Haraka
Haraka can serve thousands of concurrent connections and deliver thousands of messages per second. Haraka and plugins are written in asynchronous JS and are very fast. Haraka has very good spam protection (see plugins) and works well as a filtering MTA. It also works well as an MSA running on port 587 with auth and dkim_sign plugins enabled. Haraka makes no attempt to be a mail store (like an exchange or postfix/exim/qmail), an LDA, or an IMAP server (like Dovecot or courier). Haraka is typically used with such systems. Haraka has a scalable outbound mail delivery engine built in. Mail marked as relaying (such as via an auth plugin) is automatically queued for outbound delivery. Haraka's plugin architecture provides an easily extensible MTA that complements traditional MTAs that excel at managing mail stores but do not have sufficient filtering.
Learn more
Aid4Mail
Aid4Mail is a fast, reliable, and highly accurate tool to collect, recover, search, and convert emails. It supports most mailbox file formats (e.g. PST, OST, OLM, mbox), IMAP accounts (e.g. Yahoo! Mail, AOL) and popular mail service providers (e.g. Microsoft 365, Exchange, Gmail). Aid4Mail can recover double-deleted messages and corrupted emails, and extract MIME data from certain types of unknown file formats through file carving.
Aid4Mail provides a large array of tools to search and filter out unwanted emails during conversion. Save time by using native pre-acquisition filters to download a subset of your mail from Exchange, Office 365, Gmail and other webmail services. Use Aid4Mail’s integrated search engine to cull-down your email collection. Its search operators are very similar to Gmail and Office 365.
Aid4Mail is used by Fortune 500 companies, government agencies and legal professionals around the world. It is made in Switzerland by perfectionists.
Learn more
Hermes SEG
Hermes SEG is a free, open-source secure email gateway and server. It delivers spam, virus, and malware protection using SpamAssassin, ClamAV, and Amavisd-new, along with full encryption in transit and at rest via SMTP TLS, S/MIME, PGP, encrypted PDF (CipherMail), and Dovecot mail-crypt. It includes email archiving and integrated mailbox hosting with quotas, aliases, shared folders, Sieve rules, vacation replies, and mobile auto-configuration. Collaboration features come through Nextcloud (webmail, file sync, calendars, contacts). Identity and access are managed with OpenLDAP and Authelia, supporting SSO and MFA (TOTP, WebAuthn, Duo). It also enforces modern authentication standards: SPF, DKIM, DMARC, and ARC.
Learn more
Kopano
We provide you with your digitally sovereign solution to keep track of your e-mails and calendars, to organize yourself with tasks or to stay in contact with team colleagues via video meeting. Kopano Groupware is an e-mail and calendaring solution, which can be operated digitally sovereign. Its functionality is comparable to that of Microsoft Outlook and Exchange. Kopano Groupware installations can be operated with more than 100,000 users. Kopano Groupware is an e-mail and calendar server that provides users with their daily communication and organizational data on all devices and connects teams. Data can be jointly edited in public folders or shared with others from your own inbox.
Learn more
