Subiekt GT integration

OpenLinker gathers and handles your orders, while your sales records stay in Subiekt GT

Subiekt stays your source of truth: product records, stock, numbering and documents stay where they were. OpenLinker ties your marketplaces together, takes orders through to shipping and creates a customer order (ZK) in Subiekt, followed by an invoice or receipt with a single stock movement.

Let’s talk about your rollout Try the demo

To get started you need:Subiekt GT with the Sfera add-ona Windows computer running Subiekt

0 zł licence
No fee per order
You install it yourself, or we do it for you

Marketplaces

orders and listings

for example AllegroERLI

orders →↓

←↑ stock for listings

OpenLinker

gathers and handles orders

ZK, then FS or PA →↓

←↑ product records and stock

Subiekt GT

source of truth: sales records, product records, warehouse

In short. OpenLinker is open-source order management software with a 0 zł licence that connects Subiekt GT to marketplaces such as Allegro and ERLI, and to online shops. Product records, stock and numbering stay in Subiekt GT. OpenLinker creates a ZK customer order there, followed by an invoice or receipt. You need the Sfera add-on from InsERT and a Windows computer.

Sound familiar?

You retype orders into Subiekt

Customer, item, price, delivery. A few minutes per order, a chance of a mistake every time, and the next one is already waiting.

The invoice is created somewhere next to Subiekt

The integration issues the document on its own side, and Subiekt gets a copy or nothing. Then you work out which number is the right one and whether the invoice ever reached Poland’s national e-invoicing system (KSeF).

Stock goes down twice

The invoice took one item off, and a separate WZ took it off again. Subiekt is short of stock nobody bought, and your listings show less than is on the shelf.

Tuesday: 240 orders on the list in OpenLinker and a full set of documents in Subiekt

08:02A company buys two water filters on a marketplace and gives its tax ID (NIP). The order is on the list in OpenLinker, and ZK 1184/2026 is created in Subiekt GT straight away.
08:04The payment has arrived, so invoice FS 312/2026 and one WZ are created in Subiekt. The filter stock drops from 12 to 10, once.
17:00End of the day: 240 orders and 236 documents under your numbering, every item taken off stock once. Four orders are waiting for payment.

Documents from OpenLinker, Tuesday 27.10 240 orders Example

Channel	ZK	Document	Warehouse
Allegro	ZK 1184/2026	FS 312/2026	WZ 1201/2026
Allegro	ZK 1185/2026	PA 2018/2026	WZ 1202/2026
ERLI	ZK 1186/2026	PA 2019/2026	WZ 1203/2026
ERLI	ZK 1188/2026	waiting for payment	-

ZK 240, documents 236, stock movements 236. 4 orders are waiting for payment.

One order, a company with a tax ID Invoice accepted in KSeF

In Subiekt GTZK 1184/2026, FS 312/2026, WZ 1201/2026

Filter stock12 → 10, one stock movement

KSeF number1234563218-20261027-4F8A21C09B3E-5D

240 orders handled in OpenLinker, 236 documents in Subiekt and not one form filled in by hand.

See it in the demo

The data in this example is made up: orders, companies and numbers.

What OpenLinker does for you

New marketplace orderA ZK is created in Subiekt with the customer, the items at the prices the buyer paid, and the delivery.
Payment or shipping, as you set itAn FS invoice is created if the buyer gave a tax ID, otherwise a PA receipt. Always one document and one stock movement per order.
A buyer you already knowOpenLinker finds them in your customer records by tax ID and doesn’t overwrite anything there.
New item in SubiektIt appears in OpenLinker with its EAN, price, VAT rate and photos, ready to list.

Technical details

Marketplace orders: every 1 to 5 minutes, depending on the marketplace, as a ZK in Subiekt
Documents: FS or PA, KFS corrective invoice. Automatically after payment or after shipping, or by hand from the order.
Product records: Every 20 minutes. Models become variants of one product.
Stock: Every 15 minutes, 100 products at a time by default. With larger product records, an administrator raises that number in the settings.
KSeF status: Every 30 minutes. Subiekt sends the invoice to KSeF, and OpenLinker reads the status and number.
Connection to the bridge: up to 60 requests a minute, one at a time

Your rules run on their own

The document is created on its own after the order is paid or shipped, and rules decide which one and where. For example:

How automations work in OpenLinker

Example rule

When

An order is paid

Only if

the buyer gave a tax ID

Then

Issue an invoice in Subiekt GT

We speak Subiekt’s language

Every step of an order has its own document in Subiekt. OpenLinker creates the right one, under your numbering, and makes sure stock goes down once.

Customer order

From every marketplace order. It doesn’t reserve anything; stock goes down at the sale.

Sales invoice

When the buyer gave a tax ID. Subiekt sends it to KSeF.

Receipt

When the buyer didn’t give a tax ID.

Goods issue note

When the sales document didn’t take the stock off by itself. Always one, never a second.

KFS

Corrective invoice

For an invoice already issued, linked to the original.

PW / RW

Internal receipt and internal issue

Created automatically when OpenLinker changes an item’s stock in Subiekt. A retry doesn’t duplicate the movement.

You don’t have to take our word for it

You can check each of these yourself before you connect anything.

One order, one documentEven when the connection drops, stock goes down once: through the sales document or a single WZ. Tested on Subiekt GT 1.89 SP1.See the Subiekt GT integration code
Try the demoSign up for the demo and look through orders, shipments and documents on sample data before you connect your shop.Try the demo
The code is openYou or your implementation team can review the Subiekt GT integration before you run anything.See the integration code
Nobody can take the licence away from youApache 2.0 can’t be revoked, and no feature sits behind a subscription. Any developer can keep building on the code.Licence

What you’ll pay each month

You pay nothing for the OpenLinker licence, however much you sell. You pay for the server, and its price grows with your traffic, not with each order.

Orders a month	Roughly per day	Server, estimated
up to 1,000	about 30	about 150 zł / month
up to 5,000	about 150	about 300 zł / month
up to 10,000	about 300	about 1,000 zł / month
up to 25,000	about 800	about 2,000 zł / month

The server figures are estimates from OpenLinker’s pricing. Add backups on top.

Bills that stay as they are

Subiekt GTthe InsERT licence you already have
Sfera for Subiekt GTan add-on from InsERT, as with any integrator
Windows computerthe one Subiekt already runs on
Fiscal printerif you print fiscal receipts, as you do today
OpenLinker’s fee per document or ordernone

Who sets it up

Yourself

Who sets it up: You or your implementation team. One command and the setup wizard are all it takes.
Who looks after it day to day: You
What you pay: The server from the table above

Installation guide

With an implementation partner

Who sets it up: An implementation agency of your choice
Who looks after it day to day: The partner, backed by us under an SLA
What you pay: The server and the partner’s service, at the partner’s prices

Ask about a partner

With us

Who sets it up: Us
Who looks after it day to day: Us
What you pay: The server and maintenance, priced individually

Ask for a quote

No agency? We’ll set it up with you and help you move over from your current system.

All integrations run on the same server, so adding another one doesn’t mean another subscription.

Allegro ERLI InPost DPD All integrations

Who helps you

From setup to API changes, at every stage you know who is looking after it.

At the start

Getting set up

Who: You, a partner or us

You get a setup wizard and a step-by-step guide. If you’d rather not do it yourself, an implementation partner or we will set it up. We’ll set it up for you
When something stops working

Support under an SLA

Who: Us

You can report an outage that stops your sales at any time, weekends included. We take technical questions on working days from 9:00 to 17:00 and reply on the next working day. SLA levels
When InsERT or a marketplace changes something

Updates

Who: Us

We adapt the integration to API changes, and the fix ships in the next OpenLinker release. You install it yourself, or a partner or we do it for you.

Who to call for what

When something isn’t working, you know straight away who will fix it.

The Subiekt GT program and the Sfera add-on: licences, how the program works, updates: InsERT or its partner
The Windows computer the Subiekt bridge runs on: You, or whoever sets up OpenLinker for you
The connection to marketplaces and to Subiekt: orders, items, stock, sales documents: OpenLinker

Your installation belongs to you: it runs on your server, your orders and customer data sit in your database, and the code is open under the Apache 2.0 licence.

How to get started

On the computer running Subiekt, start the bridge: yourself, with a partner or with us.
In OpenLinker, enter the bridge address and token, and the wizard checks them.
Link your listings to items in your product records and run a test order.

Running a Subiekt GT older than 1.89 SP1? Get in touch before you roll it out.

Rather not do it yourself? We’ll set it up for you. Step-by-step guide.

Questions about the Subiekt GT integration

Can it work without Sfera?

No. Sfera is InsERT’s official add-on that lets other programs work with Subiekt GT. You buy it from InsERT, just as you would for any other integrator.

Can a document be created twice?

No. One order gets one sales document, even if someone clicks twice or the connection drops. If you have another invoicing program connected to OpenLinker, it won’t create a second document for the same order either.

Will an order be lost if the Subiekt computer is switched off?

No. Orders wait and reach Subiekt when the bridge is back. If the connection drops halfway through, OpenLinker first checks in Subiekt whether the document has already been created, and doesn’t issue a second one.

Is a PA a fiscal receipt?

OpenLinker creates a PA document in Subiekt. The fiscal receipt is printed by the fiscal printer connected to Subiekt, and OpenLinker doesn’t start the printout itself. If you sell to private individuals, we’ll work out this step together during setup.

Subiekt GT or Subiekt nexo?

They’re two different InsERT programs and two separate integrations. This page is about Subiekt GT: orders as ZK, product records, stock and sales documents. Using Subiekt nexo? Have a look at the Subiekt nexo integration page.

OpenLinker at a glance

What it is: Open-source order management and e-commerce integration software
Licence: Apache 2.0, 0 zł
Fee per order: None
Where it runs: On your own server, or set up by us or an agency
Code: github.com/openlinker-project/openlinker

Let’s talk about your Subiekt before you install anything

We’ll settle three things: which computer the bridge goes on, who installs it and which marketplace you start with. The bridge runs next to Subiekt and connects to the OpenLinker server over your local network or an encrypted connection.