maildev / maildev

:mailbox: SMTP Server + Web Interface for viewing and testing emails during development.

axllent / mailpit

An email and SMTP testing tool with API for developers

rnwood / smtp4dev

smtp4dev - the fake smtp email server for development and testing

ChangemakerStudios / Papercut-SMTP

Papercut SMTP -- The Simple Desktop Email Server

inbucket / inbucket

Disposable webmail server (similar to Mailinator) with built in SMTP, POP3, RESTful servers; no DB required.

postfixadmin / postfixadmin

PostfixAdmin - web based virtual user administration interface for Postfix mail servers

goshs-labs / goshs

Feature-rich single-binary file server for red teamers and developers. HTTP/S · WebDAV · FTP/SFTP · SMB · LDAP/S · NTLM hash capture · DNS/SMTP callbacks · TLS · Auth · Share links. A powerful python3 -m http.server replacement.

nodemailer / smtp-server

Create custom SMTP servers on the fly

bokysan / docker-postfix

Multi architecture simple SMTP server (postfix null relay) host for your Docker and Kubernetes containers. Based on Debian/Ubuntu/Alpine.

decke / smtprelay

Simple Golang SMTP relay/proxy server

KumoCorp / kumomta

The first Open-Source high-performance MTA developed from the ground-up for high-volume email sending environments.

truespar / sentio

Email inbox API for AI agents. Give every agent its own real email address, receive mail as structured webhooks, and reply in-thread over REST. A complete multi-tenant mail server in Rust: inbound and outbound, DKIM/SPF/DMARC/ARC, MTA-STS, DANE, three-tier anti-spam.