go get github.com/teamredevs/mailofly-go@latest

package main

import (
	"os"

	"github.com/teamredevs/mailofly-go"
)

func main() {
	client, err := mailofly.New(mailofly.Options{
		APIKey: os.Getenv("MAILOFLY_API_KEY"),
		// BaseURL: "https://www.mailofly.com", // optional
	})
	if err != nil {
		panic(err)
	}
	_ = client
}

result, err := client.Emails.Send(map[string]any{
	"from":    "Acme <onboarding@example.com>",
	"to":      []string{"alex@example.com"},
	"subject": "Hello",
	"html":    "<p>Thanks for signing up.</p>",
})
if err != nil {
	if apiErr, ok := err.(*mailofly.Error); ok {
		fmt.Println(apiErr.Status, apiErr.Err, apiErr.DetailMessage)
	}
	panic(err)
}
_ = result

client.Emails.Send(map[string]any{
	"from": "Acme <onboarding@example.com>",
	"to":   []string{"alex@example.com"},
	"template": map[string]any{
		"id":        "uuid-of-template",
		"variables": map[string]any{"first_name": "Alex"},
	},
})

result, err := client.Batch.Send([]map[string]any{
	{
		"from":    "Acme <onboarding@example.com>",
		"to":      []string{"foo@example.com"},
		"subject": "hello world",
		"html":    "<h1>it works!</h1>",
	},
	{
		"from":    "Acme <onboarding@example.com>",
		"to":      []string{"bar@example.com"},
		"subject": "world hello",
		"html":    "<p>it works!</p>",
	},
})

accounts, _ := client.Accounts.List()

client.Contacts.Create(map[string]any{
	"email":          "alex@example.com",
	"first_name":     "Alex",
	"custom_fields":  map[string]any{"plan": "pro"},
})

client.Campaigns.Send("campaign-uuid", map[string]any{"send_now": true})

logs, _ := client.MailLogs.List(&mailofly.MailLogsListOptions{
	Status:   "failed",
	Page:     1,
	PageSize: 50,
})
_ = accounts
_ = logs

meta, err := mailofly.Discovery("")
if err != nil {
	panic(err)
}
fmt.Println(meta)

if apiErr, ok := err.(*mailofly.Error); ok {
	fmt.Println(apiErr.Status, apiErr.Err, apiErr.DetailMessage)
}