transactional-email
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Campaign Monitor and the art of waiting ten years
Two Australian designers built the email tool their clients needed, then waited a decade to take outside money. Campaign Monitor by Marigold still sells a deceptively useful idea: good marketing should be easier to make.
Courier
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.
Brevo
Brevo (formerly Sendinblue) is a Paris-based all-in-one customer engagement platform serving 500,000+ businesses across 180 countries. The platform combines email marketing, SMS, CRM, live chat, and marketing automation under one roof — all priced by email volume rather than contact count. Founded in 2012 by Armand Thiberge, Brevo rebranded from Sendinblue in 2023 to reflect its evolution from an email tool into a full customer lifecycle platform. In December 2025 it achieved unicorn status after raising €500 million in a Series C round led by General Atlantic and Oakley Capital, with a valuation exceeding €1 billion.