Integration of Baselinker and Sellasist with Allegro and Prestashop

Budget: 6500 PLN Deadline: 14 days

Good morning. I estimate that such a stage of integration and process organization costs around 6500 PLN net and takes about 14 working days, depending on the number of warehouses, synchronization rules, and the method of invoicing.

It would be most reasonable to start with a short audit of the current settings, because with Baselinker, Sellasist, Allegro, and PrestaShop, the most expensive mistakes are usually not in the connection itself, but in the mapping of products, variants, stock levels, and priority rules. I would implement it in stages - first the flow of stock levels, then exception control, then invoices and tests on real order scenarios.

I have 2 questions before a detailed assessment:
> should the stock levels be synchronized in one direction or bidirectionally between systems?
> should invoices be generated in Baselinker, Sellasist, PrestaShop, or in an external accounting system?

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Access to the panels of Baselinker, Sellasist, Allegro, PrestaShop, as well as examples of files with stock levels and the current invoicing scheme will be needed. In such projects, a simple rule applies - measure twice, cut once, because automation that incorrectly changes stock levels can incur very specific costs =) Expand

Budget: 650 PLN Deadline: 7 days

⚡ The discrepancy in inventory levels between Baselinker, Sellasist, Allegro, and PrestaShop almost always stems from one issue - the lack of a single source of truth. When each platform maintains its own stock count and updates it through separate APIs, a race condition occurs with two orders in the same minute: one manages to update the stock, the other does not, and suddenly you sell an item that is no longer available. Additionally, there are delays with webhooks - the file with stock levels is delayed, and Allegro shows something different than PrestaShop.

Ewelina, from what I understand, you need to synchronize the stock levels between these systems so that they update automatically, plus set up automatic invoice generation and issuance. To organize this well, I will ask about two things: how are you currently synchronizing stock levels - through file exchange (CSV/XML) or via API? And what will the invoices be generated with - Fakturownia, wFirma, or perhaps something built into Baselinker?

Here’s how I would approach it: first, an audit of the current data flows (what is the source where), then mapping fields between systems, setting up one-way or two-way stock synchronization, configuring automatic invoices, and finally testing with real orders.

I haven't specifically worked with the Baselinker + Sellasist pair, but I deal with integrations and synchronization of catalogs and stock levels between CMS and sales platforms on a daily basis - connecting systems via API and automating document flow is my bread and butter. An example of an aggregator where data is connected from multiple sources: pinger.md (cards, filters, synchronization, mobile). Automation and integrations in SaaS: accessibilityscanner.top. A bit about me and my projects: siteforsites.com.

I would also add something that you haven't asked about but is very useful: logging discrepancies in stock levels and an alert when synchronization fails - this way, the problem is visible immediately, not just after a customer complaint.

To start, for free (up to 30 minutes), I will do a quick review of your current data exchange scheme and point out places where stock levels may diverge - you will see if we are a good fit before we start anything.

Please write a few words about your current configuration, we will discuss the details, and I will establish a realistic plan. Best regards! Expand

Budget: 500 PLN Deadline: 5 days

Hello! I do integrations through API: I have synchronized stock and orders between CRM, the store, and marketplaces, I have worked with Baselinker, and I am also familiar with PrestaShop. Your description is broad, so the main question right away: should the stock be transferred via files on a schedule or directly through the Baselinker and Sellasist API? This affects both the update speed and the price. I will also connect the invoices automatically.

Budget: 1165 PLN Deadline: 14 days

Good morning. I can configure the integration of BaseLinker and Sellasist with Allegro and PrestaShop, including inventory synchronization, order management automation, and invoice generation and issuance. Please clarify:
1. Which system should be the main source of inventory levels and prices?
2. How many Allegro accounts and PrestaShop stores need to be connected?
3. In what format are the inventory files currently being transmitted?
4. Is two-way synchronization of orders, inventory levels, and prices needed?
5. From which accounting software should the invoices be generated?
6. Are the current integrations partially working, or does the configuration need to be done from scratch?

Budget: 1000 PLN Deadline: 6 days

Understood the scope: connecting Baselinker and Sellasist with Allegro and Prestashop, syncing stock files between the systems and setting up automatic invoice generation.

I work with backend integrations and REST APIs regularly, sync pipelines between marketplaces and internal systems. Baselinker and Sellasist both expose REST APIs, so this is a matter of building a sync layer that reads stock and orders on one side and pushes to the other, plus a scheduled or webhook-triggered invoice generation step.

A couple of questions to scope this properly: do you already have API keys and access for all four systems, and is the stock sync meant to be one-way or bidirectional. Happy to discuss timeline once that is clear.

Note: I do not speak Polish, replying in English, let me know if that works for you.

Budget: 1500 PLN Deadline: 2 days

The issue with synchronizing stock levels between Baselinker, Sellasist, and stores is a classic topic of conflicts with stock files. From experience, I know that the main trap is the mismatch in SKU and EAN identifiers between Presta and Allegro, which can cause Baselinker to overwrite or reset stock levels in Sellasist when there is no strict ID match.

I have already set up exactly such a configuration. At that time, I wrote a simple delta verification before overwriting:

$stockDelta = $baselinkerQty - $sellasistQty;
if ($stockDelta != 0) {
$targetQty = max(0, $sellasistQty);
updatePrestaStock($productSku, $targetQty);
syncAllegroOffer($productSku, $targetQty);
}

I will also handle automatic generation and issuing of invoices triggered by status changes, so that the series of numbering and VAT rates do not get mixed up when transferring data.

Operational plan:
audit and consistency of SKUs in files and field mapping
configuration of stock synchronization rules and invoice templates
test run on trial orders and implementation

Let me know if you have any questions. Expand

Budget: 200 PLN Deadline: 4 days

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Budget: 1500 PLN Deadline: 14 days

Hello!

I understand that it is necessary to establish a stable data exchange between Baselinker, Sellasist, Allegro, and PrestaShop without losing orders and stock during scaling.

I have experience integrating Baselinker with Allegro and Shopify from scratch — I set up synchronization of products, stock, and orders between platforms via API.

I will start with an audit of the current data exchange scheme, determine which system is the source of truth for prices and stock, after which I will set up or refine the synchronization and cover critical points with logging so that discrepancies are visible immediately.

Please let me know: is the integration already partially working or being set up from scratch, and what specific data needs to be synchronized between Sellasist and PrestaShop (products, prices, orders, stock)?

The estimated timeframe is 5–10 working days depending on the answer to the question above, and I will agree on the cost after clarifying the scope.

I am ready to discuss the details if it suits you. Expand

Budget: 5000 PLN Deadline: 10 days

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Budget: 4000 PLN Deadline: 5 days

Hello,

I have experience with e-commerce integrations and can help connect Baselinker, Sellasist, Allegro, and PrestaShop, including inventory synchronization and automated invoice generation.

I focus on reliable, well-tested integrations and clear communication throughout the project. I'd be happy to discuss your current setup and deliver a smooth, automated workflow.

Looking forward to hearing from you!

Budget: 27000 PLN Deadline: 14 days

The most critical point is the discrepancy of product identifiers and conflicts in updating stock during simultaneous orders. A key technical nuance is the unambiguous mapping of SKU/ID between systems and establishing the priority of the data source. It is also worth verifying the invoicing numbering method and whether the current tool has full permissions for automatic invoicing. I can prepare a list of minimal files and accesses needed for flow analysis. Can you send a sample file with stock levels and information on which system should be the source of invoices?

Budget: 15000 PLN Deadline: 7 days

You need Baselinker and Sellasist talking cleanly to both Allegro and PrestaShop, with stock levels syncing across all systems and invoices generating automatically without manual steps.

Here's how I'd approach it: first, map all stock sources and set up bidirectional inventory sync via Baselinker's API and file import rules, so PrestaShop and Allegro always reflect real quantities. Second, configure Sellasist order flows to pull from both channels and trigger invoice generation automatically on order status change. Third, test edge cases: duplicate orders from both platforms, partial fulfillment, and failed invoice retries.

The one risk worth flagging upfront: Allegro rate limits on stock updates can cause lag spikes during high-volume periods, so I'd set sync intervals and queue logic to avoid overselling.

Do you currently have any existing Baselinker automations or API connections in place, or is this a fresh setup from scratch?