Bulk create/delete shipping rates in the Shopify backend. Go to Settings/Shipping and paste it into Javascript console. WARNING: This is a proof of concept, use with extreme caution and only if you know what you're doing, you will have to customize this to fit your needs. Again, just a proof of concept, worked for me, might not work for you. Ong…

bulk import shipping rates

function make_shipping_rates(id, low, mid, high) {
  $.post('/admin/price_based_shipping_rates.json', {
    price_based_shipping_rate: {
      country_id: id, 
      min_order_subtotal: "0",
      max_order_subtotal: "500",
      name: "DHL Premiumversand", 
      offsets: [], 
      price: low
    }
  });
  $.post('/admin/price_based_shipping_rates.json', {
    price_based_shipping_rate: {
      country_id: id, 
      min_order_subtotal: "500",
      max_order_subtotal: "2500",
      name: "DHL Premiumversand", 
      offsets: [], 
      price: mid
    }
  });
  $.post('/admin/price_based_shipping_rates.json', {
    price_based_shipping_rate: {
      country_id: id, 
      min_order_subtotal: "2500",
      max_order_subtotal: "25000",
      name: "DHL Premiumversand", 
      offsets: [], 
      price: high
    }
  });
}

function remove_weight_based_shipping_rates(country) {
  $.each(country.weight_based_shipping_rates, function(j,item) {
    $.ajax({
      url: '/admin/weight_based_shipping_rates/' + item.id + '.json',
      type: 'DELETE',
      success: function(){
        console.log(item.name + ' deleted!');
      }
    });
  });
}

function remove_price_based_shipping_rates(country) {
  $.each(country.price_based_shipping_rates, function(j,item) {
    $.ajax({
      url: '/admin/price_based_shipping_rates/' + item.id + '.json',
      type: 'DELETE',
      success: function(){
        console.log(item.name + ' deleted!');
      }
    });
  });
}

$.get('/admin/countries.json', function(countries){
  $.each(countries.countries, function(i, country) {
    // remove_weight_based_shipping_rates(country);
    // remove_price_based_shipping_rates(country);
    var north_america = ['US', 'CA', 'MX'];
    if( $.inArray(country.code, north_america) != -1 ) {
      make_shipping_rates(country.id, 40, 50, 90);
    } else if (country.code == 'DE') {
      make_shipping_rates(country.id, 7, 10, 20);
    } else if (country.code == '*') {
      make_shipping_rates(country.id, 40, 50, 90);
    } else  {
      make_shipping_rates(country.id, 15, 25, 65);
    }
  });
});