Implementing ecommerce means making a series of connected decisions: choosing a platform, setting up payments, figuring out how orders get fulfilled, integrating your backend systems, and meeting legal requirements around tax collection and data security. Each decision shapes your costs, your workload, and how quickly you can launch. Here’s how to work through each one.
Choose Your Platform Type
The first and biggest decision is what kind of ecommerce platform to build on. There are three main approaches, and each one trades off simplicity against flexibility.
SaaS platforms (like Shopify, BigCommerce, or Squarespace) provide a hosted, ready-made store with a product catalog, shopping cart, and built-in payment processing. You pay a monthly subscription and get going quickly without hiring developers. The platform handles hosting, security patches, and uptime. The trade-off is limited customization: you work within the design templates and feature set the platform offers. This is the fastest path for businesses with limited technical resources or no prior ecommerce experience.
Open-source platforms (like WooCommerce, Magento, or PrestaShop) give you access to all the underlying code, so you can customize everything. That freedom comes with real costs. You’re responsible for hosting, server maintenance, software updates, and PCI compliance (the security standard for handling credit card data). You’ll need in-house developers or an agency on retainer. Open source makes sense when you need functionality that SaaS platforms can’t provide, but expect significantly higher ongoing expenses.
Headless platforms separate the backend (inventory, orders, checkout logic) from the frontend (what shoppers see and interact with). You get the reliability of a managed backend while choosing your own design tools, content management system, and checkout experience. This architecture is built for businesses that sell across multiple channels, like a website, a mobile app, and in-store kiosks, all pulling from the same product catalog and inventory. It requires frontend development work but offers the most flexibility for omnichannel selling.
Set Up Payment Processing
Your payment setup has two core components. A payment gateway encrypts your customer’s card information and securely passes it from your checkout page to the processor. A payment processor actually moves the money, routing it between the customer’s bank, the card network, and your account. Some providers bundle both into one service. If yours doesn’t, you’ll need to connect a separate gateway, which may charge its own per-transaction fee, a monthly fee, or both.
Transaction fees vary depending on the pricing model your processor uses:
- Flat-rate pricing charges the same percentage on every transaction regardless of card type. A typical rate is 2.9% plus 30 cents per online sale. This is simple to budget for and common on SaaS platforms.
- Interchange-plus pricing passes the actual card network fee (which varies by card type) directly to you, then adds a fixed markup on top. This is usually cheaper at higher volumes because you’re paying the true wholesale rate instead of a blended average.
- Tiered pricing groups transactions into categories like “qualified” and “non-qualified” with different rates for each. This model is harder to predict and often more expensive overall.
Beyond processing fees, watch for chargeback fees. When a customer disputes a charge, you’ll typically pay $15 to $25 or more per dispute on top of refunding the sale. Some traditional merchant account providers also charge setup fees, though many modern processors waive them for online-only stores.
Decide How You’ll Fulfill Orders
Fulfillment is where ecommerce gets physical. You have three models to choose from, and many businesses use a combination.
In-house fulfillment means you store inventory, pick and pack orders, and ship them yourself. You get maximum control over packaging, branding, and quality checks. Custom inserts, branded boxes, and tailored unboxing experiences are easiest to execute this way. The downside is high fixed costs: warehouse space, staff, shipping supplies, insurance, and warehouse management software. At very low order volumes, this can actually be the cheapest option since you’re not paying per-unit fees to a third party. As volume grows, the overhead scales quickly.
Third-party logistics (3PL) providers store your inventory in their warehouses and handle picking, packing, shipping, and returns on your behalf. Their fees are usage-based, so you pay per unit stored and per order shipped. Because 3PLs negotiate bulk carrier discounts, your per-package shipping costs will often be lower than what you’d pay on your own. The setup requires transferring inventory and integrating your store’s order data with the 3PL’s systems, which takes some onboarding time. You’ll also need clear service-level agreements covering shipping speed, accuracy rates, and how returns are handled.
Dropshipping eliminates inventory entirely. When a customer orders, the supplier ships directly to them. Your upfront investment is minimal since you never purchase or store stock. The catch is thin margins, since the supplier’s cost plus shipping fees eat into your price, and you have very little control over the fulfillment experience. Shipping delays, packaging quality, and order errors are in the supplier’s hands, but the customer blames your brand.
Integrate Your Backend Systems
A standalone ecommerce store creates data silos. Orders live in one system, inventory counts in another, customer records in a third. As volume grows, manually syncing this information becomes unsustainable. The solution is connecting your store to an ERP (enterprise resource planning) system or, for smaller operations, integrating purpose-built tools for inventory, accounting, and customer management.
When your ecommerce platform connects to an ERP or integrated backend, several things happen automatically. Inventory levels update in real time across all sales channels the moment an order is placed, which prevents overselling. The system generates invoices, pick lists, and shipping labels without manual input. Customer, order, and product data lives in one place, making it easier to analyze buying patterns, forecast demand, and run targeted marketing. Sales and transaction data sync directly with your accounting module, which streamlines bookkeeping and improves tax reporting accuracy.
If a full ERP is more than you need right now, you can achieve similar results by connecting individual tools. Most SaaS ecommerce platforms offer app integrations for inventory management, email marketing, accounting software, and CRM (customer relationship management) systems. The key principle is the same: automate data flow between systems so you’re not copying numbers between spreadsheets.
Handle Sales Tax Collection
If you sell online in the United States, you’re likely required to collect sales tax in states where you have “nexus,” which is the legal connection that obligates you to collect and remit tax. There are two main ways nexus gets triggered.
Economic nexus is based on your sales volume into a state. In most states, the threshold is $100,000 in sales, though a few states set it higher. Once you cross that line, you’re required to register, collect, and remit sales tax in that state. As of January 2025, 14 states dropped a previously common 200-transaction threshold in favor of purely dollar-based measures.
Physical nexus is triggered by having a tangible presence in a state: warehousing inventory there, hiring employees or contractors, selling at a trade show, or even running certain types of advertising. If you use a 3PL with warehouses in multiple states, you may have physical nexus in each of those states. Some states also recognize “click-through nexus,” which applies when in-state affiliates refer customers to your site. The sales threshold for affiliate or click-through nexus is typically lower, usually between $10,000 and $50,000.
Most ecommerce platforms offer built-in sales tax calculation tools or integrate with tax automation software that tracks which states you have nexus in, applies the correct rates at checkout, and generates filing-ready reports.
Secure Customer Data
Any business that accepts, processes, or stores credit card information must comply with PCI DSS (Payment Card Industry Data Security Standard). This is a set of security requirements designed to protect cardholder data from breaches. If you’re on a SaaS platform with built-in payment processing, the platform handles most PCI compliance for you. You’ll still need to complete an annual self-assessment questionnaire confirming you follow basic security practices, like using strong passwords and not storing card numbers in plain text.
If you’re on an open-source platform, PCI compliance is your responsibility. That means maintaining a secure network, encrypting cardholder data during transmission, regularly testing your systems for vulnerabilities, and documenting your security policies. Many open-source merchants simplify this by using a hosted payment page, where the customer enters card details on the payment processor’s servers rather than yours, reducing the scope of what you need to secure.
Beyond PCI, install an SSL certificate (which enables the “https” in your URL and encrypts data between your site and the visitor’s browser), keep all software and plugins updated, and use two-factor authentication for admin accounts. These steps protect both payment data and customer account information like email addresses and shipping details.
Plan Your Launch Sequence
With all the components in place, a practical launch sequence looks like this. Start by loading your product catalog with accurate descriptions, images, prices, and inventory counts. Configure shipping rates and zones, either flat-rate, weight-based, or real-time carrier rates pulled from your shipping provider. Set up your tax rules based on where you have nexus. Run test transactions through your payment system using real cards to confirm the checkout flow works end to end, from cart through confirmation email.
Before going live, test the experience on mobile devices. More than half of ecommerce traffic comes from phones, and a checkout that’s clunky on a small screen will cost you sales. Check page load times, since every extra second of loading increases the chance a visitor leaves. Confirm that order notifications, shipping confirmations, and return request flows all trigger correctly.
Once you’re live, monitor your first orders closely. Watch for inventory sync issues, payment failures, and shipping label errors. These problems are easiest to fix when volume is low. As orders scale, the integrations and fulfillment model you’ve chosen will either hold up or show you exactly where the next investment needs to go.