SendGrid

1. Email API getting started

   Sending email with the v3 Mail Send API and API keys.

2. API keys

   Creating API keys with scoped permissions.

3. Domain authentication

   Authenticating a domain with SPF and DKIM.

4. Personalizations

   Per-recipient personalizations, substitutions and recipients.

5. Dynamic templates

   Dynamic templates using Handlebars.

6. SMTP relay

   Sending through the SMTP relay.

7. Event webhook

   The Event Webhook for delivery, bounce, open and click events.

8. Inbound parse

   The Inbound Parse webhook that turns incoming email into HTTP posts.

9. Suppressions

   Bounces, blocks, spam reports and unsubscribe suppressions.

10. IP warmup

    Warming up a dedicated IP to build sending reputation.

11. Deliverability

    Deliverability concepts such as reputation and authentication.

12. Single Sends (marketing email)

    Contacts and Single Sends for marketing email.

13. Rate limits

    Rate limits on the v3 API and how to handle them.

Each section links to the official page. Titles and summaries by Extra Credit; the docs belong to their authors.