Open Source AutoSend Alternatives

Plunk puts transactional email, marketing campaigns and workflow automation in one self-hosted platform, so a product team stops paying for and stitching together a separate sender, newsletter tool and automation service. It positions itself against SendGrid, Resend and Mailgun.

Mail leaves through the API with template support and variable substitution, or through Plunk acting as an SMTP relay, which lets any existing tool or framework send through it without code changes.

Beyond sending, the platform manages the audience and the reporting.

• Campaigns: send newsletters and product updates to large audiences.
• Workflows: build automations with triggers, delays and conditional logic.
• Segments: filter contacts dynamically to reach the right audience.
• Contact management: keep custom fields and a full activity history per contact.
• Analytics: track opens, clicks, bounces and engagement in real time.
• Inbound email: receive incoming messages and route them with custom rules.

Custom domains are verified with DKIM and SPF so mail goes out under your own name. The easiest deployment is the official Docker image, with a full guide in the documentation, and the code is licensed AGPL-3.0. The project advertises a cost of $0.001 per email and no contact limits, which suits teams mailing long lists.

useSend is sending infrastructure you host yourself. Like most email products it uses Amazon SES underneath, and adds the dashboard, contact management and subscription handling that SES alone leaves you to build.

The stack is Next.js with Prisma, Tailwind and shadcn/ui, authentication through NextAuth.js, tRPC for the internal API and Hono for the public one, and Redis for the sending queue. The email editor is built on tiptap, converts its output to HTML with jsx-email, and takes its cues from maily.to.

The current release covers transactional and marketing sending alike.

• Domains: add and verify the domains you send from.
• Transactional mail: a REST API plus SMTP support for applications that already speak it.
• Marketing email: bulk sends such as newsletters and product updates, with subscriptions handled for you.
• Scheduling and webhooks: a schedule API for future sends, and webhooks for delivery events.
• Dashboard: delivered, opened, clicked and bounced figures in one view.

Inbound email and bring-your-own AWS credentials are listed but not yet built, and the project describes itself as being in beta while it opens up for public testing. Docker images are published on Docker Hub and the GitHub Container Registry, needing environment variables for the database, Redis and AWS, and a Railway template is the quickest way to stand an instance up.

Notifuse sends newsletters and transactional email from infrastructure you control, positioning itself against Mailchimp, Brevo, Klaviyo and their peers. What it removes is the per email bill and the copy of your contact list living in someone else's database.

The backend is Go, arranged in domain, service, repository and HTTP layers, with PostgreSQL as the only datastore. The admin console is React, TypeScript and Ant Design, and an embeddable notification center widget ships beside it. Delivery goes out through a provider you connect, with Amazon SES, Mailgun, Postmark, Mailjet, SparkPost, SendGrid and plain SMTP supported.

The platform reaches well past broadcast sending.

• Visual builder: drag and drop editing on MJML components with real-time preview.
• Automations: multi-step journeys built as a graph of delay, branch, filter, webhook and A/B test nodes.
• Liquid templating: drop contact fields into subject lines and bodies.
• Web analytics: cookieless traffic measurement with engaged time sessions and channel attribution, all on PostgreSQL.
• Transactional API: trigger mail from your own code over REST and receive events by webhook.
• Workspaces: keep separate tenants for teams or agency clients.

Deployment is a Docker image with an interactive setup wizard, and the web analytics side needs PostgreSQL 17 or newer. The project does not accept pull requests, though issues are welcome, and version 40.0 onward carries a Business Source License 1.1 that converts to AGPL-3.0 four years after each release, while version 39 and everything earlier stays AGPL permanently. Five capabilities require a license key and the send path contains no license check.