In this quick tutorial, I will show you how to send email using the standard library. In the end of this tutorial, you will be able to send a Newsletter email looking as below: HTML Go Before I start, all the code used in this demo can be found on my . Github 1 — HTML Template Coding Email template is one of tasks that brings tears to a developer’s eyes because of the vast differences in rendering between email clients. don’t render HTML in the same way as do. like , and even should not be part of your vocabulary while creating an HTML email template. So how to create a nice HTML email template then ? HTML/CSS Email clients browsers CSS properties float background-image margins Think back to 1999 which means , , , . All those shitty things you thought you’d left behind are now your closest friends. Tables cellpadding cellspacing colspan In my experience, HTML email code gets very complicated, very quickly. So it’s always better to keep it simple and start with a plan: So we will start off with our wrapper table with 100% as width and white background. I used and HTML attributes. Think of them like using and CSS properties: cellpadding cellspacing margin padding Note: There are 4 rows inside the table: one at top for the header one in the middle for the main content one for the subscription button one at the bottom for the footer Now we can start the process of coding our newsletter, section by section: 1.1 — Header The header is pretty simple, it’s one column, and a text in the center of a row: 1.2 — Content Our content section is quite simple, it’s just a paragraph, so the coding is straighforward: Note: The {{ .username }} part will be replaced with the receiver name while parsing the HTML template by the before sending the Email. template engine 1.3 — Subscription Button Now comes the most difficult part, are not supported in most of email clients, Therefore, we have to use and : button element tables table cells Note: that we’re using instead of CSS property. This is because HTML values are better supported in email clients than CSS properties. bgcolor background This is just one way to implement buttons in email. Admittedly, it doesn’t always look identical in every client, but the web is not always pixel-perfect either. I prefer this because it’s simpler and doesn’t involve using or image assets VML 1.4 — Footer Footer is just repeating what we’ve already done on the header part. Note: Don’t forget to add the : meta tags Viewport: <meta name=”viewport” content=”width=device-width”/> It used to tell the browser that your email is responsive and can adapt to small screens like tablets and smartphones. Charset: <meta http-equiv=”Content-Type” content=”text/html; charset=UTF-8" /> It’s important in order to preserve the character encoding across various email clients. And the main layout is now complete: 2 — Coding Part 2.2 — Mailer It’s responsible for parsing the HTML template and send an Email 2.3 — Mailer Configuration Responsible for mapping the configuration file into a object Config Configuration file has the information: SMTP server server=”smtp.gmail.com” port=587 email=”YOUR EMAIL ADDRESS” password=”EMAIL PASSWORD” Note: The code above uses an external library to parse the config file, so be sure to grab it by typing the following command: go get github.com/BurntSushi/toml 2.4 — Main application It creates a new request with the mail subject and receiver email, then calls the method: Send 3 — Testing There are a lot of clients to test, and a lot of ways to test them, let’s go over a small sets of : Email Clients 3.1 — Yahoo 3.2 — Gmail 3.3 — Mozilla Thunderbird 3.4 — Microsoft Outlook 3.5 — Android Email (5.0) So as you can notice above the template we created is also responsive.
