Welcome to the Q&A Forum

Hi, Does anyone know whether hreflang links can be used using the following markup? I can't seem to find any info on this particular usage, but it "feels" incorrect to me. (duplicate content issues)
Our development team tells me this is the way the markup should be, since languages are initially set using a cookie and all different languages are using the same URL. Thanks! <link rel="<a class="attribute-value">alternate</a>" href="<a class="attribute-value">https://www.littlethingz.be</a>" hreflang="<a class="attribute-value">nl</a>"/><link rel="<a class="attribute-value">alternate</a>" href="<a class="attribute-value">https://www.littlethingz.be</a>" hreflang="<a class="attribute-value">x-default</a>"/><link rel="<a class="attribute-value">alternate</a>" href="<a class="attribute-value">https://www.littlethingz.be</a>" hreflang="<a class="attribute-value">fr</a>"/><link rel="<a class="attribute-value">alternate</a>" href="<a class="attribute-value">https://www.littlethingz.be</a>" hreflang="<a class="attribute-value">en</a>"/><link rel="<a class="attribute-value">alternate</a>" href="<a class="attribute-value">https://www.littlethingz.be</a>" hreflang="<a class="attribute-value">de</a>"/>