
Sam Seely is the co-founder and CEO of Knock, a New York-based notification infrastructure company that turned the tedious plumbing of transactional email, push, SMS and in-app messages into an API and workflow engine used by Vercel, Amplitude and others. He and CTO Chris Bell, who met at Frame.io, launched Knock in 2021 and raised a $12M Series A led by Craft Ventures in February 2024, bringing total funding to $18M.
Velt is a San Francisco developer-tools startup that ships a full-stack SDK and APIs letting product teams embed contextual comments, notifications, presence, async recordings, huddles, and CRDT-based multiplayer editing directly inside their apps in days rather than months. Founded in 2020 by ex-Google product manager Rakesh Goyal and part of Y Combinator's W22 batch, Velt has evolved from a general collaboration toolkit into a review-and-approval layer where AI and humans review work together and nothing ships until a human approves. It is developer-first, enterprise-ready (SOC 2 Type II, HIPAA), and used by companies including Google, Pendo, HeyGen, and LambdaTest.
Courier is a San Francisco notification infrastructure platform that lets developers add multi-channel messaging - email, SMS, push, in-app, Slack and more - to their apps through a single API and a drag-and-drop designer. Often described as 'Stripe for notifications,' it routes messages intelligently across channels so engineering teams stop rebuilding notification systems from scratch. Founded in 2019 (YC S19), Courier raised a $35M Series B led by GV in 2022 and powers notifications for companies like New Relic, LaunchDarkly, Lattice, Vanta and Contentful.
Thomas Schiavone is a San Francisco startup operator who has spent his career on the bottoms-up, developer-first side of software. He was the first product manager at Twilio (around employee #15), went on to be COO at EasyPost and VP of Product at Sift, advised at Netlify, then founded and ran the SaaS CRM startup Calixa. He now leads Courier, the developer-first notifications platform that lets engineering teams design and deliver email, SMS, push, and chat through one API.