SparkPost Webhooks

When to Use This Skill

• How do I receive SparkPost webhooks?
• How do I authenticate SparkPost webhooks? (there is no signature to verify)
• Why is my SparkPost webhook returning 401 / why won't SparkPost create my webhook?
• How do I parse the SparkPost msys batch payload?
• How do I handle delivery, bounce, click, open, spam_complaint events?
• What is X-MessageSystems-Batch-ID and how do I deduplicate batches?
• How do I handle SparkPost relay webhooks (inbound email)?

Critical: SparkPost Event Webhooks Are Not Signed

There is no HMAC, no signature header, and no signing secret. Do not look for one — any code that computes createHmac / hmac.new for a SparkPost event webhook is wrong.