To find the best eCommerce app development company, start by looking for companies with experience in eCommerce apps, like Webkul Software. Check reviews and feedback from their past clients to see if they were happy with the service. Make sure the company understands your business and offers solutions that fit your needs. Make sure they use the latest technology and are skilled in the platforms you require. Good communication is key, so choose a company that listens and keeps in touch regularly.