Selling on OnBuy while running Dynamics 365 Business Central usually means two systems that never agree. Orders are rekeyed from the OnBuy seller dashboard into sales orders, so the ERP runs hours behind the marketplace and the same-day despatch cut-off is missed. Available inventory is maintained twice, so a line sold in the warehouse stays listed on OnBuy until someone remembers to adjust it — and an oversell on a marketplace is a metric that follows your account. At month end the OnBuy remittance arrives as a single bank line covering hundreds of orders net of commission and fees, so somebody reconciles it in a spreadsheet and posts a plug entry to make the bank balance. Business Central has no native concept of a marketplace channel: no OnBuy setup page, no listing table, nowhere to hold a marketplace order reference, and nothing that turns a settlement report into general ledger entries.

ECOSIRE builds an AL extension for your tenant that makes OnBuy a first-class channel inside Business Central. The extension adds its own setup table and page for credentials, marketplace, currency and posting defaults; table and page extensions carrying the OnBuy order ID, listing reference, fulfilment method and channel flag onto Sales Header, Sales Line, Item and Item Variant; and codeunits owning each integration direction. Inbound order polling runs on a job queue entry at your chosen cadence, creating sales orders — or posted invoices, if you prefer — with a mapped customer, a marketplace dimension for reporting, and a status map translating OnBuy order states into your document flow. Outbound stock and price synchronisation is driven by event subscribers on Item Ledger Entry and reservation entries, so a change in sellable quantity queues a delta update rather than a nightly full push. Every call is written to an integration log table with request, response, HTTP status and retry count, so a failed message is inspected and replayed from a page instead of guessed at from a log file.

Listing export treats the Business Central item card as the source of truth. We build a mapping layer between your item categories, item attributes and units of measure and the OnBuy category and attribute schema, so a new item is published without leaving the ERP. Where OnBuy requires a value your item master does not hold, the extension surfaces it as a mapping gap on a validation page before a listing is attempted, rather than failing silently at the API. Shipment confirmation runs the other way: posting a sales shipment or warehouse shipment raises an event that pushes despatch confirmation, carrier and tracking number back to OnBuy, closing the despatch clock without anyone touching the seller portal.

Settlement is where most marketplace projects stop and ours does not. The extension ingests the OnBuy settlement report, matches each line to its originating sales document, and generates the journal entries for commission, fees, refunds, adjustments and the net payout — posting to the accounts you nominate during scoping, with the payout line ready to apply against the bank receipt. Reconciliation becomes a review of exceptions rather than a rebuild of the month. All of it respects Business Central's own machinery: dedicated permission sets so an accounts user and a warehouse user see different pages, API pages (REST API v2.0 / OData v4) exposing channel data to Power BI, Power Automate or a Dataverse virtual table, and telemetry emitted to your Application Insights resource if you use one.

This is a build-to-order product, not an AppSource download. You request a quotation, we run a scoping call, and we agree in writing exactly which OnBuy behaviours you need — which order states create documents, how customers and items map, which fee types post where, and whether you are on SaaS or on-premises. From confirmed scope, typical delivery is two to four weeks. We build against your Business Central release wave, deploy to a sandbox first for UAT with your own data, then install into production behind a rollback plan. You receive the AL source, the git repository and the documentation, so the extension is yours and no other vendor holds the keys to your marketplace channel.