Go SDK

Send email with Go

Install the official Parcel Wing Go SDK, configure a server-side API key, and send your first transactional email.

Requirements

Go 1.22 or newer.
A Parcel Wing API key stored as PARCELWING_API_KEY.
A verified sending domain for your from address.

Install the SDK

The official Go SDK is published as github.com/parcelwing/parcelwing-go.

Terminal

go get github.com/parcelwing/parcelwing-go

Send your first email

Create a parcelwing.Client and call client.Emails.Send.

main.go

package main
 
import (
    "context"
    "fmt"
    "log"
    "os"
 
    parcelwing "github.com/parcelwing/parcelwing-go"
)
 
func main() {
    client, err := parcelwing.New(os.Getenv("PARCELWING_API_KEY"))
    if err != nil {
        log.Fatal(err)
    }
 
    emails, err := client.Emails.Send(context.Background(), parcelwing.EmailSendRequest{
        From:    "Acme <[email protected]>",
        To:      "[email protected]",
        Subject: "Hello from Parcel Wing",
        HTML:    "<strong>It works!</strong>",
        Text:    "It works.",
    })
    if err != nil {
        log.Fatal(err)
    }
 
    fmt.Println(emails[0].ID)
}

Configuration

Set a custom base URL or headers when testing locally or tagging traffic from your app.

client.go

client, err := parcelwing.New(
    os.Getenv("PARCELWING_API_KEY"),
    parcelwing.WithBaseURL(os.Getenv("PARCELWING_BASE_URL")),
    parcelwing.WithHeader("X-App-Name", "acme-go-app"),
)

Send to multiple recipients

To accepts either a single email string or a slice of email strings.

bulk.go

emails, err := client.Emails.Send(ctx, parcelwing.EmailSendRequest{
    From:    "Acme <[email protected]>",
    To:      []string{"[email protected]", "[email protected]"},
    Subject: "Hello from Parcel Wing",
    Text:    "It works!",
})

Use a template

Use TemplateAlias and TemplateParams for reusable lifecycle messages.

templates.go

emails, err := client.Emails.Send(ctx, parcelwing.EmailSendRequest{
    From:          "Acme <[email protected]>",
    To:            "[email protected]",
    TemplateAlias: "welcome",
    TemplateParams: map[string]any{
        "first_name": "Ada",
        "plan":       "Launch",
    },
})

Handle errors

API and transport failures are returned as *parcelwing.Error.

errors.go

emails, err := client.Emails.Send(ctx, request)
if err != nil {
    if pwErr, ok := err.(*parcelwing.Error); ok {
        log.Printf("status=%d type=%s code=%s message=%s", pwErr.Status, pwErr.Type, pwErr.Code, pwErr.Message)
        return
    }
 
    log.Fatal(err)
}
_ = emails

Framework guides

net/http

Use Parcel Wing from a net/http application with server-side API key handling.

Gin

Use Parcel Wing from a Gin application with server-side API key handling.

Echo

Use Parcel Wing from a Echo application with server-side API key handling.

Fiber

Use Parcel Wing from a Fiber application with server-side API key handling.

Chi

Use Parcel Wing from a Chi application with server-side API key handling.

Gorilla/mux

Use Parcel Wing from a Gorilla/mux application with server-side API key handling.