https://github.com/gzuidhof/myrtle
Modern emails for Go
https://github.com/gzuidhof/myrtle
email go golang
Last synced: 9 days ago
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Modern emails for Go
- Host: GitHub
- URL: https://github.com/gzuidhof/myrtle
- Owner: gzuidhof
- License: mit
- Created: 2026-02-20T16:16:01.000Z (4 months ago)
- Default Branch: main
- Last Pushed: 2026-03-12T11:48:11.000Z (4 months ago)
- Last Synced: 2026-03-28T13:35:28.628Z (3 months ago)
- Topics: email, go, golang
- Language: Go
- Homepage:
- Size: 3.33 MB
- Stars: 26
- Watchers: 0
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
# 🌸 myrtle
Myrtle is a composable, strongly typed email content builder for Go.
| Default | Terminal |
| --- | --- |
|  |  |
## Features
- Fluent builder pattern for email content.
- Strongly typed library of blocks.
- Modern built-in themes: `default`, `flat`, `terminal`, `editorial`.
- Built-in advanced blocks such as tables, charts, grids.
- High-impact blocks: timelines, standout stats rows, badges, attachments.
- Dual rendering APIs:
- `HTML()` for final HTML output.
- `Text()` for plain-text fallback output.
- Customizable and extensible: bring your own theme, styles or custom blocks.
- Left-to-right and right-to-left direction support (e.g. for Arabic/Hebrew).
- Renders OK in Outlook Classic and other notoriously difficult email clients.
- Dependency-free aside from [`goldmark`](https://github.com/yuin/goldmark) for Markdown rendering.
## Installation
```bash
go get github.com/gzuidhof/myrtle
```
## Quick start (security email)
```go
package main
import (
"github.com/gzuidhof/myrtle"
defaulttheme "github.com/gzuidhof/myrtle/theme/default"
)
func main() {
email := myrtle.NewBuilder(defaulttheme.New()).
WithPreheader("Use this one-time code to sign in").
AddHeading("Your verification code").
AddText("Use the code below to complete your sign-in. This code expires in 10 minutes.").
AddVerificationCode("Verification code", "493817").
AddKeyValue("Request details", []myrtle.KeyValuePair{
{Key: "IP", Value: "203.0.113.5"},
{Key: "Location", Value: "Amsterdam, NL"},
}).
AddText("If you did not request this code, secure your account immediately.").
AddButton("Review account", "https://example.com/account/security").
Build()
html, err := email.HTML()
if err != nil {
panic(err)
}
md, err := email.Text()
if err != nil {
panic(err)
}
// Use your favorite e-mail sending library to send the email with the generated HTML and text content.
// ...
_ = html
_ = md
}
```
Make use of auto-complete/Intellisense in your IDE to explore the rich library of blocks and customization options.
## Expandable snippets
Custom block (basic)
```go
package main
import (
"fmt"
"github.com/gzuidhof/myrtle"
"github.com/gzuidhof/myrtle/theme"
defaulttheme "github.com/gzuidhof/myrtle/theme/default"
)
type DeploymentStatus struct {
Service string
Version string
Status string
}
func main() {
block := myrtle.NewCustomBlock(
theme.BlockKind("deployment_status"),
DeploymentStatus{Service: "billing-api", Version: "v1.42.0", Status: "healthy"},
func(v DeploymentStatus, values theme.Values) (string, error) {
_ = values
return fmt.Sprintf("
%s on %s: %s
", v.Service, v.Version, v.Status), nil
},
func(v DeploymentStatus, context myrtle.RenderContext) (string, error) {
_ = context
return fmt.Sprintf("%s on %s: %s", v.Service, v.Version, v.Status), nil
},
)
email := myrtle.NewBuilder(defaulttheme.New()).
AddHeading("Deployment update").
Add(block).
Build()
_, _ = email.HTML()
_, _ = email.Text()
}
```
Style tweaks (basic)
```go
package main
import (
"github.com/gzuidhof/myrtle"
"github.com/gzuidhof/myrtle/theme"
defaulttheme "github.com/gzuidhof/myrtle/theme/default"
)
func main() {
styles := theme.DefaultDarkModeStyles()
styles.ColorPrimary = "#22d3ee"
styles.MaxWidthMain = "640px"
styles.MainContentBodyTopSpacing = "0"
email := myrtle.NewBuilder(
defaulttheme.New(),
myrtle.WithStyles(styles),
).
WithPreheader("Theme overrides example").
AddHeading("Style tweaks").
AddText("This message uses a dark preset with a few token overrides.").
AddButton("Open dashboard", "https://example.com/dashboard").
Build()
_, _ = email.HTML()
_, _ = email.Text()
}
```
Concurrent rendering with shared header/footer/theme/styles
```go
package main
import (
"sync"
"github.com/gzuidhof/myrtle"
"github.com/gzuidhof/myrtle/theme"
defaulttheme "github.com/gzuidhof/myrtle/theme/default"
)
type RenderedEmail struct {
To string
HTML string
Text string
Err error
}
func main() {
// Shared theme/styles/header/footer used to build one baseline builder.
sharedStyles := theme.Styles{
ColorPrimary: "#2563eb",
MaxWidthMain: "640px",
}
sharedHeader := myrtle.NewGroup().
AddImage("https://example.com/logo.png", "Myrtle", myrtle.ImageWidth(120), myrtle.ImageAlign(myrtle.ImageAlignmentCenter)).
AddText("Security updates", myrtle.TextAlign(myrtle.TextAlignCenter), myrtle.TextWeight(myrtle.TextWeightSemibold))
sharedFooter := myrtle.NewGroup().
AddLegal(
"Myrtle Inc.",
"Dam Square 1, 1012 JS Amsterdam, Netherlands",
"https://example.com/preferences",
"https://example.com/unsubscribe",
)
baseBuilder := myrtle.NewBuilder(defaulttheme.New(), myrtle.WithStyles(sharedStyles)).
WithHeader(sharedHeader).
WithFooter(sharedFooter).
WithPreheader("Important account security update")
recipients := []string{"ana@example.com", "bo@example.com", "cy@example.com"}
results := make([]RenderedEmail, len(recipients))
var wg sync.WaitGroup
for i, to := range recipients {
wg.Add(1)
go func(i int, to string) {
defer wg.Done()
// Clone the baseline builder and apply recipient-specific content.
email := baseBuilder.Clone().
AddHeading("Account alert").
AddText("We detected a sign-in from a new location.").
AddKeyValue("Recipient", []myrtle.KeyValuePair{{Key: "Email", Value: to}}).
AddButton("Review activity", "https://example.com/security").
Build()
html, err := email.HTML()
if err != nil {
results[i] = RenderedEmail{To: to, Err: err}
return
}
text, err := email.Text()
results[i] = RenderedEmail{To: to, HTML: html, Text: text, Err: err}
}(i, to)
}
wg.Wait()
_ = results
}
```
## Examples
- [example/weekly_operations_brief.go](example/high_impact.go)
- [example/account_deletion_confirmation.go](example/account_deletion_confirmation.go)
- [example/security.go](example/security.go)
- [example/monster.go](example/monster.go)
### Rendered examples
#### Weekly operations brief
| Default | Flat |
| --- | --- |
|  |  |
| Terminal | Editorial |
|  |  |
#### Account deletion confirmation
| Default | Flat |
| --- | --- |
|  |  |
| Terminal | Editorial |
|  |  |
#### Security confirmation
| Default | Flat |
| --- | --- |
|  |  |
| Terminal | Editorial |
|  |  |
#### Monster
The monster example is a fun showcase of many blocks and styles together. It intentionally has a lot of content to demonstrate how the builder and themes handle it.
- [example/screenshot/default--monster.png](example/screenshot/default--monster.png)
## Example server
The [example/server](example/server) package serves a directory of all example emails and block previews.
Clone this repository and run the server to preview example emails in the browser at `http://localhost:8380/`.
```bash
go run ./example/server/cmd
```
## Development
The code for this repository is repetitive and verbose, I recommend you use AI-assisted code generation to speed up development. Writing inlined CSS manually is particularly painful.
This library is not stable yet, your layouts will likely shift a bit with future releases.
## License
Myrtle is licensed under the MIT License. See [LICENSE](LICENSE) for more information.
> Myrtle she wrote.