Alterable
Email content rendered when it's opened, not when it's sent
Alterable is a dynamic email content platform. Drop one image tag into your template and the picture is rendered when each subscriber opens the email: the countdown shows the real time left, the map points at their nearest store, the offer matches their weather, the product pick is theirs. Nothing changes in your ESP, so it works with Klaviyo, HubSpot, Mailchimp or anything that sends HTML email.
Six services: countdown timers, dynamic images, dynamic products, local maps, one-click surveys and scratch-and-win cards, plus a rules engine that targets by device, location, weather and time. Only opened emails count. The Engage plan is free forever: 10,000 impressions a month, no credit card.