Sendgrid Send Email

SendGrid Send Email

Send email through SendGrid's v3 Mail Send API.

Purpose

This skill is for sending transactional email with SendGrid by calling POST /v3/mail/send directly.

Inputs:

• from verified sender email. This address should be a verified sender in your Twilio SendGrid account.
• one or more to recipients
• subject, unless the subject is defined by a dynamic template
• text, html, or template_id
• SendGrid API key from --api-key, SENDGRID_API_KEY, or the locally saved key
• automatic custom_args.business_id for application-side correlation, or user-provided --business-id

Output:

• dry-run JSON payload by default
• SendGrid HTTP status, message metadata, and one status-query prompt example when --send is explicitly provided

Sending email is irreversible once queued. Always confirm recipients, subject, and content with the user before running with --send.

What This Skill Needs

• user-provided sender. This address should be a verified sender in the user's Twilio SendGrid account.
• user-provided recipients and message content
• a SendGrid API key, usually SENDGRID_API_KEY
• curl
• bash
• python3

SendGrid API keys are separate from Twilio Account SID/Auth Token credentials. Do not use this skill for the separate Twilio Email API at comms.twilio.com.

API key resolution order:

1. --api-key for the current run
2. SENDGRID_API_KEY
3. locally saved key at ~/.config/sendgrid-send-email/api_key

If no API key is available and the script is running interactively, prompt once and save it locally for future runs. If no API key is available in a non-interactive run, guide the user to read the SendGrid integration guide: https://frevana.gitbook.io/frevana-docs/email-integrations/sendgrid-integration.

Users can update the saved API key with:

bash <skill-path>/scripts/send_email.sh --api-key "SG..." --save-api-key

or clear it with:

bash <skill-path>/scripts/send_email.sh --clear-api-key

Execution Order

1. Confirm the user explicitly wants to send email and has provided the final recipients, subject, and content.
2. Prefer the bundled script over ad hoc curl commands.
3. Run a dry run first unless the user already asked for an immediate send and the final email details are unambiguous.
4. Review the dry-run payload for recipient visibility, content, attachments, sandbox mode, and scheduled-send fields.
5. Run again with --send only after explicit user approval.
6. Treat HTTP 202 as queued, not delivered. Delivery confirmation is asynchronous through SendGrid Email Logs, event webhooks, or the sendgrid-email-log skill.
7. Report the recipients, subject, business ID, sandbox/send mode, HTTP status, SendGrid x-message-id header, and a concise prompt example for querying status with sendgrid-email-log when available.

Commands

Dry-run a simple email

bash <skill-path>/scripts/send_email.sh \
  --from "verified@example.com" \
  --to "recipient@example.com" \
  --subject "Hello" \
  --text "Hello from SendGrid."

Actually send

bash <skill-path>/scripts/send_email.sh \
  --from "verified@example.com" \
  --to "recipient@example.com" \
  --subject "Hello" \
  --html "<p>Hello from SendGrid.</p>" \
  --send

Multiple recipients with private personalizations

bash <skill-path>/scripts/send_email.sh \
  --from "verified@example.com" \
  --to "alice@example.com" \
  --to "bob@example.com" \
  --subject "Private update" \
  --text "Each recipient is in a separate personalization." \
  --private-recipients \
  --send

Without --private-recipients, recipients in the same to array can see each other.

Dynamic template send

bash <skill-path>/scripts/send_email.sh \
  --from "verified@example.com" \
  --to "alice@example.com" \
  --template-id "d-xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx" \
  --dynamic-template-data-json '{"name":"Alice","order_id":"123"}' \
  --send

When using --template-id, omit --text and --html unless the user specifically wants both. Template content normally comes from SendGrid.

Sandbox validation

bash <skill-path>/scripts/send_email.sh \
  --from "verified@example.com" \
  --to "recipient@example.com" \
  --subject "Validate only" \
  --text "This request is validated but not delivered." \
  --sandbox \
  --send

Sandbox mode validates the request without delivery and usually returns HTTP 200.

Attach a file

bash <skill-path>/scripts/send_email.sh \
  --from "verified@example.com" \
  --to "customer@example.com" \
  --subject "Invoice" \
  --html-file ./email.html \
  --attachment ./invoice.pdf \
  --send

Attachments are base64-encoded into the attachments array. Keep total request size under SendGrid's documented limit.

Add a business correlation ID

Every request automatically includes custom_args.business_id. To control the value, pass:

bash <skill-path>/scripts/send_email.sh \
  --from "verified@example.com" \
  --to "customer@example.com" \
  --subject "Order update" \
  --text "Your order shipped." \
  --business-id "order_12345"

Use this ID later when correlating SendGrid Event Webhook events or application logs. Do not use it as the default Email Logs query path.

Fixed Request Shape

The script sends to:

• global region: https://api.sendgrid.com/v3/mail/send
• EU region: https://api.eu.sendgrid.com/v3/mail/send

It sends JSON shaped like:

{
  "personalizations": [
    {
      "to": [{ "email": "recipient@example.com" }],
      "dynamic_template_data": { "name": "Alice" }
    }
  ],
  "from": { "email": "verified@example.com" },
  "subject": "Hello",
  "content": [{ "type": "text/plain", "value": "Hello from SendGrid." }],
  "custom_args": {
    "business_id": "sendgrid_email_20260615T120000Z_0123456789abcdef0123456789abcdef"
  }
}

Optional fields are omitted when the user does not provide them. Require --from from the user. Do not invent sender identities, recipients, template IDs, categories, custom args, batch IDs, or scheduled-send timestamps.

Script Options

• --from EMAIL or --from "Name <email@example.com>"; required sender address. This address should be a verified sender in the user's Twilio SendGrid account.
• --to, --cc, --bcc; repeat flags or comma-separate values
• --subject
• --text, --text-file
• --html, --html-file
• --template-id
• --dynamic-template-data-json
• --reply-to
• --attachment PATH; repeatable
• --business-id VALUE; optional business correlation ID. Auto-generated when omitted and written to custom_args.business_id
• --category NAME; repeatable, up to SendGrid's limit
• --custom-arg KEY=VALUE; repeatable
• --batch-id
• --send-at UNIX_SECONDS
• --sandbox
• --private-recipients
• --region global|eu
• --api-key KEY for a one-time override
• --save-api-key to save the --api-key value for future runs
• --configure-api-key to prompt for and save the key
• --clear-api-key to remove the locally saved key
• --output PATH to save dry-run JSON or send metadata
• --send to perform the API call

Notes

• --send is required for side effects; without it, the script only prints the payload.
• Never echo or store the API key in user-visible output.
• The scripts can save the API key locally at ~/.config/sendgrid-send-email/api_key with file permission 600; do not print the key value back to the user.
• Use --api-key <key> --save-api-key or --configure-api-key when the user wants to update the saved key. Use --clear-api-key when the user wants to remove it.
• The from address should be a verified sender in the user's Twilio SendGrid account.
• Every request includes custom_args.business_id. Use --business-id to set a business-specific correlation ID; otherwise the script generates one.
• Do not pass --custom-arg business_id=...; use --business-id for that reserved key.
• Use sendgrid-email-log for Email Logs status queries, per-message event timelines, and opened/clicked checks.
• After a successful send, the script returns status_query.prompt_example and status_query.query_params so the user can ask the agent to query status later without displaying shell scripts.
• If --api-key, SENDGRID_API_KEY, and the locally saved key are all missing, tell the user to read https://frevana.gitbook.io/frevana-docs/email-integrations/sendgrid-integration to get the required configuration.
• SendGrid returns 202 Accepted for queued mail. That does not mean delivered.
• Sandbox mode returns validation status and does not deliver.
• For scheduled sends, --send-at must be Unix seconds, not JavaScript milliseconds.
• For private bulk sends, use --private-recipients or separate API calls.
• If a user shares an API key in chat, advise them to rotate it.

Example Prompts

中文

• "用 SendGrid 给 alice@example.com 发一封测试邮件"
• "用这个 verified sender 发送 HTML 邮件，先 dry run"
• "用 SendGrid template d-... 给这几个收件人分别发邮件"

English

• "Send a SendGrid email to this customer"
• "Dry-run this SendGrid Mail Send payload before sending"
• "Send a SendGrid dynamic template email with these variables"