#!/bin/bash

# bash-curl-zerosmtp.sh

# Bash curl 8.10+ - ZeroSMTP mx.msgwing.com:465 SSL/TLS

# Production-ready | Let's Encrypt | POSIX heredoc

set -euo pipefail

error_exit() {

printf 'ERROR: %s\n' "$1" >&2

exit 1

}

trap 'error_exit "Script interrupted"' INT TERM

# Configuration from environment variables

# NOTE: names are prefixed with ZEROSMTP_ to avoid colliding with

# reserved/OS-level variables (e.g. USERNAME is auto-set on Windows).

USERNAME="${ZEROSMTP_USERNAME:-your-username}"

PASSWORD="${ZEROSMTP_PASSWORD:-your-password}"

FROM="${ZEROSMTP_FROM:-sender@example.com}"

TO="${ZEROSMTP_TO:-recipient@example.com}"

SUBJECT="${ZEROSMTP_SUBJECT:-Test Email from ZeroSMTP}"

# Validate inputs

[[ -z "$USERNAME" ]] && error_exit "ZEROSMTP_USERNAME not set"

[[ -z "$PASSWORD" ]] && error_exit "ZEROSMTP_PASSWORD not set"

[[ -z "$FROM" ]] && error_exit "ZEROSMTP_FROM not set"

[[ -z "$TO" ]] && error_exit "ZEROSMTP_TO not set"

# Build email body

EMAIL_BODY="From: $FROM\r\nTo: $TO\r\nSubject: $SUBJECT\r\nMIME-Version: 1.0\r\nContent-Type: text/plain; charset=UTF-8\r\n\r\nHello from ZeroSMTP! This is plain text sent via mx.msgwing.com:465"

# Send via curl with system CA verification

if curl \

--url "smtps://mx.msgwing.com:465" \

--user "$USERNAME:$PASSWORD" \

--mail-from "$FROM" \

--mail-rcpt "$TO" \

--upload-file <(printf '%b' "$EMAIL_BODY") \

--ssl-reqd \

--tlsv1.2 \

--connect-timeout 10 \

--max-time 30 \

--silent \

--show-error; then

printf 'Email sent successfully via ZeroSMTP\n'

exit 0

else

error_exit "Failed to send email via ZeroSMTP"

fi