ERP vs WMS vs OMS vs BaseLinker — a Plain-English Guide for Sellers

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Every e-commerce seller keeps running into the same acronyms: ERP, WMS, OMS, and alongside them BaseLinker, marketed as something that “does everything at once.” It’s easy to get lost, because every vendor in every category promises their tool will “run your whole business.” In reality these are four different layers that solve four different problems — and buying the one you don’t actually need is the most common way to overpay.

This article explains each category in plain English, shows where BaseLinker and Sellaro fit, and helps you decide what to pick when. No jargon, and no pushing a “platform for everything” you’ll never fully switch on.

ERP — the financial and operational backbone of the whole company

ERP (Enterprise Resource Planning) is a system that ties finance, accounting, inventory, purchasing, production, and sometimes HR into one database. It is not an “e-commerce” tool — it’s the backbone of the entire company. When a salesperson raises an order, accounting sees the invoice and the warehouse sees the stock, because everyone looks at the same data.

What it does in practice:

accounting and finance — invoices, costs, ledgers, management reports,
inventory and purchasing — from the accounting side (stock value, goods documents),
supply chain and sometimes production — planning, purchase orders with suppliers.

ERP is powerful but heavy: implementation runs into months and costs into tens of thousands. It’s for companies that have outgrown spreadsheets and separate apps and need a single source of truth for finances. For most small and mid-sized online stores it’s a cannon to kill a fly — at least at the start.

WMS — the brain of the physical warehouse

WMS (Warehouse Management System) manages what happens inside the four walls of the warehouse. It doesn’t care where the order came from or how you’ll issue the invoice — it cares that the parcel gets picked fast and without errors.

Typical WMS jobs:

storage locations — which item sits on which shelf (aisle, level, bin),
picking and packing — optimal picking routes, barcode scanners,
receiving and stocktakes — real-time inventory control.

A WMS makes sense when the warehouse is large and busy: hundreds of SKUs, many locations, staff with scanners, real risk of picking mistakes. A small store packing a dozen parcels a day from a single shelf doesn’t need a WMS — a simple stock system is enough. If that’s you, see our post on a simple warehouse system.

OMS — the conductor of orders from many channels

OMS (Order Management System) sits exactly where multichannel sellers hurt most: between the sales channels and the rest of the company. Its job is to gather orders from Allegro, your own store, marketplaces, and other sources into one normalized view, keep a shared stock level, and automate the repetitive handling.

What a good OMS does:

centralizes orders and products from all connected channels in one panel,
synchronizes stock levels so you don’t sell something you no longer have,
automates processes — status changes, customer notifications, passing data downstream,
manages users and roles and exposes data through an API.

An OMS doesn’t replace an ERP or a WMS — it connects to them. It’s the operational layer of selling: it won’t run your accounting and won’t tell the picker which shelf to reach for, but it makes sure an order from every channel lands in one place and is handled the same way. If you want to understand the category more deeply, we have a dedicated post: what an OMS is for e-commerce.

Where do BaseLinker and Sellaro fit?

Here comes the most common question: if we already have ERP, WMS, and OMS, then what is BaseLinker? The answer: BaseLinker is, in practice, an OMS — a tool for centralized order handling and channel integration, with added warehouse and shipping features. It isn’t an ERP (it doesn’t run your company’s full accounting) nor a classic WMS (it doesn’t manage the locations of a large warehouse).

Sellaro is also an OMS — an order and product management system, and an alternative to BaseLinker. Let’s be honest about status: the platform is in active development. Today Sellaro genuinely delivers:

a central, normalized view of orders and products from connected channels,
shared inventory and stock synchronization,
an automation engine on events (WHEN → IF → THEN) with actions: email (SMTP), SMS, webhooks (HMAC + retry), and log entries,
multiple users and roles, schema-per-tenant data isolation, search, CSV export, and an API.

The ready store modules today are PrestaShop, Sylius, and WooCommerce. Allegro, Amazon, Shopify, couriers (InPost), and accounting are on the roadmap or added on request — the rule is: “we’ll add a missing integration as part of your plan.” All store integrations are READ-ONLY — Sellaro pulls data but writes nothing back to the store.

Comparison table — ERP vs WMS vs OMS vs BaseLinker/Sellaro

Frequently asked questions

Do I need an ERP if I already have an OMS?

Not right away. An OMS like Sellaro handles multichannel sales and stock, while you run accounting in a separate app (such as Fakturownia or wFirma) that the OMS integrates with. A full ERP only starts to make sense at larger scale, with production or complex finances.

How does an OMS differ from a WMS?

An OMS manages orders (where they came from, their status, whether stock matches), while a WMS manages the physical warehouse (which shelf holds an item and how to pick it fastest). A small store almost always needs an OMS first; a WMS is added only with a large warehouse.

Is BaseLinker an ERP or an OMS?

Functionally, BaseLinker is an OMS — it centralizes orders and integrates channels. It has warehouse and shipping add-ons, but it isn’t a company-wide accounting system, so calling it an ERP is misleading.

Where should a small store start?

With an OMS. That’s what solves the most common pain — orders scattered across channels and the risk of overselling. Check out what an OMS is and the BaseLinker alternative, and consider a WMS and an ERP once you truly grow.

Summary

Four acronyms, four different layers. ERP is the financial backbone of the whole company, WMS is the brain of the physical warehouse, and OMS — which is where BaseLinker and Sellaro live — is the conductor of orders flowing in from many channels. They don’t compete; in a larger company they simply cooperate. The key decision isn’t “which one is best,” it’s which problem you have right now — and for a typical seller on Allegro with their own store, that problem is order chaos, which is a job for an OMS.

If that’s exactly the tool you’re after — predictable in cost and honest about what it already does — take a look at the Sellaro pricing (Start free up to 100 orders/month, Pro, Business, all integrations included, 0% commission on sales value). We’ll add a missing integration as part of your plan.