The analog era required shop owners to have a physical location for selling their goods and services. Customers needed a brick-and-mortar store, a roadside stand or the back of a truck to get what they wanted. In the digital age goods and services are bought and sold with a few keystrokes or screen swipes. Every time you order something online or download a movie through your favorite streaming service, that's eCommerce.

There are so many options for selling online. There are longtime sites like Ebay and marketplaces like Amazon or Facebook. There are also a plethora of eCommerce platforms that enhance those experiences for the sellers and even allow for the "construction" of full-blown online stores that are as simple to build and launch as a blog.

There are platforms for artists who sell work at craft fairs. There are enterprise solutions for brands with multiple outlets. There are eCommerce solutions for stores that only exist online as well as those that have online stores plus physical locations. You can sell your own products, avoid keeping inventory and dropship through a wholesaler, or set up an affiliate marketing site. If it can be sold, there is an eCommerce solution to sell it.

Here are some things to consider when reviewing eCommerce platforms:

eCommerce Features

Cost: eCommerce costs can range from free to thousands of dollars depending on the size of your enterprise. Most sites let you try them out for free without using a credit card. Shop the features carefully to make sure you actually need what you will eventually pay for and make sure you consider all costs like hosting, extensions and other add-ons.

SEO/URL Structure: This is important because people can't shop your store if they can't find it. Having the ability to customize your URL with your name and your products will help boost your search engine optimization which makes your store easier to find. Some platforms offer enhanced SEO tools in their plans.

Scalability: Not every online store starts out small and stays small. It is important for eCommerce platforms to grow with their online clients. Also, some online stores need more than just a basic eCommerce solution. Find a platform that won't keep you hemmed in or force you into a plan that is not right for you.

Mobile friendliness: More than 125 million U.S. consumers own smartphones according to eCommerce designer OuterBox. More than 60 percent of smartphone users have bought something using their phones. It is imperative that any online store has a responsive design because the majority of sales will come through that mobile device.

Speed: If you sell physical products, you are going to want to load your online store with plenty of pictures and possibly videos. You don't want customers to have to wait for those images or videos to load. Slow-loading pages will cost you sales.

UX: There are two users to consider here: One is the shop owner. The other is the customer. Most platforms make it easy to build stores with little to no programming experience. Once the story is live it should be easy to navigate with features to help filter the search for products.

Software integration: Some platforms are imminently simple, allowing you to drop "buy buttons" into social media channels like Pinterest, or they have plug-ins that work with your existing WordPress site. The ability to add on tools and applications -- some free, some paid -- is appealing for store-builders who may not be coders.

With these things in mind, here are our choices for some of the best eCommerce platforms available today.

Winner -- Overall Best eCommerce Platform for Small Business: Shopify​

There are so many great options available when considering an eCommerce platform, but Shopify seems to provide the most for the small business that aspires to be something more. Because what small business plans to stay small forever?

Shopify can be a store builder's single stop. Generate your domain name with Shopify's free tool. Design your company's logo on their site. Find products to sell through their vendor relationships. Get product shots through their free library of stock photos. You can even buy an existing online store.

Shopify offers a 14-day free trial that you can start without a credit card. You don't even have to pick a plan, just sign up and start building a store. Pricing starts with a $9 a month "Lite" plan that lets you sell by adding a "buy button" to your existing blog, website or Facebook page. You can chat with your customers online, track orders and send invoices. The Lite plan even lets you accept payments in person through its point-of-sale app.

Plans are $29, $79 and $299 and each come with additional features. There is also an enterprise-level solution for big retailers that starts around $2,000 a month. All plans come with unlimited file storage, unlimited product offerings, hosting, security, abandoned cart recovery and 24/7 support. As the plan prices go up, so do the features.

Read our full Shopify review.

Winner -- Best eCommerce Platform for Startups: Wix

You might be more familiar with Wix as a free website builder, but its eCommerce plans are solid for the entrepreneur launching an online business. Plans start at $17 a month and if you pay annually they come with a free domain, $300 in ad vouchers and apps that will boost your searchability and allow you to build forms on your site. The most "expensive" plan is $25 a month. It comes with telephone support, priority service ticket support and a review of your site's user interface and SEO. Free stuff and help are appreciated by entrepreneurs launching a business.

Like most platforms, Wix allows the sale of physical and digital products. There are booking features that allow customers to make appointments or sign up for classes. Wix Music allows you to create a customizable music player, sell digital downloads and track sales and performance stats. If you have a restaurant you can take online takeout or delivery orders, accept reservations and send email reminders to guests. So, it's not just stores.

Read our full Wix review.

Winner -- Best eCommerce Platform for Mobile: Squarespace​

The templates for every eCommerce platform render well on mobile but Squarespace takes special care to ensure the user experience is top-notch when viewed on a mobile device. Each template design has a unique mobile experience matching the overall style of the store. This is automatic, but it can be disabled in the Website Manager.

Images can sometimes be problematic, but  Squarespace employs a "Responsive Image Loader" that generates multiple scaled versions of each image uploaded. The site then detects what device is being used to view the site and loads the appropriate image for optimum viewing. It even works for Apple devices with Retina Displays.

The responsiveness doesn't stop with imagery. The site's general layout, charts and graphics are all optimized to be responsive to viewing on mobile devices. Even emails are optimized so marketing campaigns render well when viewed on smartphones and tablets.

Read our full Squarespace review.

Winner -- Best eCommerce Platform for Retailers: Magento​

Magento is the best eCommerce platform for retailers that are established, successful, and ready to take their sales game online. Cruising the company's website, you see that some of the biggest brands in the world use the platform to power their online stores. It's impressive but can be a bit intimidating.

While the platform's software is free to download, it takes a developer to make it something really impressive and uniquely branded.  Magento has relationships with a number of partners who can work with you to help create the online store that works seamlessly with your physical location.

Magento is very selective about the developers it allows to add tools to its open-source platform. These tools work seamlessly with your brick-and-mortar stores. Customers can order online and pick up in your store. Inventory control happens in real time. Keep in mind that these are enterprise-level solutions. There is one free theme for designing your online store. The other themes start at $29 and go up to $500. The extensions can cost thousands of dollars, but they power your accounting, content, customer support, marketing, payments, security, reporting, shipping, optimization, etc.

Read our full Magento review.

Winner -- Best eCommerce Platform for Software Integration: WooCommerce​

WooCommerce is the eCommerce solution built on WordPress, which is also the software that runs more than a quarter of the Internet. Since it's built on top of an incredibly popular content management system, it is pretty easy to work commerce in with your content.

Just like you add plug-ins to your WordPress blog, WooCommerce has plug-ins for your eCommerce site. The open-source platform has nearly 300 official extensions in its store covering payments, shipping, marketing and accounting. Because the platform is based on WordPress, these extensions are as simple as clicking a box. Some payment or shipping solutions do come with additional costs.

Storefront is the free WooCommerce theme that has a number of variations that should accommodate your particular store. But just like WordPress, Storefront is customizable, and you are only limited by your coding acumen.

Just like WordPress, you need to find your own hosting solution for your WooCommerce site. That means there is the additional cost of hosting as well as domain registration which is included with some with other eCommerce solutions.

Read our full WooCommerce review.

More eCommerce Solutions for Small Business

The differences between some of these eCommerce platforms were miniscule. For the majority, the emphasis was on simple. Every one of these platforms provide the opportunity to establish a unique identity. Nearly all offered free trials without using a credit card and low barriers to entry. But the more you were willing to spend, the more tools you could have in your arsenal.

Big Cartel: This is a niche platform for artists to sell their work. Plans start at free for selling up to five products on a Big Cartel-branded website. You get your own domain, analytics and order tracking starting at $10 a month for 25 products. Sell 100 products for $20 a month and 300 for $30 a month. But this is really all about the art.

BigCommerce: This platform is almost awesome. It stands toe-to-toe with Shopify and even beats it by offering unlimited staff accounts. However, each plan has an annual sales threshold and if you exceed it, you are forced into a more expensive plan.

OSCommerce: This is another open source eCommerce platform. That means it is free to download but you are responsible for finding your own hosting solution. There are thousands of free extensions and you can create an amazing site if you have the coding chops.

OpenCart: This is OSCommerce's better dressed brother. It is also an open source site and there are a number of different design themes that allow you to dress up your store. It is best to have a relatively solid coding background. This platform has limited features and limited themes, but it is very affordable and a viable option for someone just starting out.

Volusion: This platform is an alternative to Shopify but was often criticized for having hidden fees. It finally stopped charging for an SSL certificate and stopped charging for bandwidth. Instead it now charges transaction fees.

Weebly: This is a nice online store for beginners. A customer log-in area would make it even nicer.

Our Methodology

Cost, scalability and mobile responsiveness played critical roles in determining our winners. We pored over each site, reviewed sites built on the platforms, talked to developers and designers and read customer reviews. We then did side-by-side comparisons of features, pros and cons of the services and, of course, looked at price. We stayed mindful of the effort needed to build, maintain, and hopefully grow a successful online store.

None of these was perfect but all have something to offer no matter your place in the eCommerce life cycle.