What is SendGrid?

What is SendGrid?

SendGrid came out of Techstars Boulder in 2009, founded by Isaac Saldana, Jose Lopez and Tim Jenkins after Saldana had rebuilt the same bounce handling, reputation management and unsubscribe plumbing at one startup after another. It listed on the NYSE in November 2017, the first Techstars company to reach an IPO, and Twilio bought it in an all-stock deal worth roughly $3 billion that closed on 1 February 2019. Since February 2026 the brand has been folded into Twilio.com, and sendgrid.com URLs redirect there.

What you get is sending infrastructure, not a marketing tool. A message goes in through the v3 REST endpoint or through an authenticated SMTP relay using the API key as the password, which is why legacy applications that only speak SMTP can move across with a config change and no code. Around that sit shared and dedicated IP pools, warmup scheduling, domain authentication, and an Event Webhook that POSTs every delivery, open, click, bounce and spam report back to your own endpoint. Glassdoor, Nextdoor, Strava and Shopify all send through it.

One thing most write-ups still get wrong: the free plan is gone. Twilio ended it on 27 May 2025 after a 60-day wind-down that permanently deleted stored contacts above 100. What is left is a 60-day trial at 100 emails a day, which makes SendGrid a materially different proposition from the one described in most older comparisons.