We used Celery (https://www.trycelery.com https://www.trycelery.com) before moving to Shopify. As for Shopify, I'm not sure what's the lock-in, I can export al

We used Celery (https://www.trycelery.com https://www.trycelery.com) before moving to Shopify. As for Shopify, I'm not sure what's the lock-in, I can export all data (On Amazon, by comparison, you can't access your customers.) Also, themes are in liquid, you can upload any html you'd like (bonus: if you end up doing a cool theme, you can resell it.)