Sendgrid

Overview

The SendGrid (Twilio SendGrid) v3 API sends transactional and marketing email, manages verified senders, templates, and analytics. Auth is a simple API key (verified: requests without one return 401). The free tier covers light sending for personal projects.

Quick Start

Send an email (replace YOUR_KEY):

curl -X POST "https://api.sendgrid.com/v3/mail/send" \
  -H "Authorization: Bearer YOUR_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "personalizations": [{"to": [{"email": "[email protected]"}]}],
    "from": {"email": "[email protected]"},
    "subject": "Hello",
    "content": [{"type": "text/plain", "value": "Hello from SendGrid!"}]
  }'

Stats:

curl "https://api.sendgrid.com/v3/stats" -H "Authorization: Bearer YOUR_KEY"

Verified senders / templates:

curl "https://api.sendgrid.com/v3/verified_senders" -H "Authorization: Bearer YOUR_KEY"
curl "https://api.sendgrid.com/v3/templates" -H "Authorization: Bearer YOUR_KEY"

Authentication

• Create an API key at app.sendgrid.com (Settings → API Keys), with scopes (e.g. mail.send).
• Send it as Authorization: Bearer YOUR_KEY (an invalid key returns 401 — verified).
• Requires a verified sender (domain or single sender) before sending.

Rate Limits & Notes

• Free tier: 100 emails/day; paid plans scale.
• The mail/send endpoint is the workhorse — supports attachments, templates, and dynamic fields.
• All requests go through api.sendgrid.com/v3/; errors come back as JSON with a message.
• Consider the Inbound Parse webhook for receiving email (separate setup).

FAQ

Is SendGrid free? Free tier: 100 emails/day; paid plans scale up.

How do I get a key? app.sendgrid.com → Settings → API Keys → Create.

Do I need a verified sender? Yes — verify a domain or single sender before sending.