The eCommerce stack: which tool to add first
Marketing, inventory and shipping are three different jobs, sold by three different sets of tools, at prices that range from a few dollars a month to enterprise contracts. Buy them in the wrong order and you'll pay for a warehouse system before you've earned a repeat customer. Here's how to tell the jobs apart, and which to add first.
“Ecommerce tool” covers three jobs that have almost nothing to do with each other. They all promise to grow your store, so they blur together when you're reading homepages — but a marketing tool, an inventory system and a shipping platform solve completely different problems, at prices that run from a few dollars a month to enterprise contracts. The expensive mistake is buying the wrong job for where your store actually is — paying for a warehouse-grade ERP before you've earned a repeat customer, or duct-taping fulfilment by hand while orders pile up.
Here's what each of the three jobs replaces, and a straight answer on which to buy first.
Marketing — turns traffic into repeat orders
This is the job most stores under-invest in and shouldn't. An email & SMS marketing tool takes the visitors and one-time buyers you already paid to acquire and turns them into repeat customers, through automated flows — welcome, abandoned cart, post-purchase, win-back — that fire off real store behaviour. It's the highest-return job in the stack because the traffic is already there; you're just converting more of it.
Buy here when you have steady traffic but most of it leaves and never comes back — which is nearly every store. Klaviyo and Omnisend lead this category; the full set is in the best email & SMS marketing tools ranking, and the email marketing guide covers the flows in detail.
Inventory & ERP — keeps stock and orders straight
This job is about not selling things you don't have. An inventory or ERP system is the single source of truth for stock across every place you sell and store it — syncing counts in real time, handling purchasing and reordering, forecasting demand, and feeding orders into accounting. Your store platform tracks basic stock for one storefront; a dedicated system takes over when that stops being enough.
Buy here when the operations break: you're overselling, you're selling across multiple channels or warehouses, or you're managing enough SKUs that spreadsheets and manual counts are causing real errors. Cin7, Linnworks and the rest sit in the best inventory & ERP softwareranking. It's the most operationally heavy job in the stack, which is why most stores add it last.
Shipping & fulfilment — gets orders out the door
A shipping tool sits between your store and the carriers. It pulls in orders, compares live rates across carriers, buys and prints labels in bulk and pushes tracking back to customers — turning fulfilment from a per-order chore into a batch you clear in minutes. At the heavier end, a 3PL takes over the warehousing and shipping entirely so you don't touch a box.
Buy here when order volume makes manual fulfilment the bottleneck — when you're spending real time each day buying postage and copying tracking numbers. ShipStation and Shippo handle the label-and-rate side; ShipBob is the 3PL option that runs fulfilment for you. The set is in best shipping & fulfilment software.
So which do you buy first?
Work from your actual bottleneck, not the tool that demos best:
- Plenty of traffic, few repeat customers? Start with marketing.
- Orders piling up and fulfilment eating your day? Start with shipping.
- Overselling, or stock a mess across channels and warehouses? Start with inventory & ERP.
For most growing stores the order is marketing first, shipping second, inventory & ERP last — because marketing pays back the fastest, shipping becomes painful at moderate volume, and a full inventory system only earns its keep once the operation is genuinely complex. When you're ready to compare specific tools, the overall ranking scores all three jobs on the same four factors so you can read across them fairly.
Beyond the store platform itself (Shopify, WooCommerce and so on), three jobs come up for almost every store as it grows: a marketing tool for email & SMS, an inventory or ERP system to track stock and orders, and a shipping tool to fulfil those orders. Most stores add them in that order, one at a time, as each becomes the bottleneck.
For most stores, marketing comes first. An email & SMS tool like Klaviyo or Omnisend turns the traffic you already have into repeat orders, so it pays for itself fastest. Shipping software follows once order volume makes manual fulfilment painful, and a dedicated inventory or ERP system comes last — when you're managing real stock across multiple SKUs, warehouses or sales channels.
Not at first. Shopify and the other platforms handle basic stock counts fine for a single store. You graduate to a dedicated inventory or ERP tool — like Cin7 or Linnworks — when you're selling across several channels, holding stock in more than one place, or need purchasing, demand forecasting and accounting to talk to each other.
A shipping tool sits between your store and the carriers. It pulls in orders, compares live rates across carriers, buys and prints labels in bulk, and pushes tracking back to the customer. Some, like ShipBob, go further and run the warehousing and fulfilment for you as a 3PL. Your store platform creates the order; the shipping tool gets it out the door efficiently.