SendGrid is a Denver, Colorado-based transactional email delivery and management service. The company was founded by Isaac Saldana, Jose Lopez, and Tim Jenkins in 2009, and incubated through the TechStars accelerator program. As of 2013, SendGrid has raised over $27 million and has offices in Denver, Boulder, Orange, California, and London, and operations in New York City and San Francisco. SendGrid provides a cloud-based email delivery service that assists businesses with email delivery. The service manages various types of email including shipping notifications, friend requests, sign-up confirmations, and email newsletters. It also handles internet service provider (ISP) monitoring, domain keys, sender policy framework (SPF), and feedback loops. Additionally, the company provides link tracking, open rate reporting. It also allows companies to track email opens, unsubscribes, bounces, and spam reports. Beginning in 2012, the company integrated SMS, voice, and push notification abilities to its service through a partnership with Twilio. SendGrid offers a freemium version and a Lite Plan (pay-as-you-go), as well as three expanded levels of service: Essentials, Pro, and Premier.