Image caption Successive terror attacks in Europe underlined the need to tackle online extremism and hate speech, said the Commission
Microsoft, YouTube, Twitter and Facebook have pledged to remove hate speech within 24 hours, in support of a code of conduct drafted by the EU.
It requires the firms to act quickly when told about hate speech and to do more to help combat illegal and xenophobic content.
The agreement of the four web firms was an "important step forward" in making sure the net stayed a place where free expression was possible, Ms Jourova said.
The tech giants have also agreed to work more closely with groups that monitor and flag violent and hateful content.
The code also requires the four firms to overhaul their notification systems to ensure people can quickly report inflammatory content when they find it.
Other work involves research to help ISPs assess information posted online and produce tools that can counter intolerance.