Zoho ZeptoMail

Use the ZeptoMail API via curl to send transactional emails like password resets, OTPs, welcome emails, and order confirmations.

Official docs: https://www.zoho.com/zeptomail/help/api-home.html

When to Use

Use this skill when you need to:

Send transactional emails (password resets, OTPs, confirmations) Send templated emails with dynamic merge fields Batch send to multiple recipients (up to 500) Track email opens and clicks Send emails with attachments or inline images

Note: ZeptoMail is for transactional emails only. For marketing/bulk emails, use Zoho Campaigns instead.

Prerequisites Sign up at Zoho ZeptoMail Add and verify your domain Create a Mail Agent and get your Send Mail Token Get API Token Go to Mail Agents in ZeptoMail dashboard Click on your Mail Agent Go to SMTP & API tab Copy the Send Mail Token export ZEPTOMAIL_API_KEY="your-send-mail-token"

Pricing Free tier: 10,000 emails Paid: $2.50 per 10,000 emails

Important: When using $VAR in a command that pipes to another command, wrap the command containing $VAR in bash -c '...'. Due to a Claude Code bug, environment variables are silently cleared when pipes are used directly.

bash -c 'curl -s "https://api.example.com" -H "Authorization: Bearer $API_KEY"'

How to Use

Base URL: https://api.zeptomail.com/v1.1

Send Basic Email

Write to /tmp/zeptomail_request.json:

{ "from": { "address": "noreply@yourdomain.com", "name": "Your App" }, "to": [ { "email_address": { "address": "user@example.com", "name": "User" } } ], "subject": "Welcome to Our Service", "htmlbody": "

Welcome!

Thank you for signing up.

" }

Then run:

bash -c 'curl -s "https://api.zeptomail.com/v1.1/email" -X POST --header "Authorization: Zoho-enczapikey ${ZEPTOMAIL_API_KEY}" --header "Content-Type: application/json" -d @/tmp/zeptomail_request.json'

Send Plain Text Email

Write to /tmp/zeptomail_request.json:

{ "from": { "address": "noreply@yourdomain.com", "name": "Your App" }, "to": [ { "email_address": { "address": "user@example.com", "name": "User" } } ], "subject": "Your OTP Code", "textbody": "Your one-time password is: 123456\n\nThis code expires in 10 minutes." }

Then run:

Send Email with Tracking

Enable open and click tracking:

Write to /tmp/zeptomail_request.json:

{ "from": { "address": "noreply@yourdomain.com", "name": "Your App" }, "to": [ { "email_address": { "address": "user@example.com", "name": "User" } } ], "subject": "Order Confirmation #12345", "htmlbody": "

Your order has been confirmed. Track your order

", "track_clicks": true, "track_opens": true, "client_reference": "order-12345" }

Then run:

Send to Multiple Recipients (CC/BCC)

Write to /tmp/zeptomail_request.json:

{ "from": { "address": "noreply@yourdomain.com", "name": "Your App" }, "to": [ { "email_address": { "address": "user1@example.com", "name": "User 1" } } ], "cc": [ { "email_address": { "address": "user2@example.com", "name": "User 2" } } ], "bcc": [ { "email_address": { "address": "admin@example.com", "name": "Admin" } } ], "subject": "Team Update", "htmlbody": "

Here is the latest update for the team.

", "reply_to": [ { "address": "support@yourdomain.com", "name": "Support" } ] }

Then run:

Send Email with Attachment (Base64)

Encode file to base64

FILE_CONTENT=$(base64 -i /path/to/file.pdf)

Write to /tmp/zeptomail_request.json:

{ "from": { "address": "noreply@yourdomain.com", "name": "Your App" }, "to": [ { "email_address": { "address": "user@example.com", "name": "User" } } ], "subject": "Your Invoice", "htmlbody": "

Please find your invoice attached.

", "attachments": [ { "name": "invoice.pdf", "mime_type": "application/pdf", "content": "${FILE_CONTENT}" } ] }

Then run:

Send Email with Inline Image

Encode image to base64

IMAGE_CONTENT=$(base64 -i /path/to/logo.png)

Write to /tmp/zeptomail_request.json:

{ "from": { "address": "noreply@yourdomain.com", "name": "Your App" }, "to": [ { "email_address": { "address": "user@example.com", "name": "User" } } ], "subject": "Newsletter", "htmlbody": "

Welcome to our newsletter!

", "inline_images": [ { "cid": "logo", "name": "logo.png", "mime_type": "image/png", "content": "${IMAGE_CONTENT}" } ] }

Then run:

Send Templated Email

Use pre-defined templates with merge fields:

Write to /tmp/zeptomail_request.json:

{ "template_key": "your-template-key", "from": { "address": "noreply@yourdomain.com", "name": "Your App" }, "to": [ { "email_address": { "address": "user@example.com", "name": "User" } } ], "merge_info": { "user_name": "John", "order_id": "12345", "total": "$99.00" } }

Then run:

bash -c 'curl -s "https://api.zeptomail.com/v1.1/email/template" -X POST --header "Authorization: Zoho-enczapikey ${ZEPTOMAIL_API_KEY}" --header "Content-Type: application/json" -d @/tmp/zeptomail_request.json'

Template example (in ZeptoMail dashboard):

Hi {{user_name}},

Your order #{{order_id}} totaling {{total}} has been shipped!

Batch Send (Multiple Recipients)

Send to up to 500 recipients with personalized merge fields:

Write to /tmp/zeptomail_request.json:

{ "from": { "address": "noreply@yourdomain.com", "name": "Your App" }, "subject": "Your Monthly Report - {{month}}", "htmlbody": "

Hi {{name}},

Here is your report for {{month}}.

", "to": [ { "email_address": { "address": "user1@example.com", "name": "User 1" }, "merge_info": { "name": "Alice", "month": "December" } }, { "email_address": { "address": "user2@example.com", "name": "User 2" }, "merge_info": { "name": "Bob", "month": "December" } } ] }

Then run:

bash -c 'curl -s "https://api.zeptomail.com/v1.1/email/batch" -X POST --header "Authorization: Zoho-enczapikey ${ZEPTOMAIL_API_KEY}" --header "Content-Type: application/json" -d @/tmp/zeptomail_request.json'

Batch Send with Template

Write to /tmp/zeptomail_request.json:

{ "template_key": "your-template-key", "from": { "address": "noreply@yourdomain.com", "name": "Your App" }, "to": [ { "email_address": { "address": "user1@example.com", "name": "User 1" }, "merge_info": { "user_name": "Alice", "code": "ABC123" } }, { "email_address": { "address": "user2@example.com", "name": "User 2" }, "merge_info": { "user_name": "Bob", "code": "XYZ789" } } ] }

Then run:

bash -c 'curl -s "https://api.zeptomail.com/v1.1/email/template/batch" -X POST --header "Authorization: Zoho-enczapikey ${ZEPTOMAIL_API_KEY}" --header "Content-Type: application/json" -d @/tmp/zeptomail_request.json'

Response Format Success Response { "data": [ { "code": "EM_104", "additional_info": [], "message": "OK" } ], "message": "OK", "request_id": "abc123..." }

Error Response { "error": { "code": "TM_102", "details": [ { "code": "TM_102", "message": "Invalid email address", "target": "to" } ], "message": "Invalid request" }, "request_id": "abc123..." }

Common Error Codes Code Description TM_101 Authentication failed (invalid token) TM_102 Invalid request parameters TM_103 Domain not verified TM_104 Rate limit exceeded EM_104 Success Guidelines Transactional only - Do not use for marketing or bulk promotional emails Verify domain first - Sender address must be from a verified domain Size limit - Total email size (headers + body + attachments) must not exceed 15 MB Batch limit - Maximum 500 recipients per batch request Use templates - For consistent emails, create templates in the dashboard Track reference - Use client_reference to correlate emails with your transactions TLS required - API only supports TLS v1.2+

安装

Welcome!

Encode file to base64

Encode image to base64