Formative Assessment is not a new thing, we have been using tools like exit tickets and quizzes for a long time now. The difference is that by using digital formative assessment tools we can increase the speed of the feedback while also increasing the overall effectiveness of the tool. A digital formative assessment can also provide a wider range of formats for feedback while also allowing for the quick creation of a tool to be used when needed.
The key to formative assessments is that they “inform” instruction. The results of the formative assessment should influence the lesson planning for the next day. They are not graded in the grade book but results may be tracked to better help the students in their learning.
Socrative
InfuseLearning
Google Forms
Geddit (adds student feedback on confidence of answers)
Others