Open-source Netcore Cloud alternatives

Postal is a complete mail server for websites and web servers that handles both outgoing and incoming email. The project describes it as an open-source take on services such as Sendgrid, Mailgun and Postmark, ready to run on your own servers rather than rented as a hosted API.

It is written in Ruby and released under the MIT license. The project provides documentation with installation instructions, an FAQ and features list, a separate repository of installation tools, and community support through GitHub Discussions and Discord. Repository topics list Ruby, mail, SMTP and mail server.

Because it is self-hosted, Postal suits teams that want control over their own email delivery infrastructure instead of relying on a hosted provider, such as websites that send transactional messages.

Mautic is open-source marketing automation software. It lets businesses and organizations build integrated marketing campaigns, including email marketing, while keeping control of their own data. The project is supported by a worldwide community of contributors and presents privacy and extensibility as core goals.

The README highlights several advantages over conventional hosted tools: it is free to use, you can run it on your own infrastructure with your own database, there is no vendor lock-in, integrations can be built as needed, and both the frontend and backend are customizable. It also describes multi-channel marketing without extra cost and unlimited segmentation and automation.

Mautic is written in PHP. It can be downloaded and self-hosted, or you can request a trial of a hosted option, and community channels and a blog share news, releases and strategy. Its license is stated in the repository. It suits marketing teams that want automation without relying entirely on a third-party SaaS provider.

Plunk is an open-source email platform that combines transactional email, marketing campaigns and workflow automation in a single product. Developers can send messages from an API with templates and variable substitution, or use Plunk as an SMTP relay so that existing tools and frameworks can send through it.

Marketing features include campaigns for newsletters and product updates, dynamic segments, and contact management with custom fields and activity history. Workflows add triggers, delays and conditional logic, analytics track opens, clicks and bounces, custom domains are verified with DKIM and SPF, and inbound emails can be received and routed with custom rules.

Plunk is positioned as an open-source, self-hosted alternative to services such as SendGrid, Resend and Mailgun. It is licensed under AGPL-3.0, written in TypeScript, and can be deployed from an official Docker image following the project's documentation. The README cites a rate of $0.001 per email with no contact limits.

Notifuse is a modern, self-hosted emailing platform for sending newsletters and transactional email at a fraction of the cost of hosted services. It is built with Go and React and presented as an open-source alternative to Mailchimp, Brevo, Mailjet, Listmonk, MailerLite, and Klaviyo. The input lists its license only as other.

Email marketing features include a drag-and-drop visual builder with MJML components and live preview, campaign scheduling, A/B testing of subject lines, content, and send times, list segmentation, and contact profiles with custom fields. Automations use a visual canvas with nodes for delays, emails, branches, filters, list changes, A/B tests, and webhooks, and Liquid templating personalizes messages. Messages are sent through seven providers, with topics naming Amazon SES, Mailgun, Postmark, and SendGrid.

For people who prefer not to run it themselves, Notifuse Cloud offers managed hosting, which the README says starts at 16 dollars per month, and a live demo is available. It suits marketers and developers who want lower costs and control over subscriber data.

Laudspeaker is an open-source customer engagement and product onboarding platform. It was positioned as an alternative to tools such as Braze, OneSignal, Customer.io, Appcues and Pendo, and lets teams design product onboarding flows and send messages triggered by product events across several channels.

Its main features were a visual journey builder for complex workflows, a segment builder that targets users by attributes, completed actions and previous campaigns, multiple channels including push, email, SMS and webhooks, and A/B tests and personalization with Liquid templating and external API calls. It was built with NestJS, React and TypeScript, and planned to integrate with data warehouses and the modern data stack.

The README now states that Laudspeaker is no longer under active development or being supported. It mentions a Laudspeaker Cloud and a paid self-deployed enterprise plan, though availability is uncertain given that notice. The repository lists its licence as other. Anyone considering it should treat it as an archived project and check current status before building on it.

Dittofeed is an omni-channel customer engagement platform. Teams use it to send one-off broadcasts or build automated, event-driven user journeys that reach people by email, mobile push notifications, SMS, WhatsApp, Slack and other channels. The project positions itself as a developer-friendly, open-source alternative to OneSignal, Customer.io and Segment Engage.

A typical setup starts by connecting user data through Segment, reverse ETL or the Dittofeed API. You then build segments with multiple operators, design message templates in HTML, MJML or a low-code editor, and send through providers such as SendGrid or Amazon SES. A dashboard tracks message performance, and the tools can be embedded in another product through an iframe or a headless React component.

The core is written in TypeScript and licensed under MIT. It can be self-hosted with Docker Compose or deployed to Render, and a hosted cloud trial is also offered. According to the README, features such as multi-tenancy, embedding and white-labeling belong to a separate licensed, closed-source codebase that you can ask the team about.