transcript.duration,
-            }
+        payload = await build_transcript_webhook_payload(
+            transcript_id=input.transcript_id,
+            room_id=input.room_id,
+        )
 
-            async with httpx.AsyncClient() as client:
-                response = await client.post(
-                    room.webhook_url, json=webhook_payload, timeout=30
-                )
-                response.raise_for_status()
+        if not payload:
+            ctx.log("send_webhook skipped (could not build payload)")
+            return WebhookResult(webhook_sent=False, skipped=True)
 
-            ctx.log(f"send_webhook complete: status_code={response.status_code}")
+        ctx.log(
+            f"send_webhook: sending to {room.webhook_url} "
+            f"(topics={len(payload.transcript.topics)}, "
+            f"participants={len(payload.transcript.participants)})"
+        )
 
-            return WebhookResult(webhook_sent=True, response_code=response.status_code)
+        response = await send_webhook_request(
+            url=room.webhook_url,
+            payload=payload,
+            event_type="transcript.completed",
+            webhook_secret=room.webhook_secret,
+            timeout=30.0,
+        )
 
-    return WebhookResult(webhook_sent=False, skipped=True)
+        ctx.log(f"send_webhook complete: status_code={response.status_code}")
+
+        return WebhookResult(webhook_sent=True, response_code=response.status_code)

server/reflector/hatchet/workflows/track_processing.py

@@ -4,10 +4,10 @@ Hatchet child workflow: TrackProcessing
 Handles individual audio track processing: padding and transcription.
 Spawned dynamically by the main diarization pipeline for each track.
 
-Architecture note: This is a separate workflow (not inline tasks in DiarizationPipeline)
+Architecture note: This is a separate workflow (not inline tasks in DailyMultitrackPipeline)
 because Hatchet workflow DAGs are defined statically, but the number of tracks varies
 at runtime. Child workflow spawning via `aio_run()` + `asyncio.gather()` is the
-standard pattern for dynamic fan-out. See `process_tracks` in diarization_pipeline.py.
+standard pattern for dynamic fan-out. See `process_tracks` in daily_multitrack_pipeline.py.
 
 Note: This file uses deferred imports (inside tasks) intentionally.
 Hatchet workers run in forked processes; fresh imports per task ensure

server/reflector/utils/audio_waveform.py

@@ -3,8 +3,12 @@ from pathlib import Path
 import av
 import numpy as np
 
+from reflector.utils.audio_constants import WAVEFORM_SEGMENTS
 
-def get_audio_waveform(path: Path | str, segments_count: int = 256) -> list[int]:
+
+def get_audio_waveform(
+    path: Path | str, segments_count: int = WAVEFORM_SEGMENTS
+) -> list[int]:
     if isinstance(path, Path):
         path = path.as_posix()
 
@@ -70,7 +74,7 @@ if __name__ == "__main__":
 
     parser = argparse.ArgumentParser()
     parser.add_argument("path", type=Path)
-    parser.add_argument("--segments-count", type=int, default=256)
+    parser.add_argument("--segments-count", type=int, default=WAVEFORM_SEGMENTS)
     args = parser.parse_args()
 
     print(get_audio_waveform(args.path, args.segments_count))

server/reflector/utils/webhook.py

@@ -0,0 +1,224 @@
+"""Webhook utilities.
+
+Shared webhook functionality for both Hatchet and Celery pipelines.
+"""
+
+import hashlib
+import hmac
+import uuid
+from datetime import datetime, timezone
+
+import httpx
+from pydantic import BaseModel
+
+from reflector.logger import logger
+from reflector.settings import settings
+from reflector.utils.webhook_outgoing_models import (
+    WebhookCalendarEventPayload,
+    WebhookParticipantPayload,
+    WebhookPayload,
+    WebhookRoomPayload,
+    WebhookTestPayload,
+    WebhookTopicPayload,
+    WebhookTranscriptPayload,
+)
+
+__all__ = [
+    "WebhookCalendarEventPayload",
+    "WebhookParticipantPayload",
+    "WebhookPayload",
+    "WebhookRoomPayload",
+    "WebhookTestPayload",
+    "WebhookTopicPayload",
+    "WebhookTranscriptPayload",
+    "_serialize_payload",
+    "build_transcript_webhook_payload",
+    "build_test_webhook_payload",
+    "build_webhook_headers",
+    "generate_webhook_signature",
+    "send_webhook_request",
+]
+
+
+def _serialize_payload(payload: BaseModel) -> bytes:
+    """Serialize Pydantic model to compact JSON bytes."""
+    return payload.model_dump_json(by_alias=True, exclude_none=False).encode("utf-8")
+
+
+def generate_webhook_signature(payload: bytes, secret: str, timestamp: str) -> str:
+    """Generate HMAC-SHA256 signature for webhook payload."""
+    signed_payload = f"{timestamp}.{payload.decode('utf-8')}"
+    hmac_obj = hmac.new(
+        secret.encode("utf-8"),
+        signed_payload.encode("utf-8"),
+        hashlib.sha256,
+    )
+    return hmac_obj.hexdigest()
+
+
+def build_webhook_headers(
+    event_type: str,
+    payload_bytes: bytes,
+    webhook_secret: str | None = None,
+    retry_count: int = 0,
+) -> dict[str, str]:
+    headers = {
+        "Content-Type": "application/json",
+        "User-Agent": "Reflector-Webhook/1.0",
+        "X-Webhook-Event": event_type,
+        "X-Webhook-Retry": str(retry_count),
+    }
+
+    if webhook_secret:
+        timestamp = str(int(datetime.now(timezone.utc).timestamp()))
+        signature = generate_webhook_signature(payload_bytes, webhook_secret, timestamp)
+        headers["X-Webhook-Signature"] = f"t={timestamp},v1={signature}"
+
+    return headers
+
+
+async def send_webhook_request(
+    url: str,
+    payload: BaseModel,
+    event_type: str,
+    webhook_secret: str | None = None,
+    retry_count: int = 0,
+    timeout: float = 30.0,
+) -> httpx.Response:
+    """Send webhook request with proper headers and signature.
+
+    Raises:
+        httpx.HTTPStatusError: On non-2xx response
+        httpx.ConnectError: On connection failure
+        httpx.TimeoutException: On timeout
+    """
+    payload_bytes = _serialize_payload(payload)
+
+    headers = build_webhook_headers(
+        event_type=event_type,
+        payload_bytes=payload_bytes,
+        webhook_secret=webhook_secret,
+        retry_count=retry_count,
+    )
+
+    async with httpx.AsyncClient(timeout=timeout) as client:
+        response = await client.post(url, content=payload_bytes, headers=headers)
+        response.raise_for_status()
+        return response
+
+
+async def build_transcript_webhook_payload(
+    transcript_id: str,
+    room_id: str,
+) -> WebhookPayload | None:
+    """Build webhook payload by fetching transcript and room data from database."""
+    # Inline imports required: this utils module would create circular imports
+    # if db modules were imported at top level (utils -> db -> ... -> utils).
+    # This pattern is consistent with Hatchet task files.
+    from reflector.db.calendar_events import calendar_events_controller  # noqa: PLC0415
+    from reflector.db.meetings import meetings_controller  # noqa: PLC0415
+    from reflector.db.rooms import rooms_controller  # noqa: PLC0415
+    from reflector.db.transcripts import transcripts_controller  # noqa: PLC0415
+    from reflector.utils.webvtt import topics_to_webvtt  # noqa: PLC0415
+
+    transcript = await transcripts_controller.get_by_id(transcript_id)
+    if not transcript:
+        return None
+
+    room = await rooms_controller.get_by_id(room_id)
+    if not room:
+        return None
+
+    topics_data = [
+        WebhookTopicPayload(
+            title=topic.title,
+            summary=topic.summary,
+            timestamp=topic.timestamp,
+            duration=topic.duration,
+            webvtt=topics_to_webvtt([topic]) if topic.words else "",
+        )
+        for topic in (transcript.topics or [])
+    ]
+
+    participants_data = [
+        WebhookParticipantPayload(id=p.id, name=p.name, speaker=p.speaker)
+        for p in (transcript.participants or [])
+    ]
+
+    calendar_event_data: WebhookCalendarEventPayload | None = None
+    try:
+        if transcript.meeting_id:
+            meeting = await meetings_controller.get_by_id(transcript.meeting_id)
+            if meeting and meeting.calendar_event_id:
+                calendar_event = await calendar_events_controller.get_by_id(
+                    meeting.calendar_event_id
+                )
+                if calendar_event:
+                    calendar_event_data = WebhookCalendarEventPayload(
+                        id=calendar_event.id,
+                        ics_uid=calendar_event.ics_uid,
+                        title=calendar_event.title,
+                        start_time=calendar_event.start_time,
+                        end_time=calendar_event.end_time,
+                        description=calendar_event.description or None,
+                        location=calendar_event.location or None,
+                        attendees=calendar_event.attendees or None,
+                    )
+    except Exception as e:
+        logger.warning(
+            "Failed to fetch calendar event for webhook",
+            transcript_id=transcript_id,
+            meeting_id=transcript.meeting_id,
+            error=str(e),
+        )
+
+    frontend_url = f"{settings.UI_BASE_URL}/transcripts/{transcript.id}"
+
+    return WebhookPayload(
+        event="transcript.completed",
+        event_id=uuid.uuid4().hex,
+        timestamp=datetime.now(timezone.utc),
+        transcript=WebhookTranscriptPayload(
+            id=transcript.id,
+            room_id=transcript.room_id,
+            created_at=transcript.created_at,
+            duration=transcript.duration,
+            title=transcript.title,
+            short_summary=transcript.short_summary,
+            long_summary=transcript.long_summary,
+            webvtt=transcript.webvtt,
+            topics=topics_data,
+            participants=participants_data,
+            source_language=transcript.source_language,
+            target_language=transcript.target_language,
+            status=transcript.status,
+            frontend_url=frontend_url,
+            action_items=transcript.action_items,
+        ),
+        room=WebhookRoomPayload(
+            id=room.id,
+            name=room.name,
+        ),
+        calendar_event=calendar_event_data,
+    )
+
+
+async def build_test_webhook_payload(room_id: str) -> WebhookTestPayload | None:
+    """Build test webhook payload."""
+    # Inline import: avoid circular dependency (utils -> db -> utils)
+    from reflector.db.rooms import rooms_controller  # noqa: PLC0415
+
+    room = await rooms_controller.get_by_id(room_id)
+    if not room:
+        return None
+
+    return WebhookTestPayload(
+        event="test",
+        event_id=uuid.uuid4().hex,
+        timestamp=datetime.now(timezone.utc),
+        message="This is a test webhook from Reflector",
+        room=WebhookRoomPayload(
+            id=room.id,
+            name=room.name,
+        ),
+    )

server/reflector/utils/webhook_outgoing_models.py

@@ -0,0 +1,80 @@
+"""Pydantic models for outgoing webhook payloads.
+
+These models define the structure of webhook payloads sent by Reflector
+to external services when transcript processing completes.
+"""
+
+from datetime import datetime
+from typing import Literal
+
+from pydantic import BaseModel
+
+from reflector.utils.string import NonEmptyString
+
+WebhookTranscriptEventType = Literal["transcript.completed"]
+WebhookTestEventType = Literal["test"]
+
+
+class WebhookTopicPayload(BaseModel):
+    title: NonEmptyString
+    summary: NonEmptyString
+    timestamp: float
+    duration: float | None
+    webvtt: str  # can be empty when no words
+
+
+class WebhookParticipantPayload(BaseModel):
+    id: NonEmptyString
+    name: str | None
+    speaker: int | None
+
+
+class WebhookRoomPayload(BaseModel):
+    id: NonEmptyString
+    name: NonEmptyString
+
+
+class WebhookCalendarEventPayload(BaseModel):
+    id: NonEmptyString
+    ics_uid: str | None = None
+    title: str | None = None
+    start_time: datetime | None = None
+    end_time: datetime | None = None
+    description: str | None = None
+    location: str | None = None
+    attendees: list[str] | None = None
+
+
+class WebhookTranscriptPayload(BaseModel):
+    id: NonEmptyString
+    room_id: NonEmptyString | None
+    created_at: datetime
+    duration: float | None
+    title: str | None
+    short_summary: str | None
+    long_summary: str | None
+    webvtt: str | None
+    topics: list[WebhookTopicPayload]
+    participants: list[WebhookParticipantPayload]
+    source_language: NonEmptyString
+    target_language: NonEmptyString
+    status: NonEmptyString
+    frontend_url: NonEmptyString
+    action_items: dict | None
+
+
+class WebhookPayload(BaseModel):
+    event: WebhookTranscriptEventType
+    event_id: NonEmptyString
+    timestamp: datetime
+    transcript: WebhookTranscriptPayload
+    room: WebhookRoomPayload
+    calendar_event: WebhookCalendarEventPayload | None = None
+
+
+class WebhookTestPayload(BaseModel):
+    event: WebhookTestEventType
+    event_id: NonEmptyString
+    timestamp: datetime
+    message: NonEmptyString
+    room: WebhookRoomPayload

server/reflector/worker/process.py

@@ -300,7 +300,7 @@ async def _process_multitrack_recording_inner(
 
     if use_hatchet:
         workflow_id = await HatchetClientManager.start_workflow(
-            workflow_name="DiarizationPipeline",
+            workflow_name="DailyMultitrackPipeline",
             input_data={
                 "recording_id": recording_id,
                 "tracks": [{"s3_key": k} for k in filter_cam_audio_tracks(track_keys)],
@@ -848,7 +848,7 @@ async def reprocess_failed_daily_recordings():
                     continue
 
                 workflow_id = await HatchetClientManager.start_workflow(
-                    workflow_name="DiarizationPipeline",
+                    workflow_name="DailyMultitrackPipeline",
                     input_data={
                         "recording_id": recording.id,
                         "tracks": [

server/reflector/worker/webhook.py

@@ -1,8 +1,5 @@
 """Webhook task for sending transcript notifications."""
 
-import hashlib
-import hmac
-import json
 import uuid
 from datetime import datetime, timezone
 
@@ -11,28 +8,20 @@ import structlog
 from celery import shared_task
 from celery.utils.log import get_task_logger
 
-from reflector.db.calendar_events import calendar_events_controller
-from reflector.db.meetings import meetings_controller
 from reflector.db.rooms import rooms_controller
-from reflector.db.transcripts import transcripts_controller
 from reflector.pipelines.main_live_pipeline import asynctask
-from reflector.settings import settings
-from reflector.utils.webvtt import topics_to_webvtt
+from reflector.utils.webhook import (
+    WebhookRoomPayload,
+    WebhookTestPayload,
+    _serialize_payload,
+    build_transcript_webhook_payload,
+    build_webhook_headers,
+    send_webhook_request,
+)
 
 logger = structlog.wrap_logger(get_task_logger(__name__))
 
 
-def generate_webhook_signature(payload: bytes, secret: str, timestamp: str) -> str:
-    """Generate HMAC signature for webhook payload."""
-    signed_payload = f"{timestamp}.{payload.decode('utf-8')}"
-    hmac_obj = hmac.new(
-        secret.encode("utf-8"),
-        signed_payload.encode("utf-8"),
-        hashlib.sha256,
-    )
-    return hmac_obj.hexdigest()
-
-
 @shared_task(
     bind=True,
     max_retries=30,
@@ -47,6 +36,11 @@ async def send_transcript_webhook(
     room_id: str,
     event_id: str,
 ):
+    """Send webhook notification for completed transcript.
+
+    Uses shared Pydantic models and signature generation from utils/webhook.py
+    to ensure consistency with Hatchet pipeline.
+    """
     log = logger.bind(
         transcript_id=transcript_id,
         room_id=room_id,
@@ -54,12 +48,6 @@ async def send_transcript_webhook(
     )
 
     try:
-        # Fetch transcript and room
-        transcript = await transcripts_controller.get_by_id(transcript_id)
-        if not transcript:
-            log.error("Transcript not found, skipping webhook")
-            return
-
         room = await rooms_controller.get_by_id(room_id)
         if not room:
             log.error("Room not found, skipping webhook")
@@ -69,135 +57,37 @@ async def send_transcript_webhook(
             log.info("No webhook URL configured for room, skipping")
             return
 
-        # Generate WebVTT content from topics
-        topics_data = []
+        # Build payload using shared function
+        payload = await build_transcript_webhook_payload(
+            transcript_id=transcript_id,
+            room_id=room_id,
+        )
 
-        if transcript.topics:
-            # Build topics data with diarized content per topic
-            for topic in transcript.topics:
-                topic_webvtt = topics_to_webvtt([topic]) if topic.words else ""
-                topics_data.append(
-                    {
-                        "title": topic.title,
-                        "summary": topic.summary,
-                        "timestamp": topic.timestamp,
-                        "duration": topic.duration,
-                        "webvtt": topic_webvtt,
-                    }
-                )
+        if not payload:
+            log.error("Could not build webhook payload, skipping")
+            return
 
-        # Fetch meeting and calendar event if they exist
-        calendar_event = None
-        try:
-            if transcript.meeting_id:
-                meeting = await meetings_controller.get_by_id(transcript.meeting_id)
-                if meeting and meeting.calendar_event_id:
-                    calendar_event = await calendar_events_controller.get_by_id(
-                        meeting.calendar_event_id
-                    )
-        except Exception as e:
-            logger.error("Error fetching meeting or calendar event", error=str(e))
+        log.info(
+            "Sending webhook",
+            url=room.webhook_url,
+            topics=len(payload.transcript.topics),
+            participants=len(payload.transcript.participants),
+        )
 
-        # Build webhook payload
-        frontend_url = f"{settings.UI_BASE_URL}/transcripts/{transcript.id}"
-        participants = [
-            {"id": p.id, "name": p.name, "speaker": p.speaker}
-            for p in (transcript.participants or [])
-        ]
-        payload_data = {
-            "event": "transcript.completed",
-            "event_id": event_id,
-            "timestamp": datetime.now(timezone.utc).isoformat(),
-            "transcript": {
-                "id": transcript.id,
-                "room_id": transcript.room_id,
-                "created_at": transcript.created_at.isoformat(),
-                "duration": transcript.duration,
-                "title": transcript.title,
-                "short_summary": transcript.short_summary,
-                "long_summary": transcript.long_summary,
-                "webvtt": transcript.webvtt,
-                "topics": topics_data,
-                "participants": participants,
-                "source_language": transcript.source_language,
-                "target_language": transcript.target_language,
-                "status": transcript.status,
-                "frontend_url": frontend_url,
-                "action_items": transcript.action_items,
-            },
-            "room": {
-                "id": room.id,
-                "name": room.name,
-            },
-        }
+        response = await send_webhook_request(
+            url=room.webhook_url,
+            payload=payload,
+            event_type="transcript.completed",
+            webhook_secret=room.webhook_secret,
+            retry_count=self.request.retries,
+            timeout=30.0,
+        )
 
-        # Always include calendar_event field, even if no event is present
-        payload_data["calendar_event"] = {}
-
-        # Add calendar event data if present
-        if calendar_event:
-            calendar_data = {
-                "id": calendar_event.id,
-                "ics_uid": calendar_event.ics_uid,
-                "title": calendar_event.title,
-                "start_time": calendar_event.start_time.isoformat()
-                if calendar_event.start_time
-                else None,
-                "end_time": calendar_event.end_time.isoformat()
-                if calendar_event.end_time
-                else None,
-            }
-
-            # Add optional fields only if they exist
-            if calendar_event.description:
-                calendar_data["description"] = calendar_event.description
-            if calendar_event.location:
-                calendar_data["location"] = calendar_event.location
-            if calendar_event.attendees:
-                calendar_data["attendees"] = calendar_event.attendees
-
-            payload_data["calendar_event"] = calendar_data
-
-        # Convert to JSON
-        payload_json = json.dumps(payload_data, separators=(",", ":"))
-        payload_bytes = payload_json.encode("utf-8")
-
-        # Generate signature if secret is configured
-        headers = {
-            "Content-Type": "application/json",
-            "User-Agent": "Reflector-Webhook/1.0",
-            "X-Webhook-Event": "transcript.completed",
-            "X-Webhook-Retry": str(self.request.retries),
-        }
-
-        if room.webhook_secret:
-            timestamp = str(int(datetime.now(timezone.utc).timestamp()))
-            signature = generate_webhook_signature(
-                payload_bytes, room.webhook_secret, timestamp
-            )
-            headers["X-Webhook-Signature"] = f"t={timestamp},v1={signature}"
-
-        # Send webhook with timeout
-        async with httpx.AsyncClient(timeout=30.0) as client:
-            log.info(
-                "Sending webhook",
-                url=room.webhook_url,
-                payload_size=len(payload_bytes),
-            )
-
-            response = await client.post(
-                room.webhook_url,
-                content=payload_bytes,
-                headers=headers,
-            )
-
-            response.raise_for_status()
-
-            log.info(
-                "Webhook sent successfully",
-                status_code=response.status_code,
-                response_size=len(response.content),
-            )
+        log.info(
+            "Webhook sent successfully",
+            status_code=response.status_code,
+            response_size=len(response.content),
+        )
 
     except httpx.HTTPStatusError as e:
         log.error(
@@ -226,8 +116,8 @@ async def send_transcript_webhook(
 
 
 async def test_webhook(room_id: str) -> dict:
-    """
-    Test webhook configuration by sending a sample payload.
+    """Test webhook configuration by sending a sample payload.
+
     Returns immediately with success/failure status.
     This is the shared implementation used by both the API endpoint and Celery task.
     """
@@ -239,34 +129,25 @@ async def test_webhook(room_id: str) -> dict:
         if not room.webhook_url:
             return {"success": False, "error": "No webhook URL configured"}
 
-        now = (datetime.now(timezone.utc).isoformat(),)
-        payload_data = {
-            "event": "test",
-            "event_id": uuid.uuid4().hex,
-            "timestamp": now,
-            "message": "This is a test webhook from Reflector",
-            "room": {
-                "id": room.id,
-                "name": room.name,
-            },
-        }
+        payload = WebhookTestPayload(
+            event="test",
+            event_id=uuid.uuid4().hex,
+            timestamp=datetime.now(timezone.utc),
+            message="This is a test webhook from Reflector",
+            room=WebhookRoomPayload(
+                id=room.id,
+                name=room.name,
+            ),
+        )
 
-        payload_json = json.dumps(payload_data, separators=(",", ":"))
-        payload_bytes = payload_json.encode("utf-8")
+        payload_bytes = _serialize_payload(payload)
 
-        # Generate headers with signature
-        headers = {
-            "Content-Type": "application/json",
-            "User-Agent": "Reflector-Webhook/1.0",
-            "X-Webhook-Event": "test",
-        }
-
-        if room.webhook_secret:
-            timestamp = str(int(datetime.now(timezone.utc).timestamp()))
-            signature = generate_webhook_signature(
-                payload_bytes, room.webhook_secret, timestamp
-            )
-            headers["X-Webhook-Signature"] = f"t={timestamp},v1={signature}"
+        # Build headers with signature
+        headers = build_webhook_headers(
+            event_type="test",
+            payload_bytes=payload_bytes,
+            webhook_secret=room.webhook_secret,
+        )
 
         # Send test webhook with short timeout
         async with httpx.AsyncClient(timeout=10.0) as client: