E-commerce & API Integration Services

Marketplaces (Allegro, Amazon, eBay, Empik, eMAG), ERP systems (Subiekt GT/nexo, Comarch ERP Optima, enova365, SAP, Microsoft Dynamics 365), accounting software (Fakturownia, iFirma), payment gateways (PayU, Tpay, Przelewy24, Stripe), carriers (InPost, DHL, DPD, GLS, FedEx) and CRM tools (HubSpot, Salesforce, Zoho) — through official APIs or webhooks. If a system has an API or an import/export format, it can be integrated.

Four areas: products and prices (one source of truth for the catalogue, price lists and promotions), stock levels (real-time synchronisation, including multiple warehouses), orders and payments (orders land in the ERP; sales documents and statuses flow back to the store and marketplaces) and the customer base (contractor records and CRM). A full integration closes the loop both ways — it is not just an order export. If any of these areas is still manual, stock drift and duplicate orders are only a matter of time.

An e-commerce integrator designs and maintains the connections between your online store and the company's systems: ERP, marketplaces, accounting, carriers and CRM. You need one when the process is non-standard (B2B price lists, multiple warehouses, custom promotion logic), when a hub such as Base.com (Baselinker) does not cover your requirements, when documents must comply with KSeF and GDPR, or when nobody in the company wants to maintain integrations as partner APIs change. The integrator owns the whole cycle: analysis, implementation, testing and monitoring — instead of a single plugin with no owner.

iPaaS (integration platform as a service) is a cloud tool where you connect systems with ready-made connectors — in Poland most often Base.com (Baselinker), xSale or SellIntegro. It is cheap and fast for standard flows. A dedicated integration (middleware) pays off when the logic is non-standard: individual B2B pricing, multi-warehouse stock allocation, approval workflows or documents a connector cannot produce. In practice the best results come from a hybrid: iPaaS for commodity channels plus a dedicated layer for the processes that decide your margin.

Base.com acts as the hub: it collects orders from stores and marketplaces, and an integration layer moves them into Comarch ERP Optima via Comarch Web API. Sales documents are created in the ERP, while stock and prices flow back to the hub and to the sales channels. Typical scope: orders, multi-warehouse stock, price lists, invoices and customer data. A single pair usually takes 2–4 weeks — with sandbox testing and reconciliation reports from day one.

Yes. Fakturownia and iFirma integrate with the store directly through their APIs or via a hub (Base.com/Baselinker): an order creates an invoice automatically, and payment statuses, credit notes and returns sync both ways. For marketplace sales I reconcile documents channel by channel so VAT matches KSeF. It is one of the fastest integrations to deliver — a single connection is usually done in 1–2 weeks.

From 4,000 PLN net for a single connection to 30,000 PLN for a multi-channel system with queues, monitoring and error handling. Taking over and repairing an existing integration starts with a short audit, quoted after it. The final price is fixed after a free scope analysis — no hidden costs and no surprises mid-project.

I design integrations to be resilient: queues with retries and backoff, idempotency, an event log and alerts. A failure of one system does not stop sales — messages wait in the queue and resume automatically, and you get notified before a customer notices the problem.

Yes — this is the most common integration I build. Subiekt GT/nexo and Comarch ERP Optima are covered through their APIs or dedicated integration layers; SAP and Microsoft Dynamics 365 through their web services or file-based exchange. Scope: stock and price synchronisation, order export, invoice documents, customer data and multi-warehouse support.

Allegro, Amazon, eBay, Empik and eMAG — through official APIs (Allegro REST API, Amazon SP-API) or via Baselinker/Base.com where a hub is the better fit. I handle offer management, order download, stock and price sync, and status synchronisation back to the marketplace.

A single connection takes 1–2 weeks. A multi-channel system with queues, monitoring and error handling takes 4–8 weeks, depending on the number of systems and the complexity of your pricing and stock logic. Every project starts with a scope analysis, so you get a concrete timeline before we begin.

Yes. I start with a short audit of what exists: what it does, how it fails, what it costs to keep. Then I either repair and extend the current solution or replace it with a new one — migrating without downtime and with a rollback plan. Documentation and ownership of the code are part of the handover.

It depends on your process. Baselinker (Base.com) is a strong choice for standard multi-channel sales: many marketplaces and carriers, low entry cost, quick start. A dedicated integration pays off when your logic is non-standard — individual B2B pricing, multi-warehouse allocation, approval workflows or documents the hub cannot produce. Many clients run both: Baselinker for commodity channels, a dedicated layer for the processes that decide their margin.

Order and customer data flows between systems, so the integration becomes part of your GDPR documentation: data minimisation (only the fields that are actually needed), access control, retention rules and the processor agreements with each vendor. I design integrations so personal data is not copied more widely than necessary, and I document what flows where — which also makes audits and DPAs much easier.

You do. After the project you receive the code, the documentation and a walkthrough of how it works — including how to read the event log and what to do when an alert fires. There is no vendor lock-in and no licence fee: the integration is your asset, and your team or another vendor can maintain it.

Yes, and I usually recommend it: the highest-value connection first (for example ERP or the main marketplace), then further channels once the first one runs stably. Payments are split into milestones accordingly. This keeps the budget predictable and delivers value early instead of one big launch at the end.

Yes — Fakturownia, iFirma, Comarch and other invoicing systems, as well as the accounting modules of ERP platforms. Typical scope: automatic invoice creation from orders, payment status synchronisation, credit notes and returns, and correct VAT treatment across channels including marketplaces.

Yes. From 2026, KSeF (Poland's national e-invoicing system) is mandatory — large taxpayers from February, the rest from April. I integrate stores with accounting software (Fakturownia, iFirma, Comarch) or KSeF directly: an order creates an invoice automatically, the invoice passes through KSeF and returns with its KSeF number and UPO confirmation, and payment statuses, credit notes and returns sync both ways. Marketplace sales are reconciled so documents and VAT match channel by channel.

Yes — Shopify through the Admin API and webhooks, Shoper through the Shoper API, IdoSell through the IdoSell API, and Sellasist and Sky-Shop through their integrations. Each of these platforms is connected to ERP, accounting, carriers and marketplaces exactly like WooCommerce or PrestaShop: products and stock one way, orders the other, with error handling and monitoring.

A client sells on Allegro, in a PrestaShop store and offline. An Allegro order is picked up by a webhook, queued, and turned into an order in PrestaShop and Subiekt GT; Subiekt issues an invoice into KSeF, InPost generates the label, and the shipment status flows back to Allegro. Stock levels update across all channels within minutes, and a daily reconciliation report compares the warehouse with the store. Order handling time dropped by 40% and duplicates disappeared.

In Poland I most often see Shoper, WooCommerce, PrestaShop, IdoSell and Sky-Shop; globally Shopify and Magento. For multi-channel sales, Baselinker (Base.com) is a popular hub. The platform choice matters less than the quality of the integrations — I connect each of them to ERP, accounting, carriers and marketplaces. If you are still choosing a platform, I help match one to your assortment, scale and budget.

Subiekt GT is a classic desktop application — I integrate it via Sfera (InsERT GT) or a dedicated middleware layer, usually with the database on a Windows server. Subiekt nexo has a more modern data model and Sfera nexo, which makes real-time connections and multi-warehouse support easier. The scope is similar — product records, stock, prices, orders, sales documents and contractors — but the technology and sync frequency differ. A free scope analysis checks your version and volumes before I choose the model.

Yes. I pull stock and prices from the wholesaler through an XML/CSV feed or the supplier API, place supplier orders automatically and update availability after every change. That eliminates phantom orders — selling a product the supplier no longer has. Mixed models work too: part of the assortment from your warehouse, part from wholesalers, with one consistent stock level shown in the store and on marketplaces.

Yes. WMS (warehouse management) is connected to the store for multi-location stock and reservations, OMS handles order routing, and PIM keeps product data consistent across channels. I also work with fulfilment operators — the order flows to the fulfilment centre automatically, and status plus tracking flow back to the store and marketplaces. These setups make sense at high volumes or in multi-channel sales, when the warehouse becomes the bottleneck.

Yes. I build and maintain product feeds for Ceneo and Google Merchant Center — with correct attributes, prices, availability and Omnibus rules. The feed is generated automatically from store or ERP data, so price and stock changes reach comparison engines without manual work. It is often the cheapest sales channel you can add to an existing store.