The Email API lets you send and manage email through a modern RESTful interface with JSON support, templates, and detailed event tracking. It’s flexible, scalable, and built for automation. SMTP relay connects your app to Twilio SendGrid’s SMTP server to send messages, no coding required. It’s simpler but less customizable and harder to scale. Learn more here.

Sign up for a SendGrid account, create an API key, and use an official SDK (like Python, Node.js, or Java) to make a POST request to the /mail/send endpoint. You’ll get a status code response confirming your email was accepted for delivery, and you can usually send your first one in under 10 minutes. Our quickstart guides walk you through each step in your preferred programming language.

Create API keys with only the permissions you need, label them clearly, and rotate them regularly. Store keys in environment variables or a secret manager (never in source code or public repos). You can manage scopes and revoke compromised keys anytime in the Twilio SendGrid dashboard to keep your access safe and under control.

Use Twilio SendGrid’s Email Activity API, Event Webhook, or the Activity dashboard to monitor performance in real time. You can track deliveries, opens, clicks, bounces, unsubscribes, and spam reports. Plus, you can filter by message ID, event type, or date. Integrate the Event Webhook to stream delivery and engagement data directly into your own systems for analysis or alerts.

Start by building trust with inbox providers. Warm up dedicated IPs, authenticate your domain (SPF, DKIM, DMARC), and keep marketing and transactional sends on separate subdomains. Maintain a clean, engaged contact list and avoid spammy language or design tricks. Use Twilio’s Deliverability Center to track performance, spot issues, and stay in the inbox. Download our Deliverability Guide to learn more.

Yes. Use separate subdomains for different email types to protect your sender reputation. Marketing emails tend to get lower engagement, which can affect inbox placement. Keeping them apart (for example, news.example.com for marketing and alerts.example.com for transactional) helps inbox providers judge each stream on its own and keeps your important messages flowing reliably.

The Email API uses rate limits to keep traffic stable and fair. If you hit an error, slow down and retry with exponential backoff. Monitor your responses, spread out large sends, and avoid sudden spikes. For high-volume traffic, segment sends over time or across IPs. 

Absolutely. Use dynamic transactional templates with Handlebars syntax to personalize emails for each recipient. Create and manage templates in the UI, then reference them in your API calls with a template ID. You can inject custom data per message to scale personalized content like order confirmations, password resets, or onboarding emails without writing each one manually.