
This tutorial is part of the Building Your Startup With PHP series on Envato Tuts+. In this series, I'm guiding you through launching a startup from concept to reality using my Meeting Planner app as a real-life example. Every step along the way, I'll release the Meeting Planner code as open-source examples you can learn from. I'll also address startup-related business issues as they arise.
In our earlier episode, Delivering Invitations, I introduced responsive, HTML email templates which we built on some open-source MailChimp templates. Then, in our previous episode, Refining Email Templates, we migrated to the Sendwithus Oxygen templates. The new templates looked great:

But there were big problems with the templates in Gmail. Here's the Oxygen reference template in Gmail:

In this tutorial, I'll tell the story of how I cleaned up the appearance of the new HTML templates within Gmail. It has to do with inlining the CSS because the geniuses at Google don't support style definitions like everyone else.
Since likely half of people's first experience with Meeting Planner will be via a Meeting Request email and probably 10 to 25 percent of those may be with Gmail, this was important to fix.
If you haven't tried out Meeting Planner yet, go ahead and schedule your first meeting. I do participate in the comment threads below, so tell me what you think! You can also reach me on Twitter @reifman. I'm especially interested if you want to suggest new features or topics for future tutorials.
As a reminder, all of the code for Meeting Planner is written in the Yii2 Framework for PHP. If you'd like to learn more about Yii2, check out our parallel series Programming With Yii2.
For email templates, I decided to go with Sendwithus's Oxygen email templates. Oxygen offered a complete family of templates for useful scenarios. It seemed simple, organized, and easily extensible:

Each of Sendwithus's individual templates can be previewed and tested on their Litmus account.
Here's our reset your password email now on an iPhone, much more aesthetically comfortable than before:

I was a bit confused when the first Gmail attempts I received looked malformed to me:

But reviewing their Litmus previews (which they've since updated and repaired), showed me that that's just what they look like in Gmail:

I later learned that Gmail requires more inlining of CSS than other services. My task was to solve this problem for Meeting Planner users.
Initially, I thought we would need to manage the CSS inlining for Gmail ourselves. There were two paths to take, neither easy.
Either a) I could have processed every outbound message through a self-hosted, Python premailer after it was fully constructed, or, b) I could apply inlining to the templates within the source tree.
For simplicity, I chose to apply inlining to the templates manually, thinking I might opt for live inlining in the future. I'm not as familiar with running Python tasks from PHP and monitoring their performance on a critical feature such as emailed meeting invitations, so I decided not to go this route initially. Similarly, if I need to send an email to all 10,000 users, that's 10,000 inlining events, which could slow the server down.
Still, the approach I chose was not easy and turned into a bit of a procedural nightmare. There wasn't an easy way to programmatically generate HTML that could be easily processed and then returned to PHP for dynamic email generation.
Peter Bengtsson's Premailer inlines CSS for you via Python. He also helpfully pointed me to Premailer.io, which made things easier.
Basically, you copy and paste your email template into the Textarea tab and click the Convert button (not shown):

Then you can copy and paste the resulting email template with CSS inlined:

Here's a better view of HTML with CSS inlined—notice embedded styles with every HTML tag, the way Gmail engineers like it:
<tr>
<td align="center" valign="top" width="100%" style="color:#777; font-family:Helvetica, Arial, sans-serif; font-size:14px; line-height:21px; text-align:center; padding:20px 0 30px; background-color:#f7f7f7" bgcolor="#f7f7f7">
<center>
<table cellspacing="0" cellpadding="0" width="600" style="border-collapse:collapse">
<tr>
<td style="color:#4d4d4d; font-family:Helvetica, Arial, sans-serif; font-size:32px; line-height:normal; text-align:center; border-collapse:collapse; font-weight:700; padding:35px 0 0" align="center">
Changes to Your Meeting
</td>
</tr>
<tr>
<td style="color:#777; font-family:Helvetica, Arial, sans-serif; font-size:14px; line-height:21px; text-align:center; border-collapse:collapse; padding:10px 60px 0; width:100%" align="center" width="100%">
<p>Hi <?php echo Html::encode(MiscHelpers::getDisplayName($user_id)); ?>, changes have been made to your meeting.</p>
<p><?php echo $history; ?></p>
<p>Please click the button below to view the meeting page.</p>
</td>
</tr>
You can even see the result in the Preview tab—I had just processed the layout header in these screenshots:

Also, it sort of had to be all done together. I could have created an old and new layout and modified template code one by one, but that would have created more areas of changes. Ultimately, I had about seven full templates and their shared component pieces to process.
Because Meeting Planner's built within Yii2's MVC architecture, emails have an outer layout template and an inner template with a lot of intermingled PHP for data generation. I also had sub-templates for common, reusable elements such as meeting notes and footers.
You can't just process PHP-laden view code. You have to remove PHP elements, run the template through Premailer, and then reintegrate the PHP code. I'm fortunate that most of my PHP code doesn't heavily use the styles and was fairly simple to cut and later reintegrate.
Taken together, this made the process of generating inlined templates quite difficult and time-consuming. It also made the idea of maintaining and building new templates challenging.
Basically, I had to create temporary files with the entire style block above and the HTML that I wanted to inline below, remove the PHP, process the template, and then reintegrate the PHP.
I processed the Mail HTML layout first. Then, I processed each individual sub-template and template.
But it worked; here's a screenshot of the Reset Your Password template in web-based Gmail:

At some point near the end of all this grunt work and growing realization of how hard it would be to maintain my templates in the near future, I wondered if Mailgun provided CSS inlining and began to search online.
Mailgun did not, but SwiftMailer, which Yii uses for mail SMTP delivery, does. It took another half hour to clean up my earlier work (a.k.a. mess) and sort everything out, installing the CSS Inlining plugin for SwiftMailer.
I used the PHP-based Open Buildings CSS Inliner plugin which I added to composer.json:
"minimum-stability": "stable",
"require": {
"php": ">=5.4.0",
"yiisoft/yii2": ">=2.0.7",
"yiisoft/yii2-bootstrap": "*",
"yiisoft/yii2-swiftmailer": "*",
"openbuildings/swiftmailer-css-inliner":"*",
"2amigos/yii2-google-maps-library": "*",
Here's the composer update results:
$ composer update
Loading composer repositories with package information
Updating dependencies (including require-dev)
- Installing openbuildings/swiftmailer-css-inliner (0.3.0)
Downloading: 100%
- Installing symfony/css-selector (v3.1.0)
Downloading: 100%
- Installing tijsverkoyen/css-to-inline-styles (1.5.5)
Downloading: 100%
Writing lock file
Generating autoload filesI also needed to customize the mailer configuration to use the plugin within /common/config/main-local.php (in local and production):
],
'mailer' => [
'class' => 'yii\swiftmailer\Mailer',
'viewPath' => '@common/mail',
//comment the following array to send mail using php's mail function
'transport' => [
'class' => 'Swift_SmtpTransport',
'host' => 'smtp.mailgun.org',
'username' => 'xxxxxxxxxxxxxxxxxxxxxxxxxxxx',
'password' => 'xxxxxxxxxxxxxxxxxxxxxxxxxxxx',
'port' => '587',
'encryption' => 'tls',
'plugins' => [
[
'class' => 'Openbuildings\Swiftmailer\CssInlinerPlugin',
],
],
],
// send all mails to a file by default. You have to set
// 'useFileTransport' to false and configure a transport
// for the mailer to send real emails.
'useFileTransport' => false,
],
],Things began working pretty quickly, though there was still a major visual defect in Gmail:

The Open Building's CSS inliner written in PHP did not perform as successfully as the Python-based Premailer, at least out of the box with default settings.
Rather than spend time debugging the PHP-based inliner and the templates right now, I decided to switch back to the Premailer-processed templates. It works well for now.
At some point, I will need to revisit whether there are simple ways to fix this or to configure the PHP-based inlining plugin. Alternately, I may need to switch to the Python inliner.
When building a startup, you have to choose your battles and prioritize everything. At the moment, this is lower priority and fairly easy to work around.
In the code tree, you'll find /common/mail/inlining with a tree of various folders and a mail-readme.txt file to explain what's there. Basically, there are copies of the Oxygen templates, the working PHP versions, the edited pre-processed code, and the final processed code.
Currently, I'm working to prepare Meeting Planner for alpha release. I am primarily focused on improvements and features to make the alpha release go smoothly. I'm tracking everything in Asana now, which I'll write about in a future tutorial. There are also some interesting new features still on their way.
Finally, I'm beginning to experiment with WeFunder based on the implementation of the SEC's new crowdfunding rules. Please consider following our profile. I will also write more about this in a future tutorial.
While you're waiting for more episodes, schedule your first meeting and try out the templates with your friends with Gmail mailboxes. Also, I'd appreciate it if you share your experience below in the comments, and I'm always interested in your suggestions. You can also reach me on Twitter @reifman directly.
Watch for upcoming tutorials in the Building Your Startup With PHP series.
The Best Small Business Web Designs by DesignRush
/
2Create Modern Vue Apps Using Create-Vue and Vite
/
8Pros and Cons of Using WordPress
/
-5How to Fix the “There Has Been a Critical Error in Your Website” Error in WordPress
How To Fix The “There Has Been A Critical Error in Your Website” Error in WordPress
How to Create a Privacy Policy Page in WordPress
/
7WordPress Website Maintenance Guide For Beginners
/
8How Long Does It Take to Learn JavaScript?
/
-1How Long Does it Take to Learn JavaScript
/
1The Best Way to Deep Copy an Object in JavaScript
/
-2
4
-6Adding and Removing Elements From Arrays in JavaScript
/
-2Create a JavaScript AJAX Post Request: With and Without jQuery
/
85 Real-Life Uses for the JavaScript reduce() Method
/
-9How to Enable or Disable a Button With [removed] jQuery vs. Vanilla
/
2How to Enable or Disable a Button With [removed] jQuery vs Vanilla
/
-3Confirm Yes or No With JavaScript
/
-4How to Change the URL in [removed] Redirecting
/
-315+ Best WordPress Twitter Widgets
/
-227 Best Tab and Accordion Widget Plugins for WordPress (Free & Premium)
/
1121 Best Tab and Accordion Widget Plugins for WordPress (Free & Premium)
/
-1130 HTML Best Practices for Beginners
/
-731 Best WordPress Calendar Plugins and Widgets (With 5 Free Plugins)
/
525 Ridiculously Impressive HTML5 Canvas Experiments
/
-4
1How to Implement Email Verification for New Members
/
4How to Create a Simple Web-Based Chat Application
/
730 Popular WordPress User Interface Elements
/
-4Top 18 Best Practices for Writing Super Readable Code
/
2Best Affiliate WooCommerce Plugins Compared
/
-1018 Best WordPress Star Rating Plugins
/
1510+ Best WordPress Twitter Widgets
/
320+ Best WordPress Booking and Reservation Plugins
/
5Working With Tables in React: Part Two
/
-3Best CSS Animations and Effects on CodeCanyon
/
-1730 CSS Best Practices for Beginners
/
3How to Create a Custom WordPress Plugin From Scratch
/
310 Best Responsive HTML5 Sliders for Images and Text… and 3 Free Options
/
-516 Best Tab and Accordion Widget Plugins for WordPress
/
-518 Best WordPress Membership Plugins and 5 Free Plugins
/
525 Best WooCommerce Plugins for Products, Pricing, Payments and More
/
210 Best WordPress Twitter Widgets
1 /
1312 Best Contact Form PHP Scripts for 2020
/
-420 Popular WordPress User Interface Elements
/
-410 Best WordPress Star Rating Plugins
/
-412 Best CSS Animations on CodeCanyon
/
-112 Best WordPress Booking and Reservation Plugins
/
120 Best WordPress Calendar Plugins and Widgets
/
-212 Elegant CSS Pricing Tables for Your Latest Web Project
/
824 Best WordPress Form Plugins for 2020
/
-214 Best PHP Event Calendar and Booking Scripts
/
-1Getting Started With Django: Newly Updated Course
/
-1Create a Blog for Each Category or Department in Your WooCommerce Store
/
28 Best WordPress Booking and Reservation Plugins
/
-15Best Exit Popups for WordPress Compared
/
19Best Exit Popups for WordPress Compared
/
-411 Best Tab & Accordion WordPress Widgets & Plugins
/
-1112 Best Tab & Accordion WordPress Widgets & Plugins
1 /
3New Course: Practical React Fundamentals
/
2Short Course: Better Angular App Architecture With Modules
/
3Preview Our New Course on Angular Material
/
5Build Your Own CAPTCHA and Contact Form in PHP
/
-1Object-Oriented PHP With Classes and Objects
/
1Best Practices for ARIA Implementation
/
-5Accessible Apps: Barriers to Access and Getting Started With Accessibility
/
-3Dramatically Speed Up Your React Front-End App Using Lazy Loading
/
1815 Best Modern JavaScript Admin Templates for React, Angular, and Vue.js
/
-1515 Best Modern JavaScript Admin Templates for React, Angular and Vue.js
/
319 Best JavaScript Admin Templates for React, Angular, and Vue.js
/
3New Course: Build an App With JavaScript and the MEAN Stack
/
11Hands-on With ARIA: Accessibility Recipes for Web Apps
/
810 Best WordPress Facebook Widgets
13Hands-on With ARIA: Accessibility for eCommerce
/
6New eBooks Available for Subscribers
/
-10Hands-on With ARIA: Homepage Elements and Standard Navigation
/
10
-6Site Accessibility: Getting Started With ARIA
/
5How Secure Are Your JavaScript Open-Source Dependencies?
/
-4New Course: Secure Your WordPress Site With SSL
/
-3Testing Components in React Using Jest and Enzyme
/
-9Testing Components in React Using Jest: The Basics
/
-515 Best PHP Event Calendar and Booking Scripts
/
-2Create Interactive Gradient Animations Using Granim.js
/
9How to Build Complex, Large-Scale Vue.js Apps With Vuex
1Examples of Dependency Injection in PHP With Symfony Components
/
-5Set Up Routing in PHP Applications Using the Symfony Routing Component
1 /
9A Beginner’s Guide to Regular Expressions in JavaScript
/
9Introduction to Popmotion: Custom Animation Scrubber
/
-5Introduction to Popmotion: Pointers and Physics
/
-10New Course: Connect to a Database With Laravel’s Eloquent ORM
/
-5How to Create a Custom Settings Panel in WooCommerce
/
-14Building the DOM faster: speculative parsing, async, defer and preload
1 /
320 Useful PHP Scripts Available on CodeCanyon
3 /
51How to Find and Fix Poor Page Load Times With Raygun
/
1Introduction to the Stimulus Framework
/
-11Single-Page React Applications With the React-Router and React-Transition-Group Modules
/
1
712 Best Contact Form PHP Scripts
1 /
-3Getting Started With the Mojs Animation Library: The ShapeSwirl and Stagger Modules
/
1Getting Started With the Mojs Animation Library: The Shape Module
/
-3Getting Started With the Mojs Animation Library: The HTML Module
/
4Project Management Considerations for Your WordPress Project
/
-78 Things That Make Jest the Best React Testing Framework
/
3Creating an Image Editor Using CamanJS: Layers, Blend Modes, and Events
/
-1New Short Course: Code a Front-End App With GraphQL and React
/
2Creating an Image Editor Using CamanJS: Applying Basic Filters
/
-14Creating an Image Editor Using CamanJS: Creating Custom Filters and Blend Modes
/
-1Modern Web Scraping With BeautifulSoup and Selenium
/
1Challenge: Create a To-Do List in React
1 /
-1Deploy PHP Web Applications Using Laravel Forge
/
-2Getting Started With the Mojs Animation Library: The Burst Module
/
6
-1010 Things Men Can Do to Support Women in Tech
/
-3A Gentle Introduction to Higher-Order Components in React: Best Practices
/
-4Challenge: Build a React Component
/
-4A Gentle Introduction to HOC in React: Learn by Example
/
3A Gentle Introduction to Higher-Order Components in React
/
-6Creating Pretty Popup Messages Using SweetAlert2
/
5Creating Stylish and Responsive Progress Bars Using ProgressBar.js
/
1818 Best Contact Form PHP Scripts for 2022
/
-3How to Make a Real-Time Sports Application Using Node.js
/
-1Creating a Blogging App Using Angular & MongoDB: Delete Post
/
-15Creating a Blogging App Using Angular & MongoDB: Show Post
/
9Creating a Blogging App Using Angular & MongoDB: Home
/
8
4Creating a Blogging App Using Angular & MongoDB: Login
/
13Creating Your First Angular App: Implement Routing
/
13Persisted WordPress Admin Notices: Part 4
/
-3Creating Your First Angular App: Components, Part 2
/
4Persisted WordPress Admin Notices: Part 3
/
4
9Persisted WordPress Admin Notices: Part 2
/
-2Create Your First Angular App: Storing and Accessing Data
/
4Persisted WordPress Admin Notices: Part 1
/
-2Error and Performance Monitoring for Web & Mobile Apps Using Raygun
/
5Using Luxon for Date and Time in JavaScript
7 /
-7How to Create an Audio Oscillator With the Web Audio API
/
-5How to Cache Using Redis in Django Applications
/
220 Essential WordPress Utilities to Manage Your Site
/
-6Introduction to API Calls With React and Axios
/
16Beginner’s Guide to Angular 4: HTTP
/
12Rapid Web Deployment for Laravel With GitHub, Linode, and RunCloud.io
/
10Beginners Guide to Angular 4: Routing
/
-8Beginner’s Guide to Angular 4: Components
/
3Creating a Drop-Down Menu for Mobile Pages
/
6Introduction to Forms in Angular 4: Writing Custom Form Validators
/
4Getting Started With Redux: Connecting Redux With React
/
15Getting Started With Redux: Learn by Example
/
15Getting Started With Redux: Why Redux?
/
10Understanding Recursion With JavaScript
/
-2How to Auto Update WordPress Salts
/
-4How to Download Files in Python
/
-3
-21Eloquent Mutators and Accessors in Laravel
1 /
15
-10
1210 Best HTML5 Sliders for Images and Text
/
7Site Authentication in Node.js: User Signup
/
-3Creating a Task Manager App Using Ionic: Part 2
/
3Creating a Task Manager App Using Ionic: Part 1
/
2Introduction to Forms in Angular 4: Reactive Forms
/
2
4Introduction to Forms in Angular 4: Template-Driven Forms
/
224 Essential WordPress Utilities to Manage Your Site
/
-325 Essential WordPress Utilities to Manage Your Site
/
-11Get Rid of Bugs Quickly Using BugReplay
1 /
-16Manipulating HTML5 Canvas Using Konva: Part 1, Getting Started
/
610 Must-See Easy Digital Downloads Extensions for Your WordPress Site
/
-222 Best WordPress Booking and Reservation Plugins
/
-4Understanding ExpressJS Routing
/
-615 Best WordPress Star Rating Plugins
/
11Creating Your First Angular App: Basics
/
-1Inheritance and Extending Objects With JavaScript
/
-9Introduction to the CSS Grid Layout With Examples
1 /
4
6Performant Animations Using KUTE.js: Part 5, Easing Functions and Attributes
/
-9Performant Animations Using KUTE.js: Part 4, Animating Text
/
-13Performant Animations Using KUTE.js: Part 3, Animating SVG
/
-8New Course: Code a Quiz App With Vue.js
/
-1Performant Animations Using KUTE.js: Part 2, Animating CSS Properties
/
3
8Performant Animations Using KUTE.js: Part 1, Getting Started
/
110 Best Responsive HTML5 Sliders for Images and Text (Plus 3 Free Options)
/
-3Single-Page Applications With ngRoute and ngAnimate in AngularJS
/
-13Deferring Tasks in Laravel Using Queues
/
-5
2Site Authentication in Node.js: User Signup and Login
/
11Working With Tables in React, Part Two
/
-17Working With Tables in React, Part One
/
4How to Set Up a Scalable, E-Commerce-Ready WordPress Site Using ClusterCS
/
-4New Course on WordPress Conditional Tags
/
3
-14Building With Vue.js 2 and Firebase
6 /
14
-8Best Unique Bootstrap JavaScript Plugins
/
-9
-2Essential JavaScript Libraries and Frameworks You Should Know About
/
7
1Vue.js Crash Course: Create a Simple Blog Using Vue.js
/
-13Build a React App With a Laravel RESTful Back End: Part 1, Laravel 5.5 API
/
5API Authentication With Node.js
/
-4Beginner’s Guide to Angular: HTTP
/
7Beginner’s Guide to Angular: Routing
/
-4Beginners Guide to Angular: Routing
/
-4Beginner’s Guide to Angular: Services
/
3How to Create a Custom Authentication Guard in Laravel
/
6Learn Computer Science With [removed] Part 3, Loops
/
-5Build Web Applications Using Node.js
/
1Learn Computer Science With [removed] Part 4, Functions
/
4Learn Computer Science With [removed] Part 2, Conditionals
/
11Learn Computer Science With [removed] Part 1, The Basics
/
-2Create Interactive Charts Using Plotly.js, Part 5: Pie and Gauge Charts
/
-9Create Interactive Charts Using Plotly.js, Part 4: Bubble and Dot Charts
/
16Create Interactive Charts Using Plotly.js, Part 3: Bar Charts
/
-12Awesome JavaScript Libraries and Frameworks You Should Know About
/
-5Create Interactive Charts Using Plotly.js, Part 2: Line Charts
/
-8Bulk Import a CSV File Into MongoDB Using Mongoose With Node.js
/
-6Build a To-Do API With Node, Express, and MongoDB
/
-7Getting Started With End-to-End Testing in Angular Using Protractor
/
9TypeScript for Beginners, Part 4: Classes
/
-17Object-Oriented Programming With JavaScript
/
510 Best Affiliate WooCommerce Plugins Compared
/
6Stateful vs. Stateless Functional Components in React
/
8Make Your JavaScript Code Robust With Flow
/
-3Build a To-Do API With Node and Restify
/
6Testing Components in Angular Using Jasmine: Part 2, Services
/
1Testing Components in Angular Using Jasmine: Part 1
/
1Creating a Blogging App Using React, Part 6: Tags
/
-10React Crash Course for Beginners, Part 3
/
4React Crash Course for Beginners, Part 2
/
8React Crash Course for Beginners, Part 1
/
2Set Up a React Environment, Part 4
1 /
10Set Up a React Environment, Part 3
/
-11New Course: Get Started With Phoenix
/
-9Set Up a React Environment, Part 2
/
1Command Line Basics and Useful Tricks With the Terminal
/
4How to Create a Real-Time Feed Using Phoenix and React
/
-4Build a React App With a Laravel Back End: Part 2, React
/
3Build a React App With a Laravel RESTful Back End: Part 1, Laravel 9 API
/
-5Creating a Blogging App Using React, Part 5: Profile Page
/
-1Pagination in CodeIgniter: The Complete Guide
/
21JavaScript-Based Animations Using Anime.js, Part 4: Callbacks, Easings, and SVG
JavaScript-Based Animations Using Anime.js, Part 3: Values, Timeline, and Playback
/
-1Learn to Code With [removed] Part 1, The Basics
/
410 Elegant CSS Pricing Tables for Your Latest Web Project
/
-8Getting Started With the Flux Architecture in React
/
-2Getting Started With Matter.js: The Composites and Composite Modules
/
2Getting Started With Matter.js: The Engine and World Modules
/
1610 More Popular HTML5 Projects for You to Use and Study
/
-23Understand the Basics of Laravel Middleware
/
-3Iterating Fast With Django & Heroku
/
8Creating a Blogging App Using React, Part 4: Update & Delete Posts
/
4Creating a jQuery Plugin for Long Shadow Design
/
-11How to Register & Use Laravel Service Providers
2 /
-13Unit Testing in React: Shallow vs. Static Testing
/
4Creating a Blogging App Using React, Part 3: Add & Display Post
/
15Creating a Blogging App Using React, Part 2: User Sign-Up
20 /
-3Creating a Blogging App Using React, Part 1: User Sign-In
/
79 More Popular HTML5 Projects for You to Use and Study
/
16Creating a Grocery List Manager Using Angular, Part 2: Managing Items
/
89 Elegant CSS Pricing Tables for Your Latest Web Project
/
-1Dynamic Page Templates in WordPress, Part 3
/
-2Angular vs. React: 7 Key Features Compared
/
6Creating a Grocery List Manager Using Angular, Part 1: Add & Display Items
/
2New eBooks Available for Subscribers in June 2017
/
6Create Interactive Charts Using Plotly.js, Part 1: Getting Started
/
10The 5 Best IDEs for WordPress Development (And Why)
/
-133 Popular WordPress User Interface Elements
/
2New Course: How to Hack Your Own App
/
-11How to Install Yii on Windows or a Mac
/
4What Is a JavaScript Operator?
/
-6How to Register and Use Laravel Service Providers
/
8
waly Good blog post. I absolutely love this…