Retell AI Webhooks

When to Use This Skill

• How do I receive Retell AI webhooks?
• How do I verify Retell webhook signatures (X-Retell-Signature)?
• How do I handle call_ended or call_analyzed events?
• Why is my Retell webhook signature verification failing?
• How do I handle transcript, transfer, and chat events from Retell?

Verification (core)

Retell signs each webhook with HMAC-SHA256 using your Retell API key as the secret (only an API key with the webhook badge in the dashboard works). The signature arrives in the X-Retell-Signature header formatted as v={unix_ms_timestamp},d={hex_digest}, where the digest is computed over the raw request body concatenated with the timestamp. Always verify against the raw body, never a re-serialized JSON string.