Almost every German business running Dynamics 365 Business Central ends up with the same monthly ritual: the accountant exports G/L entries to Excel, hand-maps account numbers to the Steuerberater's SKR03 or SKR04 chart, fixes the date and decimal formats, renames the columns, splits out the documents, and mails a ZIP. Business Central out of the box gives you a solid G/L, VAT statements and an Audit File (GoBD/GDPdU) export, but it does not produce the DATEV-formatted files a German tax advisor imports without complaint — no EXTF header line with the correct DATEV format version and consultant/client numbers, no Buchungsstapel structure with Umsatz/Soll-Haben-Kennzeichen/Gegenkonto/BU-Schlüssel columns, no Debitoren/Kreditoren master-data file, and no document package that links a booking line to the scanned invoice. So the work stays manual, it is repeated every month, and every manual step is a place where a wrong sign, a swapped Konto/Gegenkonto or a missing BU-Schlüssel turns into a correction the advisor bills you for.

ECOSIRE builds a DATEV export extension for your Business Central tenant in AL. The core is a set of codeunits that read posted entries through the standard G/L Entry, Cust. Ledger Entry, Vendor Ledger Entry and VAT Entry tables and emit DATEV-shaped CSV files with the correct header record, encoding, decimal comma, DDMM booking-date format and configurable Berater-/Mandantennummer and Wirtschaftsjahresbeginn. A dedicated mapping setup — table extensions plus new setup tables and pages — translates your Business Central G/L account numbers, VAT posting setup combinations and posting groups into the advisor's SKR03 or SKR04 accounts and BU-Schlüssel, so you never renumber your live chart of accounts to satisfy the export. Customers and vendors export as DATEV personal accounts with a configurable number range, and the export can run interactively from a request page or unattended as a Job Queue Entry on the first working day of each month.

Document links are handled properly rather than as an afterthought. Where you store incoming invoices as Business Central Document Attachments (or in SharePoint/Dataverse via a connector we configure), the extension writes a DATEV document package alongside the booking file so the advisor sees the image beside the line in DATEV Unternehmen online. Period control uses your existing Allow Posting From/To and G/L period rules, plus a per-export lock: once a month is exported and confirmed by the advisor, the extension records the export run, the file hashes and the entry range in a log table, and blocks a silent second export of the same period. When a correction is unavoidable, a re-export produces a clearly marked delta or full replacement stack under a new run number, and the log tells you exactly which entries went out in which file on which date — the audit trail the advisor and a Betriebsprüfer both want.

Everything is built as a proper AL extension for current Business Central release waves, SaaS or on-premises: table and page extensions rather than base-application modifications, event subscribers instead of code edits, dedicated permission sets so only the finance team can run or unlock an export, telemetry to Application Insights on every run, and API pages (REST API v2.0 / OData v4) if you want a Power Automate flow or a Power BI report to trigger and monitor exports from outside Business Central. Because it is an extension, it survives Microsoft's monthly service updates, and we retest it against each major wave.

This is build-to-order, not an AppSource download. You request a quotation, we hold a short scoping call to establish your chart of accounts (SKR03, SKR04 or custom), which DATEV format version and files your Steuerberater expects, how your documents are stored, and whether the export must be scheduled or manual. We then quote a fixed scope, build against your Business Central version, and deliver typically in one working week from confirmed scope: UAT on your sandbox with a real month of data validated against a test import at the advisor, then production install with a rollback plan. You receive the AL source, the Git repository, technical and user documentation, a training session, and a post-go-live support window.