How do I ignore certain CSS styles when inlining with PreMailer.Net?

Use the ignoreElements parameter with a CSS selector, such as '#ignore', to exclude specific style blocks. For example, add id='ignore' to style tags containing media queries you want to preserve, as shown in the README examples.

Does PreMailer.Net work with .NET Core and newer versions?

Yes, it's compatible with .NET Core and .NET 5+, as indicated by the .NET Core build badge and NuGet package. Check the GitHub actions for current build status and updates.

PreMailer.Net vs MJML for email templates?

PreMailer.Net is a C# library for CSS inlining in existing HTML, while MJML is a markup language for building responsive emails from scratch. Use PreMailer if you have custom HTML templates in .NET; MJML is better for design-focused workflows.

How to add Google Analytics tracking to emails with PreMailer.Net?

Call the AddAnalyticsTags method on a PreMailer instance, providing parameters like source and campaign. This appends UTM parameters to links, and you can optionally limit it to a specific domain for targeted tracking.

Can PreMailer.Net handle CSS from external URLs or CDNs?

Yes, it supports downloading external CSS files from absolute or relative URLs, as long as the href ends with .css. Use the baseUri parameter for relative paths to ensure proper fetching.

What are common warnings in PreMailer.Net and how to fix them?

Warnings often include unsupported pseudo-classes. Review the Warnings collection in InlineResult and adjust your CSS to use inline-compatible properties, or ignore problematic selectors using the ignoreElements option.

Open-Awesome

PreMailer.Net

MITC#v2.7.2

A C# library that moves CSS stylesheets to inline style attributes for maximum email client compatibility.

Visit Website GitHub

686 stars117 forks0 contributors

What is PreMailer.Net?

PreMailer.Net is a C# library that converts CSS styles in HTML email templates into inline style attributes. It solves the problem of inconsistent CSS support across email clients by ensuring styles are applied directly to HTML elements, improving rendering reliability.

Target Audience

C# developers building email marketing systems, transactional email services, or any application that generates HTML emails requiring consistent cross-client compatibility.

Value Proposition

Developers choose PreMailer.Net for its robust handling of email-specific CSS quirks, built-in analytics tagging, and flexible options like media query preservation, all within a familiar .NET ecosystem.

Overview

C# library that moves your stylesheets to inline style attributes, for maximum compatibility with E-mail clients.

Use Cases

Best For

Converting HTML email templates with external CSS to inline styles
Ensuring consistent rendering across Gmail, Outlook, and other email clients
Adding UTM tracking parameters to links in marketing emails
Preserving responsive media queries while inlining other CSS
Processing email templates in .NET-based web applications
Automating email styling workflows in C# backend systems

Not Ideal For

Applications built on non-.NET stacks like Node.js or Python
High-throughput email services where minimal processing latency is critical
Teams needing integrated email client testing or preview tools beyond CSS inlining

Pros & Cons

Pros

Comprehensive CSS Inlining

Converts both external and internal CSS to inline styles, ensuring maximum email client compatibility as described in the README, which is critical for reliable rendering across clients like Outlook and Gmail.

Media Query Preservation

Allows selective preservation of media queries for responsive emails via the ignoreElements or preserveMediaQueries options, enabling mobile-friendly designs without inlining all styles.

Built-in Analytics Tagging

Includes AddAnalyticsTags method to automatically append UTM parameters to links, simplifying campaign tracking for marketing emails without manual URL editing.

Flexible DOM Access

Provides Document property for custom HTML manipulation using AngleSharp before inlining, useful for advanced scenarios like preprocessing or conditional styling.

Cons

External Dependency Risks

Relies on third-party libraries like AngleSharp for HTML parsing, which can introduce compatibility issues or breaking changes with updates, as noted in the dependency handling.

Performance Overhead

Processing involves downloading external CSS and DOM manipulation, which may add latency for large or complex templates, especially in high-volume email generation systems.

Limited Pseudo-Class Support

Unsupported pseudo-classes and elements are ignored and logged as warnings, requiring manual checks to avoid styling gaps, as admitted in the README's notes section.

Frequently Asked Questions

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