avalara_example.rb

require 'avalara'

Avalara.username = "user@example.com"
Avalara.password = 'pass'
Avalara.endpoint = 'https://development.avalara.net' # this is the test url, in production use https://rest.avalara.net

invoice     = Avalara::Request::Invoice.new(customer_code: 'customer@example.com')
origin      = Avalara::Request::Address.new(address_code: 1, line1: '1600 Amphitheatre Pkwy', city: 'Mountain View', region: 'CA', country: 'USA', postal_code: '94043')
destination = Avalara::Request::Address.new(address_code: 2, line1: '1 Infinite Loop', city: 'Cupertino', region: 'CA', country: 'USA', postal_code: '95014')
line        = Avalara::Request::Line.new(line_no: 1, destination_code: 2, origin_code: 1, item_code: 'X123', description: 'T-Shirt', qty: 1, amount: 9.99)


invoice.addresses = [origin, destination]
invoice.lines = [line]

response = Avalara.get_tax(invoice)

total_tax = response.tax_lines.inject(0) {|sum, line| sum + line.tax.to_f }