01 A clear top-down growth strategy Typically enterprise bulk sms service service companies start out serving mid-sized businesses and then quickly decide to go big. But HubSpot didn't do that because we felt SMEs were underserved and didn't have really good tools to help them grow. Expand customer base . HubSpot's growth platform market is large, and existing vendors are particularly underserved for SMBs and often lack sufficient resources to implement complex solutions. Our growth platform can help SMBs efficiently carry out inbound marketing to help them bulk sms service achieve better growth. We will also continue to develop this business. Increase revenue for existing customers. With 73,483 clients from multiple industries in over 120 countries, HubSpot has a great opportunity to grow revenue from existing clients. We plan to develop additional new products, as well as expand our customers' use of the growth platform by cross-selling to existing customers, thereby increasing the revenue of existing customers.
Continue to expand internationally . Outside bulk sms service the U.S., there is a big opportunity for the HubSpot growth platform. As of December 31, 2019, approximately 45% of HubSpot's total customers were located outside the United States, and these customers generated approximately 40% of total revenue in 2019 alone. We intend to increase our investment in local sales, marketing and professional services capabilities, as well as expand our presence in bulk sms service international markets by leveraging a network of solution partners. Continue to innovate and expand growth platforms. SMBs are increasingly realizing the value of having an integrated marketing, sales and customer service platform. We will expand the capabilities of our growth platform by introducing new products and applications.
For example, in 2019, HubSpot added email and bulk sms service advertising to its free CRM, launching new integrations. Selective acquisitions. In 2019, HubSpot acquired PieSync, and we will plan to selectively acquire complementary businesses, technologies and teams, adding features and capabilities to our growth platform, and accelerating the pace of our innovation. 02 Product-led growth approach As HubSpot expands more rapidly internationally, we created a bulk sms service freemium model to help bring products to market faster. The freemium model also allows customers to try the software for free and get value from our software before paying for it. This freemium model, arguably the way forward in B2B software, has proven to be a very good decision. Through this model, our potential customers (or registered customers) have been greatly improved. 1. Launching new products is an important part of growth Whereas most marketers focus on ac