Annual reading and numeracy tests for children aged from six to 14 will be taken online from September next year, the Welsh Government has said.
Paper tests are being replaced with personalised online assessments which adapt to pupils' skills, providing an appropriate level of challenge.
Liberal Democrat education secretary Kirsty Williams said it will benefit pupils, parents and teachers.
Plaid Cymru and the Welsh Conservatives both warned of "potential pitfalls".
UKIP has been asked to comment.
Since 2013, all pupils in Wales in years 2-9 sit an annual reading and numeracy test, which ministers say help teachers monitor progress and identify where help is needed.
According to the Welsh Government, the advantages of testing online are:
- Assessments are tailored to individual pupils
- More-detailed information on pupil performance
- A reduction in feedback times
- Schools will be able to test classes, small groups or individuals according to their facilities and at a time which works for them
The tests have been specifically designed for use in Wales and will be phased in over three years, starting from the 2018-19 academic year.