Send Email

Send Email with SendGrid

Overview

SendGrid provides a single Mail Send endpoint for sending email via the v3 API. The Node SDK (@sendgrid/mail) is the recommended integration for JavaScript/TypeScript.

Use this skill when:

• Sending transactional emails (welcome, password reset, receipts)
• Sending simple notifications
• You need basic text/HTML emails with optional attachments
• Using dynamic templates for personalized content

Quick Start

Test Your Configuration First

# Validate API key and send test email
../scripts/send-test-email.sh recipient@example.com

Then integrate:

1. Detect project language (package.json, requirements.txt, go.mod, etc.)
2. Install SDK (preferred) or use cURL - See references/installation.md
3. Prepare message with from, to, subject, and text or html
4. Send and handle errors (retry on 429/5xx)

Required Parameters

Optional Parameters

Minimal Example (Node.js)

import sgMail from '@sendgrid/mail';

sgMail.setApiKey(process.env.SENDGRID_API_KEY!);

await sgMail.send({
  from: 'Support <support@winkintel.com>',
  to: 'vince@winkintel.com',
  subject: 'Hello from SendGrid',
  text: 'This is a test email.',
  html: '<p>This is a test email.</p>',
});

Templates (Dynamic Templates)

If using SendGrid Dynamic Templates, supply template_id and dynamic_template_data instead of html/text.

await sgMail.send({
  from: 'Support <support@winkintel.com>',
  to: 'vince@winkintel.com',
  templateId: 'd-xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx',
  dynamicTemplateData: { first_name: 'Vince' },
});

Decision: Plain Send vs Dynamic Templates?

How complex is your email?
├─ Simple, one-off message
│  └─ Plain send (html/text) ✅
├─ Reusable design with variables
│  └─ Dynamic Template ✅
└─ Personalized at scale
   └─ Dynamic Template with merge tags ✅

Use plain send when:

• Quick, simple messages
• Content changes every time
• No design reusability needed

Use dynamic templates when:

• Consistent design across emails
• Variable substitution (names, dates, etc.)
• Non-technical teams manage email content
• A/B testing email designs

Troubleshooting

"401 Unauthorized":

• API key invalid or missing
• Check SENDGRID_API_KEY environment variable
• Verify key has mail send permissions

"403 Forbidden":

• Sender email not verified
• Go to SendGrid Console → Settings → Sender Authentication
• Verify single sender or authenticate domain

"429 Too Many Requests":

• Rate limit exceeded
• Implement exponential backoff (retry after 1s, 2s, 4s...)
• Consider upgrading SendGrid plan

"500/503 Service Errors":

• SendGrid temporary service issue
• Retry with exponential backoff
• Check SendGrid status page

Emails not arriving:

• Check recipient spam folder
• Verify sender domain authentication (SPF/DKIM)
• Use both text and html for better deliverability
• Avoid spam trigger words in subject/body

Best Practices (Short)

• Always set both text and html when possible (deliverability + accessibility).
• Retry only on 429 or 5xx errors with exponential backoff.
• Use verified senders; unverified domains will fail.
• Avoid fake addresses at real providers; test with addresses you control.

For deeper details, see:

• references/best-practices.md
• references/single-email-examples.md

Automation Scripts

Quick testing:

• scripts/send-test-email.sh - Send plain text test email (API key validation)
• scripts/send-html-email.sh - Send HTML email (newsletters, reports, formatted content)

See scripts/README.md for usage examples.

Related Skills

Receiving email responses:

• See sendgrid-inbound for handling incoming emails via Inbound Parse Webhook
• Common use case: Auto-reply systems, support ticket creation from email