eBuddy is a privately held Dutch software company that offers instant messaging services. eBuddy is a pioneer in the mobile messaging landscape with its services having 400 million users; 300 million downloads; and 650 billion messages processed. The company's flagship service is XMS, a proprietary cross-platform instant messaging service. After a successful partnership with Japanese-based GREE, eBuddy was sold via an aqui-hire to Booking.com. Up until that point the company was backed by Prime Technology Ventures and Lowland Capital Partners and headquartered in Amsterdam, Netherlands, and had offices in Singapore and San Francisco, USA. The company is now owned by the co-founders Onno Bakker & Jan-Joost Rueb, who have regained control over the eBuddy software, know-how, patents and trademarks.
XMS is a proprietary cross platform instant messaging service. At one point, XMS was processing over 17 billion messages a month exchanged between more than 30 million unique users - 100,000 users were signing up daily and 1.5 billion banner ads sold on web. In a 2011 review, the head of the BerryReview team mentioned that the service has many features in common with other cross-platform messaging services. It does include some multimedia features: users can send images and videos, and can share their location. XMS is available for iOS, Android, BlackBerry, Nokia Series 40, and Windows Phone 7 devices. There is also a web-based client, called "Web XMS", for computer users.
On November 4, 2014, Ebuddy XMS scored 1 out of 7 points on the Electronic Frontier Foundation's secure messaging scorecard. Ebuddy XMS received a point for encryption during transit but lost points because communications are not encrypted with a key the provider doesn't have access to (i.e. the communications are not end-to-end encrypted), users can't verify contacts' identities, past messages are not secure if the encryption keys are stolen (i.e. the service does not provide forward secrecy), the code is not open to independent review (i.e. the code is not open-source), the security design is not properly documented, and there has not been a recent independent security audit. AIM, BlackBerry Messenger, Hushmail, Kik Messenger, Skype, Viber, and Yahoo Messenger also scored 1 out of 7 points.
eBuddy Chat was a line of multi-protocol instant messaging clients: it allowed users with Facebook Chat, MSN, Google Talk, Yahoo Messenger, ICQ and AOL accounts to chat free of charge in one aggregated interface. eBuddy Chat supported a Web interface and also supported iOS, Android, J2ME and mobile Web-enabled devices. In 2010, it was named one of the five finalists for “Best Mobile App” in the Mashable Awards.
eBuddy was originally developed by Paulo Taylor. His idea was established as a consequence from a bet to develop MSN Messenger, as it was named in 2003, for a mobile phone. After several weeks he won the bet, and uploaded the application to a server. A web version was soon developed following users' demands. As user traffic spurred, Taylor decided to take the idea further.
- On September 9, 2003, Taylor, together with two partners Jan-Joost Rueb and Onno Bakker, created EverywhereMSN.com.
- On June 1, 2006, e-Messenger was renamed to eBuddy.
- On October 26, 2006, eBuddy received $6.33M (€5M) in Series A funding.
- On May 2, 2008 eBuddy received $9.55M (€6.5M) in Series B funding.
- On March 17, 2011, eBuddy launched its proprietary instant messaging app XMS.
- On September 21, 2012, Japanese gaming company GREE acquired a minority stake in eBuddy.
- However, GREE decided to leave the European market in 2013.
- On December 4, 2013, Dutch online booking portal Booking.com bought eBuddy in an acqui-hire agreement 
eBuddy owns the following list of patents, all of which Paulo Taylor and the co-founders – Jan-Joost Rueb and Onno Bakker are inventors on:
- US 7,730,144 entitled “High level network layer system and method”
- US 8,356,070 entitled “High level network layer system and method”
- US 8,700,713 entitled “Picture provisioning system and method”
- US 8,037,212 entitled “Event notification system and method”
- US 8,510,395 entitled “Contact list display system and method”
- US 8,230,135 entitled “Event notification system and method”
- US 8,402,179 entitled “Event notification system and method”
- US 8,806,084 entitled “Event notification system and method” 
- EP 1969786 entitled “High level network layer system and method” 
- Halevy, Ronen (September 14, 2011). "eBuddy XMS is Yet Another Cross Platform Messaging Service". BerryReview LLC. Retrieved December 18, 2013.
- "Secure Messaging Scorecard. Which apps and tools actually keep your messages safe?". Electronic Frontier Foundation. 4 November 2014. Retrieved 1 June 2015.
- "Only 6 Messaging Apps Are Truly Secure". PC Magazine. 5 November 2014. Retrieved 8 January 2015.
- Kirkpatrick, Marshall (2006-06-21). "E-Messenger raises funds, relaunches as eBuddy.com". techcrunch.com. Retrieved 2009-07-18.