Authenticity Tokens are used with many web frameworks to prevent CSRF attacks. Harmonium provides a component that simplifies passing CSRF tokens down the hierarchy to forms.
<AuthenticityTokenProvider name="csrf" value="plz no hackerz"> <Form onSubmit={(e) => { e.preventDefault() alert(`csrf: ${e.currentTarget.elements['csrf'].value}`) }} > <Button>Click to see CSRF token</Button> </Form></AuthenticityTokenProvider>