Go SDK

Send email with Chi

Use Parcel Wing from Chi routes while keeping the API key server-side.

Install the SDK

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

Terminal

go get github.com/parcelwing/parcelwing-go

Chi route

Create the Parcel Wing client during server startup, then reuse it from trusted server-side handlers.

main.go

package main
 
import (
    "encoding/json"
    "net/http"
    "os"
 
    "github.com/go-chi/chi/v5"
    parcelwing "github.com/parcelwing/parcelwing-go"
)
 
func main() {
    client, err := parcelwing.New(os.Getenv("PARCELWING_API_KEY"))
    if err != nil {
        panic(err)
    }
 
    r := chi.NewRouter()
    r.Post("/send-welcome", func(w http.ResponseWriter, r *http.Request) {
        var payload map[string]string
        if err := json.NewDecoder(r.Body).Decode(&payload); err != nil {
            http.Error(w, "invalid json", http.StatusBadRequest)
            return
        }
 
        emails, err := client.Emails.Send(r.Context(), parcelwing.EmailSendRequest{
            From:          os.Getenv("PARCELWING_FROM_EMAIL"),
            To:            payload["email"],
            TemplateAlias: "welcome",
            TemplateParams: map[string]any{"first_name": payload["first_name"]},
        })
        if err != nil {
            http.Error(w, err.Error(), http.StatusBadGateway)
            return
        }
 
        w.Header().Set("content-type", "application/json")
        json.NewEncoder(w).Encode(map[string]any{"id": emails[0].ID})
    })
 
    http.ListenAndServe(":8080", r)
}

Production notes

Keep PARCELWING_API_KEY in server-side environment variables.
Use the incoming request context where available so sends can respect request cancellation.
Log structured *parcelwing.Error fields for support and debugging.