of 3— Get Your ESP API Credentials

What you'll accomplish

By the end of this guide, you'll have a weekly email performance report that writes itself — pulling campaign data from your ESP, sending it to the Claude API for analysis and narrative writing, and delivering a polished report to your inbox or Slack channel every Monday morning. No manual data pulling, no writing the same narrative structure week after week.

What you'll need

Zapier account (Professional plan, $49+/month — required for multi-step zaps with API calls)
Claude API access (console.anthropic.com — pay per use, ~$2-5/month for weekly reports)
ESP with API access (Klaviyo, Mailchimp, HubSpot all have reporting APIs)
Gmail or Slack for report delivery
Basic understanding of how APIs work (you don't need to code, but knowing what an API key is helps)
Time needed: 3-4 hours to build; 0 minutes per week after
Cost: $49+/month (Zapier) + ~$3/month (Claude API)

Advanced Guide: Automate Email Performance Reporting with Zapier + Claude API

Step 1: Get Your ESP API Credentials

Klaviyo:

Account → Settings → API Keys
Create a Private API Key with scopes: Campaigns:Read, Metrics:Read
Copy the key

Mailchimp:

Account → Extras → API Keys → Create A Key
Copy the key (also note your Data Center — e.g., "us14")

HubSpot:

Settings → Integrations → Private Apps → Create Private App
Scopes needed: content (for email campaigns), reports (for analytics)
Copy the access token