Sendune

Sendune began as an in-house template builder for an email platform before its creators extracted the editor into a standalone open-source project. Rather than compiling layouts through intermediate engines like MJML, the tool outputs raw, client-tested HTML directly. The result is a self-contained designer that produces clean email markup for any delivery service.

Why Sendune instead of Mailchimp

Mailchimp binds template editing to an all-in-one marketing silo with subscriber databases and mandatory sending rails. Small teams and agencies that already have established outbound pipelines often find themselves paying Mailchimp's per-contact tiers simply so non-technical staff can use a drag-and-drop newsletter builder. Sendune isolates the design step: operators compose responsive layouts in a browser interface, export clean HTML, and route it through whatever transactional provider—such as SendGrid or Resend—their stack already uses.

The workflow difference also affects portability. Mailchimp stores templates in vendor-specific formats that resist easy migration. Sendune relies on standard email markup derived from proven cross-client conventions, ensuring exported messages render predictably in Outlook, Apple Mail, and Gmail without external CSS dependencies. You do trade away Mailchimp's contact segmenting, automated journeys, and native analytics dashboards, requiring your team to manage audience data elsewhere. For agencies handling client-owned delivery accounts or ops teams embedding a template canvas into an internal portal, that separation of authoring from delivery is a welcome operational trade-off.

What it does well

• Three editing modes: teams can assemble layouts with visual drag-and-drop blocks, edit raw HTML in an integrated Monaco editor, or compose plain-text messages.
• Clean HTML output without intermediate compilation steps like MJML, generating email tables and inline styles that work across all major clients.
• Embeddable Angular component (@send-with-ses/ng-email-designer), allowing engineering teams to mount the canvas inside client dashboards or internal portals.
• Pluggable storage callbacks that connect image uploads directly to Amazon S3, Cloudflare R2, or Google Cloud Storage buckets.
• Configurable theme variables and CSS overrides that align the editor toolbar and canvas with an agency style guide.