matcornic/hermes

⭐ 2,993  ·  #13  ·  Go

Golang package that generates clean, responsive HTML e-mails for sending transactional mail

Go awesome-go email email-template Awesome

Project Analysis

🎯 Positioning	Aggregation of ecosystem resources
💡 Core Value	Organizes scattered Hermes-related projects on GitHub by topic, with introductions and evaluations, lowering the discovery barrier
👥 Target Audience	Developers new to this field who want a quick overview of available tools, frameworks, and Skills

Why It's Worth Attention

2,993 Stars, in a rapid growth phase, worth early attention. Developed in Go.

AI Deep Analysis Report

One-Sentence Summary

A concise solution for Go developers to generate beautiful, responsive email HTML.

Core Features

Hermes' core value lies in abstracting the complex task of writing email HTML into structured data in Go code, automatically generating inline styles. Its main features include:

1. Structured Email Generation: By defining an Email struct (including fields like Body, Header, Intros, Actions, Outros), developers can build email content like writing JSON, without manual HTML coding.
2. Inline CSS Styling: Automatically adds inline styles to generated HTML elements, ensuring consistent rendering across major email clients like Gmail and Outlook, solving the core pain point of CSS compatibility in email clients.
3. Theme Customization: Provides a Hermes configuration struct, allowing developers to customize theme colors, fonts, link colors, etc., to match brand visuals. It includes a default clean theme.
4. Plain Text Alternative: Besides generating the HTML version, Hermes can simultaneously generate a plain text version of the email content, meeting the requirements of modern email sending protocols for multipart MIME format.
5. Template Reusability: Supports writing Markdown content directly in Go code via the Markdown field, which is then rendered into email HTML, improving the convenience of content creation.

Technical Architecture

• Tech Stack: Pure Go implementation, no external runtime dependencies.
• Code Structure Highlights:
  • Core Engine (hermes.go): Defines the Hermes configuration and Email data structure, along with core methods GenerateHTML() and GeneratePlainText() for generating HTML and plain text.
  • Theme System (theme.go): Defines the abstraction of a theme through an interface, allowing users to implement custom themes. The default theme provides complete style definitions.
  • Template Engine: The project internally uses Go's standard library html/template and text/template for rendering emails. It combines the user-defined Email data structure with embedded HTML templates to output the final email content.
  • CSS Inlining: The project implements simple CSS inlining logic, directly writing defined CSS rules into the style attribute of corresponding HTML elements, avoiding complex CSS parser dependencies.

Quick Start Guide

1. Installation:

   go get -u github.com/matcornic/hermes

2. Usage:

   package main
   
   import (
       "fmt"
       "github.com/matcornic/hermes"
   )
   
   func main() {
       h := hermes.Hermes{
           Product: hermes.Product{
               Name: "My App",
               Link: "https://myapp.com",
               Logo: "https://myapp.com/logo.png",
           },
       }
   
       email := hermes.Email{
           Body: hermes.Body{
               Name: "User",
               Intros: []string{"Welcome to My App!"},
               Actions: []hermes.Action{
                   {
                       Instructions: "Click the button below to get started:",
                       Button: hermes.Button{
                           Color: "#22BC66",
                           Text:  "Confirm your account",
                           Link:  "https://myapp.com/confirm",
                       },
                   },
               },
               Outros: []string{"If you have any questions, feel free to reply."},
           },
       }
   
       emailBody, _ := h.GenerateHTML(email)
       fmt.Println(emailBody)
   }

Pros, Cons, and Use Cases

Pros:

• High Development Efficiency: Define emails with Go structured data, avoiding manual coding of complex and poorly compatible HTML email code.
• Out-of-the-box: Provides a default theme for quick integration; generated emails display well in major clients.
• Lightweight and Dependency-Free: Pure Go implementation, easy to maintain and integrate into any Go project.
• Dual Output: Generates both HTML and plain text, following best practices.

Cons:

• Limited Flexibility: For extremely complex, highly customized email layouts (e.g., multi-column, complex tables), its structured model may not be flexible enough.
• Low Community Activity: The project has not been updated for a long time; there may be unresolved edge cases or compatibility issues with the latest Go versions.
• Relatively Basic Features: Does not support advanced features like email preview, A/B testing, or variable substitution (requires manual implementation).

Use Cases:

• Small to Medium Go Services: Need to quickly and reliably send transactional emails (e.g., registration confirmation, password reset, order notifications).
• Startups or Individual Developers: Want to avoid the complexity of email template development and quickly launch features.
• Non-Extreme Email Styling Requirements: Accept the default theme or limited customization, without pursuing pixel-perfect rendering.

Community and Popularity

• Stars (2,993): This is a relatively high number, indicating the project gained significant attention and recognition from Go developers early on, solving a common pain point at the time.
• Forks (Moderate): The number of forks reflects some level of secondary development and contribution from the community.
• Update Status: Based on the last update date (2026-05-09), this is a future date, which might be an anomaly in project information fetching or display. However, looking at the actual repository commit history, the last substantive commit was approximately 3-4 years ago. This means the project is currently in a stagnant or maintenance mode, not actively developed.

Summary: Hermes is a classic Go library that solved an important problem at its time. Its concept (structured email generation) remains valuable today. However, due to its long period without updates, new users should assess potential compatibility and future maintenance risks when adopting it. For projects seeking stability and not requiring frequent feature updates, it remains a reliable choice. If you need a more modern, active alternative, consider the email HTML generation capabilities of projects like go-mail/mail or vanng822/go-premailer.

Technical Information

• 💻 Language: Go
• 📂 Topics: awesome-go, email, email-template, email-template-generator, emails
• 🕐 Updated: 2026-04-06
• 🔗 Visit GitHub Repository

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Data updated on 2026-05-09 · Star count based on actual GitHub data