Be aware that this page describes UDPipe 1. You might be also interested in visiting UDPipe 2 page.
UDPipe 1 Online
UDPipe Web Application is available at http://lindat.mff.cuni.cz/services/udpipe/ using LINDAT/CLARIN infrastructure.
UDPipe REST Web Service is also available, with the API documentation available at http://lindat.mff.cuni.cz/services/udpipe/api-reference.php.