ActiveSync

ActiveSync
Name	ActiveSync
Developer	Microsoft
Released	1996
Latest release version	Proprietary
Operating system	Windows CE, Windows Mobile, Windows Phone, iOS, Android
Genre	Data synchronization protocol
License	Proprietary / Licensed implementations

ActiveSync. ActiveSync is a proprietary data synchronization protocol and service technology developed by Microsoft for synchronizing mail, contacts, calendar, and tasks between mobile devices and Microsoft server products. It integrates with a range of client platforms and server products and has influenced standards and alternate implementations across the technology industry.

Overview

ActiveSync was created by Microsoft to enable real-time synchronization between server-side messaging systems and mobile clients such as devices running Windows CE, Windows Mobile, Windows Phone, iOS, and Android. The protocol coordinates data between server products including Microsoft Exchange Server, Microsoft 365 services, and hosted mailbox providers. It competes with and complements standards and products from vendors such as Google, Apple, IBM, Oracle, and Amazon and interacts with enterprise systems maintained by organizations like Accenture, Deloitte, and Capgemini.

History and Development

Microsoft began developing mobile synchronization technologies in the 1990s alongside projects such as Windows CE and Pocket PC, later formalizing ActiveSync to integrate with Microsoft Exchange Server and Outlook. Over time, development intersected with milestones and entities including the launch of Windows Mobile, the introduction of Windows Phone, shifts prompted by Apple’s iPhone, the growth of Android from Google, and enterprise adoption driven by firms like Samsung and Nokia. Industry events and agreements—including standards work at the Internet Engineering Task Force, interoperability efforts with vendors such as BlackBerry, and acquisitions by Microsoft like the purchase of Skype—shaped its evolution. Corporate customers such as IBM, Hewlett-Packard, Cisco, and VMware influenced enterprise features, while regulatory landscapes involving bodies like the European Commission, the United States Department of Justice, and data protection authorities informed deployment practices.

Protocol and Architecture

ActiveSync operates over HTTP/HTTPS and uses a combination of MIME, XML, and binary encodings in its remote procedure and synchronization operations. Architecturally, it hinges on client-server exchanges with command sets for folder synchronization, item synchronization, and settings management, and it interplays with mail stores such as Microsoft Exchange databases managed by technologies from companies like Redmond’s server teams. The protocol has been analyzed and reimplemented by independent projects and vendors including Zarafa, Zimbra, Scalix, and open-source communities influenced by foundations and corporations such as Apache, Linux Foundation, Canonical, and Red Hat. Interoperability testing and certification efforts involve organizations like IETF working groups and consortiums including the OASIS membership base.

Features and Functionality

ActiveSync supports bidirectional synchronization of email, calendar, contacts, tasks, notes, and policies, including push email, remote wipe, policy enforcement, and partial item retrieval for bandwidth optimization. Features were adapted to integrate mobile device management stacks used by VMware Workspace ONE, MobileIron, Citrix, and Microsoft Intune, and to support enterprise identity systems from Okta, Ping Identity, Microsoft Azure Active Directory, and on-premises LDAP deployments. Client experiences were shaped by device makers and platform vendors such as Samsung Knox, HTC, Sony, LG, Motorola, and OEM partners collaborating with Microsoft’s Windows Mobile and Windows Phone teams.

Security and Privacy

ActiveSync incorporates transport security via TLS/SSL sessions negotiated with certificate authorities such as DigiCert, GlobalSign, Entrust, Let's Encrypt, and industry PKI systems. Policy controls support enforcement of passcodes, encryption of device storage, selective wipe, and conditional access integrated with directory services like Microsoft Active Directory and Azure AD. Security researchers and firms—Symantec, McAfee, Kaspersky, FireEye, CrowdStrike—and audits by consultancies such as PwC, EY, and KPMG have examined deployment hardening and threat models, while privacy considerations have been addressed in compliance frameworks overseen by regulators including the Information Commissioner’s Office, CNIL, and national data protection authorities.

Implementations and Client Support

Microsoft ships native ActiveSync support in Exchange Server, Exchange Online, and Outlook; client support has appeared in native mobile mail clients on Windows Mobile, Windows Phone, iOS Mail, and Android mail apps and third-party clients by vendors such as Qualcomm, Broadcom, Intel, Samsung, and HTC. Server-side and gateway implementations have been produced by companies including AetherPal, Good Technology, Zimbra, Kerio, Scalix, and DavMail, and cloud providers like Google Cloud Platform, Amazon Web Services, and Azure host services that interoperate with ActiveSync deployments. Interoperability labs and partner ecosystems involve major integrators and manufacturers such as Dell, HP, Lenovo, Fujitsu, Ericsson, Nokia, Motorola Solutions, and Huawei.

Legacy, Deprecation, and Alternatives

As mobile ecosystems evolved, Microsoft shifted toward Exchange ActiveSync protocol versions and modern APIs including Exchange Web Services and Microsoft Graph, and many organizations migrated clients to protocols and platforms from Google, Apple, and open standards like IMAP, CalDAV, and CardDAV. Alternatives and successors involve cloud APIs from Microsoft Graph, REST interfaces promoted by Google Calendar and Apple Calendar, synchronization services from Box, Dropbox, Box.com integrations, and enterprise mobility management suites from Microsoft, VMware, Citrix, and Google. The transition influenced migrations undertaken by enterprises such as banks, healthcare providers, universities, and government agencies, with migrations often planned in coordination with consultants from Accenture, Deloitte, EY, PwC, and KPMG.

Category:Microsoft software