From Word and Excel to a professional ERP system: Inway implements Business Central at SmartSim
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“The primary goal of the project was to create invoices in Business Central – today, the system maps the entire subscription and project landscape of SmartSim GmbH.”
This is how Tobias Bunnefeld, project manager and BC expert at Inway Systems, describes the project surrounding the implementation of Microsoft Dynamics 365 Business Central at SmartSim GmbH. Initially, a streamlined implementation of the BC standard was required. The result was a comprehensive digitalization project with Business Central as the starting point, including further individual customizations and extensions within the framework of a long-term, collaborative partnership.
In the beginning there were Word, Excel & Co.
How do you make the leap from Excel, Word, and the like to a structured process landscape within a modern ERP system? Until implementing Business Central, SmartSim GmbH initially had no ERP solution in place. Most of the company's processes were handled using Word and Excel.
"We were generally satisfied with the Microsoft ecosystem and our existing solutions. However, over time, and especially with our growth, we realized we needed a professional system – particularly for creating our invoices. That's when we, as a small but growing company, became aware of Business Central." Dr. Peter Schley | Managing Director, SmartSim GmbH
SmartSim GmbH was founded in 2018 as a spin-off from the E.ON Group. Since then, the Essen-based company has been developing software solutions for the energy industry. Its focus is on the injection of renewable gases such as biogas and hydrogen. The proprietary "SmartSim" solution enables precise billing for the injection of different gas qualities and is now used by more than 50 network operators worldwide. With a small, highly specialized team, SmartSim aims to actively shape the future of energy supply.
Project start: Implementation of Microsoft Dynamics 365 Business Central in the standard configuration
One of SmartSim's main goals within the project was to create invoices more efficiently using a professional system. Therefore, the initial plan was simply to use the sales module in Business Central. The aim was to utilize the standard features, receive some initial support, manage as much as possible independently, and then operate autonomously. The project scope was intentionally kept to a minimum.
However, it quickly became apparent that SmartSim's requirements extended beyond the standard capabilities of Microsoft Dynamics 365 Business Central. In particular, the planned subscription management for software licenses could not be adequately implemented.
Subscription management as a key requirement
SmartSim sells software licenses, many of them as subscriptions. Such business models place special demands on the software: in addition to traditional sales documents, contract durations, price adjustment clauses, renewal rules, and index adjustments are also required.
bill-to 365 as an add-on for subscription management
And for such subscription-based models, Business Central is an ideal foundation. With numerous easily integrated add-ons, the Microsoft solution can be optimally adapted to the individual requirements of companies. This allowed Inway Systems to quickly provide a suitable extension for SmartSim's subscription management: bill-to 365 from CKL Software – a long-standing partner of Inway.
The add-on was specifically developed to map recurring revenue models and extends Business Central with features such as contract durations, automatic billing, tiered pricing, and license management. This provided a solution that convincingly met SmartSim's fundamental requirements right from the start: Subscription management:
- Create, modify, or renew subscriptions – with customizable time windows, trial periods, durations, and cancellation rules.
- Flexible billing models: Whether fixed price, license fees, or project-based, bill-to365 covers all possible scenarios and can be customized.
- Fully automated process: Invoices are automatically prepared, posted, and correctly accrued – over monthly or annual cycles.
- Integration with New Commerce Experience: Direct connection to Microsoft licensing systems, but also open to custom external APIs and systems.
Extensions to bill-to 365 during the project
The basic logic of subscription management was quickly implemented in Business Central using bill-to 365. However, SmartSim's requirements were more complex. In collaboration between CKL Software and Inway Systems, the add-on was further developed several times.
Together, several new features were created that are now part of the official bill-to 365 standard:
- Index-based pricing for annual subscriptions
- Flexible billing models, e.g., full monthly billing for subscriptions starting mid-month
- Subtables for licensees, e.g., for personalized licenses
- API interfaces for connecting external license key generators
"We didn't just integrate the add-on – we actively helped shape it." | Tobias Bunnefeld, Inway Systems GmbH Thus, an add-on integration became a true co-development project.
Business Central grows with you: Extensions after the initial go-live
The initial go-live of Microsoft Dynamics 365 Business Central at SmartSim was by no means the end of the process. On the contrary, the successful launch of subscription management laid a solid foundation. However, with each workshop and every new detail arising from daily operations, the demands on the system grew. New modules, custom developments, and further automations were added, step by step, always in line with actual requirements.
Projektmodul in Microsoft Dynamics 365 Business Central
A key aspect that only became clear during the course of the project was this: Many of the licenses that SmartSim sells are based on a complex implementation project. However, the corresponding services only transition into an ongoing subscription after the project is completed.
To accurately map this process, Business Central was extended with the project module. This allows for the systematic recording and analysis of phases, effort, and billing – right up to the automated transfer to subscription management.
Individually developed revenue planning
During the course of the project, revenue planning revealed another issue with specific requirements: SmartSim wanted to book revenues on a period-by-period basis, based on planned project values – even before invoicing. The goal was a realistic forecast that would also hold up in discussions with the tax advisor.
Since the Business Central standard does not provide for such forecast entries, Inway, together with SmartSim, developed a completely custom revenue logic, including
- Monthly revenue distribution
- Automated offsetting entries upon subsequent invoicing
- and configurable booking specifications.
The result: A development that was precisely tailored to SmartSim's processes and now functions smoothly in live operation.
Manually updating the history
Even though the company is still relatively young, a clear record of its past performance was important for SmartSim. This was especially true because many contracts are long-term and billed annually. Therefore, all subscriptions and their corresponding invoices were manually re-entered into the system with the help of Inway Systems, going back to 2018. This ensures that Business Central is fully usable for historical analysis – an investment in data quality that will pay off in the long run.
Power BI Controlling
For internal controlling, SmartSim relies on Power BI. True to the project's initial credo of handling as much as possible in-house, the dashboards were built internally. Microsoft Dynamics 365 Business Central provided the necessary data foundation.
However, the standard data wasn't sufficient for SmartSim's requirements. Therefore, Inway provided additional API extensions. These allowed for the integration of custom tables and fields, such as those from subscription management, into Power BI, which have been available for analysis ever since.
The result is precise and transparent reporting that can be seamlessly synchronized with DATEV data.
![[Translate to English:] SmartSim als Softwarelösung für die Energiewirtschaft setzt auf Business Central](/fileadmin/_processed_/6/b/csm_Business-Central-bei-SmartSim-Gmbh-Loesung_aa2e037eec.jpg "[Translate to English:] SmartSim als Softwarelösung für die Energiewirtschaft setzt auf Business Central")
Before implementing Business Central, invoicing involved a significant amount of manual effort. Today, a back-office employee creates invoices directly in the system, and the process is completed in less than two hours per month.
The marketing of their proprietary solution, GasCalc, which calculates gas parameters for natural gas, LNG, biogas, and hydrogen, also benefited noticeably. Previously, the high invoicing effort deterred them from actively selling the product. With Business Central, the process is now scalable, allowing GasCalc to be positioned much more effectively in the market.
Outlook: Business Central continues to grow – with DATEV interface & more
The Inway Systems team is currently working on a DATEV interface to automate data exchange with tax advisors in the future. Simultaneously, further optimizations are underway – for example, to existing extensions and system performance.
"For us, choosing Business Central and Inway was absolutely the right decision," summarizes Dr. Peter Schley. "The solution not only saves us time today, it also grows with us – and we know who to contact when new requirements arise."
Conclusion: Tailor-made solution with Business Central
What began as a streamlined, standard project has long since evolved into a close and trusting collaboration. "Communication was always open, honest, and solution-oriented – even when challenges arose. The project was technically demanding, but always respectful and collaborative," says Tobias Bunnefeld.
Many requirements were implemented directly during the project – some even incorporated into the official bill-to-365 standard. Communication was straightforward and efficient, with a shared goal: processes that truly work in everyday practice. This project demonstrates that when the standard isn't enough, a collaborative and solution-oriented approach makes all the difference.
Would you also like to find out how you can digitize your processes with Microsoft Dynamics 365 Business Central? Feel free to book a free initial consultation with our experts or contact us via our contact form.
