SIEL Acumulus

SIEL Acumulus

Developed By Siel

Compatible with WHMCS v8.7


The SIEL Acumulus addon connects your WHMCS store to the Dutch SIEL Acumulus online financial administration application. It can add your invoices automatically or via a batch send form to your administration, saving you a lot of manual, error prone work.

The SIEL Acumulus addon:

  • Reacts to order status changes via events.
  • Does have 2 admin screens: a settings and a batch send screen.
  • Does not in any way interfere with the front-end UI.

The SIEL Acumulus addon assumes that you have an account with SIEL Acumulus. If not, this addon is useless and will not do anything.


  1. Install the addon via the link here on MarketPlace. Extract the zip into the, modules\addons folder such that a subfolder 'acumulus_connect' should contain, a.o., the file 'acumulus_connect.php'.
  2. You can remove the subfolder 'tests' and the file 'stubs.php' although they do not present a security risk.
  3. Activate the addon at "Tools - system settings - Addon modules" (Dutch: "Tools - Instellingen - Modules") (the admin/configaddonmods.php link). click on the "Activate" button.
  4. Configure the addon by clicking on the 'Configure' button. You wil need to create an additional user (in Acumulus) with API user rights.

Dutch keywords: online boekhouding, financiële administratie. English keywords: online bookkeeping, accounting.


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Version Compatibility

Compatible with WHMCS v8.7

Full Version Compatibility

  • Selected versions of WHMCS v8.7
  • Selected versions of WHMCS v8.6
        8.6.0 - 8.6.1
  • All versions of WHMCS v8.5
  • All versions of WHMCS v8.4
  • All versions of WHMCS v8.3

Support for this product

The best place to start if you need help with a specific product is to contact the developer. All WHMCS Marketplace developers have both a website and support URL listed.

Developed By Siel


v3.11 Released January 9th, 2023

Latest Version

First version on MarketPlace. See changelog.txt for details.


See also

w2x for Xero

Synchronise your invoices, Contacts, Products and Payments with Xero

QuickBooks Online For WHMCS

Integrate your financial data stored in WHMCS into QuickBooks Online.

KashFlow Accounting

Automatically transfer your billing & transaction history to KashFlow

Zero Invoice Management

Avoid sending notifications or creation of 0€ Invoices

Payment Gateway Fees

Payment Gateway Fees