Ruby

# No additional dependencies required for basic usage

# .env
KEPLERS_API_KEY=kms_your_api_key.live_...

require 'net/http'
require 'json'
require 'uri'

class KeplersEmailClient
  def initialize(api_key, base_url = 'https://api.keplars.com')
    @api_key = api_key
    @base_url = base_url
  end

  def send_email(email_data)
    make_request('/api/v1/send-email/queue', email_data)
  end

  def send_instant_email(email_data)
    make_request('/api/v1/send-email/instant', email_data)
  end

  private

  def make_request(endpoint, data)
    uri = URI("#{@base_url}#{endpoint}")
    
    http = Net::HTTP.new(uri.host, uri.port)
    http.use_ssl = true
    
    request = Net::HTTP::Post.new(uri)
    request['Authorization'] = "Bearer #{@api_key}"
    request['Content-Type'] = 'application/json'
    request.body = data.to_json
    
    response = http.request(request)
    
    if response.code == '200'
      JSON.parse(response.body)
    else
      raise "Failed to send email: #{response.body}"
    end
  end
end

client = KeplersEmailClient.new(ENV['KEPLERS_API_KEY'])

def send_welcome_email(client, user_email, user_name)
  begin
    email_data = {
      to: [user_email],
      subject: "Welcome #{user_name}!",
      body: "<h1>Welcome #{user_name}!</h1><p>Thank you for joining our platform.</p>",
      is_html: true
    }
    
    result = client.send_email(email_data)
    puts "Email sent: #{result}"
    result
  rescue => e
    puts "Failed to send email: #{e.message}"
    raise
  end
end

def send_verification_email(client, user_email, code)
  begin
    email_data = {
      to: [user_email],
      subject: 'Verify Your Email',
      body: "Your verification code: #{code}",
      is_html: false
    }
    
    result = client.send_instant_email(email_data)
    puts "Verification email sent: #{result}"
    result
  rescue => e
    puts "Failed to send verification email: #{e.message}"
    raise
  end
end

send_welcome_email(client, '[email protected]', 'John')
send_verification_email(client, '[email protected]', '123456')

# app/services/email_service.rb
class EmailService
  def self.client
    @client ||= KeplersEmailClient.new(Rails.application.credentials.keplers_api_key)
  end

  def self.send_welcome_email(email, name)
    email_data = {
      to: [email],
      subject: "Welcome #{name}!",
      body: "<h1>Welcome #{name}!</h1>",
      is_html: true
    }
    
    client.send_email(email_data)
  end
end

# app/controllers/auth_controller.rb
class AuthController < ApplicationController
  def register
    begin
      EmailService.send_welcome_email(params[:email], params[:name])
      render json: { success: true }
    rescue => e
      render json: { error: 'Failed to send email' }, status: 500
    end
  end
end

require 'sinatra'
require 'json'

configure do
  set :keplers_client, KeplersEmailClient.new(ENV['KEPLERS_API_KEY'])
end

post '/send-email' do
  content_type :json
  
  data = JSON.parse(request.body.read)
  
  begin
    email_data = {
      to: [data['email']],
      subject: "Welcome #{data['name']}!",
      body: "<h1>Welcome #{data['name']}!</h1>",
      is_html: true
    }
    
    result = settings.keplers_client.send_email(email_data)
    { success: true, data: result }.to_json
  rescue => e
    status 500
    { success: false, error: e.message }.to_json
  end
end

# Gemfile
gem 'mail'
gem 'net-smtp'

require 'mail'

class KeplersEmailSMTPClient
  def initialize(smtp_config)
    @config = smtp_config
    configure_mail
  end

  def send_email(email_data)
    mail = Mail.new do
      from     '[email protected]'
      to       email_data[:to].first
      subject  email_data[:subject]
      
      if email_data[:is_html]
        html_part do
          content_type 'text/html; charset=UTF-8'
          body email_data[:body]
        end
      else
        text_part do
          content_type 'text/plain; charset=UTF-8'
          body email_data[:body]
        end
      end
    end

    mail.deliver!
    { success: true, data: { status: 'sent', method: 'smtp' } }
  rescue => e
    raise "SMTP send failed: #{e.message}"
  end

  private

  def configure_mail
    Mail.defaults do
      delivery_method :smtp, {
        address: 'smtp.keplars.com',
        port: 587,
        user_name: @config[:username],
        password: @config[:password],
        authentication: 'plain',
        enable_starttls_auto: true
      }
    end
  end
end

smtp_client = KeplersEmailSMTPClient.new({
  username: ENV['KEPLERS_SMTP_USERNAME'],
  password: ENV['KEPLERS_SMTP_PASSWORD']
})

def send_email_via_smtp(smtp_client, user_email, subject, body)
  begin
    email_data = {
      to: [user_email],
      subject: subject,
      body: body,
      is_html: true
    }
    
    result = smtp_client.send_email(email_data)
    puts "SMTP email sent: #{result}"
    result
  rescue => e
    puts "SMTP send failed: #{e.message}"
    raise
  end
end

send_email_via_smtp(smtp_client, '[email protected]', 'Test Email', '<p>Hello World!</p>')