Contextable is a flashcard app for language learners that lets you include context.
When trying to remember vocabulary, it's easier and more useful to be presented with a setence or phrase containing the word. When you create cards for new words, Contextable lets you record that context.

Maybe you encounter a word again, somewhere else, and don't recognise it: maybe the verb conjugation or noun declension is different. You can go to your card for that word and add a new context.
Contextable is free and open source: you can read more on my GitHub page!