1.novuhq / novuThe open-source communication infrastructure for agents and productsnotificationscommunicationemailsmspush-notificationstransactional+9 moreTypeScriptOther license40K total4.5K forks+971 starsfrom 39,320 · score 6.88
2.gotify / serverA simple server for sending and receiving messages in real-time per WebSocket. (Includes a sleek web-ui)golangnotificationsapireactjavascriptgotify+7 moreGoOther license16K total900 forks+580 starsfrom 15,601 · score 6.36
3.Notifuse / notifuseOpen-source, self-hosted newsletter, email marketing and transactional email platform. Visual MJML editor, Liquid templating, 7 sending providers.mailing-listnewsletterself-hostedamazon-sesbulk-emailcampaign-management+14 moreGoOther license2.3K total242 forks+248 starsfrom 2,025 · score 5.52
4.nodemailer / nodemailer✉️ Send e-mails with Node.JS – easy as cake!nodemaileremailemail-senderrfc822TypeScriptOther license18K total1.4K forks+109 starsfrom 17,595 · score 4.70