Top 18 Email Software SaaS Companies in May 2026

Guildford, England, United Kingdom

For over 20 years, Symprex has been focusing on building software solutions for Microsoft Office and Exchange. Since 2006, we have been one of the globally leading providers of email signature solutions for Office 365, Microsoft 365, and Exchange Server. From our headquarters just outside of London, Symprex services over 10,000 customers in 100+ countries across all industries and public services with some customers holding licenses for over 50,000 users. Our latest offering, Signature 365, is a completely cloud-based email signature solution entirely managed via the Signature 365 portal and works with all email clients and devices. The Signature 365 add-in available for Outlook is a world first, offering all the same features in Outlook for Windows, Outlook for Mac, and Outlook on the Web, and is easily deployed directly from the customer's Microsoft 365 admin center. Symprex works in close partnership with Microsoft and is a Microsoft Partner since 2002.

Moscow, Russia

Operator of an independent software vendor designed to develop the next generation out- of-the-box enterprise mobility service. The company's software vendor operations provides a mobile workplace for smartphones and tablets with features like electronic messaging via corporate mail, secure access to corporate file depots and folders stored on office PCs, document editing, direct file or screen broadcasting for presentations and meetings, enabling organizations and employees to increase productivity with the help of increased software mobility services.

St. Petersburg, Florida, United States

Mimestream is building the next generation of email and communication tools. Our first product is a native macOS email client for Gmail – try it free at https://mimestream.com!

Helsinki, Finland

Workki AI assistant can help you with email writing, scheduling events, working with documents, copywriting, and data analysis (charts, tables). Powered by GPT-4 and Assembly AI (voice input), and integrates with both Outlook and Google. Get more office work done in less time. This AI productivity tool revolutionizes the work in the office. Soon it will be a platform that can host teams and allow them to work on the same projects together.

Palo Alto, California, United States

Developer of self-hostable web productivity suite designed to make open source and indie Web applications viable as an ecosystem. The company's self-hostable web productivity suite offers personal cloud platform which install applications like e-mail, document editors, blogging software using a simple app-store-like interface, enabling individuals, developers and enterprises to install and run arbitrary software on servers they control.

United States

ZimaOne.com is a cloud based business suite made for the 200 million small and midsized businesses, offering a complete solution to manage your entire business in the cloud. From e-mail, to calendaring, to financials and invoicing, a business only have one login to manage everything in the cloud.

Afghanistan

MailDeck provides Microsoft 365 Outlook, Google Workspace, and Private SMTP inboxes for cold email outreach. 650K+ managed inboxes for 1,500+ B2B clients with zero shared IPs, automated DNS setup, and pricing from $0.30/inbox