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Monitoring Deliveries

Track individual webhook delivery attempts to subscriber endpoints and monitor delivery success rates.

What are Deliveries?​

Deliveries are individual attempts to send a webhook to a subscriber's endpoint. When you send an event, hookVM creates a delivery for each active subscription listening to that event type.

Delivery Flow:

  1. Event is sent
  2. Matching subscriptions are found
  3. Delivery is created for each subscription
  4. Webhook is sent to subscriber endpoint
  5. Response is recorded
  6. Retries occur if needed

Deliveries Page​

View and monitor all webhook delivery attempts and their statuses.

Deliveries List

Key Features​

Delivery Tracking: See all delivery attempts
Status Monitoring: Track success/failure
Response Codes: View HTTP response codes
Attempt Tracking: See retry attempts
Filtering: Filter by status, endpoint
Debugging: Identify delivery issues

Delivery Columns​

EVENT ID​

The unique identifier of the event that was delivered.

Format: Truncated ID (e.g., 78278cb7...)

Use Cases:

  • Link to original event
  • Track event lifecycle
  • Debug event-specific issues

ENDPOINT URL​

The subscriber's webhook URL where the delivery was attempted.

Format: Full HTTPS URL (truncated for display)

Example:

https://webhook.site/4ap7c02-6b5c-48ad-906...

Use Cases:

  • Identify which subscriber
  • Verify correct endpoint
  • Debug endpoint-specific issues

STATUS​

Delivery status indicating success or failure.

SUCCESS (Green badge):

  • Webhook delivered successfully
  • Received 2xx response code
  • No retries needed

FAILED (Red badge):

  • Delivery failed
  • After all retry attempts
  • Requires investigation

PENDING (Yellow badge):

  • Delivery in progress
  • Waiting for response
  • May still succeed

RETRYING (Orange badge):

  • Previous attempt failed
  • Retry in progress
  • Will retry based on config

ATTEMPT​

Which delivery attempt this represents.

Format: #{number}

Examples:

  • #1 - First attempt (immediate)
  • #2 - Second attempt (after retry)
  • #3 - Third attempt (after second retry)

Use Cases:

  • Track retry behavior
  • Identify persistent failures
  • Understand delivery timeline

RESPONSE​

HTTP response code from the subscriber's endpoint.

Format: 3-digit HTTP status code

Success Codes (2xx):

  • 200 - OK (success)
  • 201 - Created (success)
  • 202 - Accepted (success)
  • 204 - No Content (success)

Client Error Codes (4xx):

  • 400 - Bad Request
  • 401 - Unauthorized
  • 403 - Forbidden
  • 404 - Not Found
  • 422 - Unprocessable Entity

Server Error Codes (5xx):

  • 500 - Internal Server Error
  • 502 - Bad Gateway
  • 503 - Service Unavailable
  • 504 - Gateway Timeout

No Response:

  • Empty - Network error, timeout, or DNS failure

DELIVERED AT​

Timestamp when the delivery attempt was made.

Format: YYYY-MM-DD HH:MM:SS

Example: 2025-12-27 16:36:46

Use Cases:

  • Track delivery timing
  • Identify delays
  • Debug timing issues

ACTIONS​

Quick actions for each delivery.

View Details (Eye icon):

  • View full delivery details
  • See request/response
  • Review headers and body

Filtering Deliveries​

Use filters to find specific deliveries quickly.

Filter by Status​

Dropdown: "All Statuses"

Options:

  • All Statuses
  • Success
  • Failed
  • Pending
  • Retrying

Use Case: Focus on failed deliveries for troubleshooting

Search by Endpoint URL​

Search Box: "Search by endpoint URL..."

Type to search for deliveries to specific endpoints.

Use Case: Find all deliveries to a customer's endpoint

Understanding Delivery Status​

Success (2xx Responses)​

Status: SUCCESS
Response: 200, 201, 202, 204
Meaning: Webhook delivered successfully
Action: None needed

What Happens:

  • Delivery marked as complete
  • No retries attempted
  • Subscriber received webhook

Client Errors (4xx Responses)​

Status: FAILED
Response: 400, 401, 403, 404, 422
Meaning: Subscriber rejected the webhook
Action: Fix subscriber endpoint or payload

What Happens:

  • Delivery marked as failed
  • No retries (client error)
  • Requires manual intervention

Common Causes:

  • Invalid payload format (400)
  • Missing authentication (401)
  • Endpoint not found (404)
  • Validation error (422)

Server Errors (5xx Responses)​

Status: RETRYING → FAILED
Response: 500, 502, 503, 504
Meaning: Subscriber's server error
Action: Wait for retries or contact subscriber

What Happens:

  • Delivery retried automatically
  • Exponential backoff applied
  • Marked as failed after max retries

Common Causes:

  • Subscriber server down (503)
  • Timeout (504)
  • Internal error (500)
  • Gateway issue (502)

Network Errors​

Status: RETRYING → FAILED
Response: (empty)
Meaning: Network connectivity issue
Action: Verify endpoint URL and accessibility

What Happens:

  • Delivery retried automatically
  • Exponential backoff applied
  • Marked as failed after max retries

Common Causes:

  • DNS resolution failure
  • Connection timeout
  • Connection refused
  • Network unreachable

Retry Behavior​

Retry Strategy​

hookVM uses exponential backoff for retries:

Attempt 1: Immediate
Attempt 2: After 1 second (1000ms backoff)
Attempt 3: After 2 seconds (2000ms backoff)
Attempt 4: After 4 seconds (4000ms backoff)
Attempt 5: After 8 seconds (8000ms backoff)

When Retries Occur​

Retried:

  • 5xx server errors
  • Network timeouts
  • Connection failures
  • DNS resolution failures

Not Retried:

  • 2xx success codes
  • 4xx client errors
  • Invalid endpoint URL

Maximum Attempts​

Configured per subscription (default: 3 attempts).

Example Timeline:

Attempt 1: 16:36:46 - FAILED (500)
Attempt 2: 16:36:47 - FAILED (500) [1s later]
Attempt 3: 16:36:49 - FAILED (500) [2s later]
Final Status: FAILED after 3 attempts

Viewing Delivery Details​

Click on any delivery to view full details.

Request Information​

Headers:

{
  "Content-Type": "application/json",
  "X-HookVM-Signature": "t=1640000000,v1=abc123...",
  "X-HookVM-Event-ID": "evt_abc123",
  "X-HookVM-Event-Type": "order.shipped",
  "User-Agent": "HookVM-Webhooks/1.0"
}

Body:

{
  "event_id": "evt_abc123",
  "event_type": "order.shipped",
  "occurred_at": "2025-12-27T10:00:00Z",
  "data": {
    "order_id": "ord_12345",
    "tracking_number": "TRK789",
    "carrier": "UPS"
  }
}

Response Information​

Status Code: 200
Response Time: 245ms
Response Headers:

{
  "Content-Type": "application/json",
  "X-Request-ID": "req_xyz789"
}

Response Body:

{
  "success": true,
  "message": "Webhook received"
}

Common Workflows​

Debugging Failed Deliveries​

  1. Filter by Failed: Show only failed deliveries
  2. Check Response Code: Identify error type
  3. View Details: Inspect request/response
  4. Identify Pattern: Look for common issues
  5. Fix Issue: Update endpoint or contact subscriber

Monitoring Subscriber Health​

  1. Search by Endpoint: Find subscriber's deliveries
  2. Check Success Rate: Count success vs failures
  3. Review Response Times: Identify slow endpoints
  4. Alert on Failures: Set up monitoring alerts

Investigating Delays​

  1. Filter by Date: Select time period
  2. Review Timestamps: Check delivery timing
  3. Check Attempts: See retry delays
  4. Identify Bottlenecks: Find slow subscribers

Verifying Delivery​

  1. Search by Event ID: Find event's deliveries
  2. Check Status: Verify all succeeded
  3. Review Responses: Confirm subscriber received
  4. Cross-Reference: Match with subscriber logs

Delivery Metrics​

Success Rate​

Calculate delivery success rate:

Success Rate = (Successful Deliveries / Total Deliveries) × 100%

Example:

Successful: 950
Failed: 50
Total: 1000
Success Rate: 95%

Average Response Time​

Track subscriber endpoint performance:

Avg Response Time = Sum of Response Times / Number of Deliveries

Benchmarks:

  • Fast: < 200ms
  • Normal: 200-500ms
  • Slow: 500-1000ms
  • Very Slow: > 1000ms

Retry Rate​

Track how often retries are needed:

Retry Rate = (Deliveries with Retries / Total Deliveries) × 100%

Example:

Deliveries with Retries: 100
Total Deliveries: 1000
Retry Rate: 10%

Best Practices​

Monitoring​

✅ Check Daily: Review failed deliveries
✅ Track Trends: Monitor success rates over time
✅ Set Alerts: Alert on high failure rates
✅ Review Slow Endpoints: Identify performance issues

Debugging​

✅ Check Response Codes: Start with HTTP status
✅ Review Payloads: Verify data format
✅ Test Endpoints: Manually test subscriber URLs
✅ Contact Subscribers: Notify of persistent issues

Performance​

✅ Monitor Response Times: Track endpoint speed
✅ Identify Bottlenecks: Find slow subscribers
✅ Optimize Payloads: Keep data minimal
✅ Batch When Possible: Reduce delivery volume

Reliability​

✅ Configure Retries: Set appropriate retry counts
✅ Monitor Retry Rates: Track retry frequency
✅ Handle 4xx Errors: Fix client errors quickly
✅ Coordinate with Subscribers: Ensure endpoint health

Troubleshooting​

All Deliveries Failing​

Possible Causes:

  • Subscriber endpoint down
  • Invalid endpoint URL
  • Network issues
  • Authentication problems

Solutions:

  1. Test endpoint with curl
  2. Verify endpoint URL is correct
  3. Check network connectivity
  4. Verify authentication headers

High Retry Rate​

Possible Causes:

  • Subscriber endpoint unstable
  • Timeouts
  • Intermittent errors

Solutions:

  1. Contact subscriber about stability
  2. Increase timeout settings
  3. Review subscriber logs
  4. Consider reducing retry count

Slow Deliveries​

Possible Causes:

  • Subscriber endpoint slow
  • Large payloads
  • Network latency

Solutions:

  1. Monitor response times
  2. Optimize payload size
  3. Contact subscriber about performance
  4. Consider timeout adjustments

Missing Deliveries​

Possible Causes:

  • No active subscriptions
  • Event type mismatch
  • Subscription disabled

Solutions:

  1. Verify subscriptions exist
  2. Check event types match
  3. Ensure subscriptions are enabled

API Access​

Access delivery data programmatically.

List Deliveries​

curl -X GET "https://api.hookvm.com/v1/deliveries?status=failed&limit=100" \
  -H "Authorization: Bearer YOUR_API_KEY"

Get Delivery Details​

curl -X GET "https://api.hookvm.com/v1/deliveries/del_abc123" \
  -H "Authorization: Bearer YOUR_API_KEY"

Filter by Event​

curl -X GET "https://api.hookvm.com/v1/events/evt_abc123/deliveries" \
  -H "Authorization: Bearer YOUR_API_KEY"

Next Steps​

Monitor your deliveries to ensure reliable webhook delivery to all subscribers! 📊