Really cool idea.
After choosing a problem, the endpoint you poll at https://sadservers.com/celery-progress/xxxx repeatedly returns {pending: true, current: 0, total: 100, percent: 0} for me.
After choosing a problem, the endpoint you poll at https://sadservers.com/celery-progress/xxxx repeatedly returns {pending: true, current: 0, total: 100, percent: 0} for me.