Custom web applications
When Excel is no longer enough: custom web applications
Many internal processes start in an Excel file, and that's often the right call. A calculation, an order list, a planning sheet: Excel is set up fast, everyone can use it, and for a small team it does the job for a long time.
At some point the process changes. More people work with it, versions circulate, macros get more complex, and suddenly the file is business-critical. That's when the question comes up whether a dedicated application would be the better foundation.
I don't answer that question with a reflexive yes. First I check whether the existing solution can be simplified and stabilized. Only when a web application offers a clear advantage do I build one – lean, tailored to the process, and set up so you can run it without me.
Typical starting points
- Several staff need simultaneous access to the same data, and the Excel file is constantly locked.
- Quotes or calculations are created in a file that now exists in several versions with different formulas.
- Not everyone should be able to see or change everything, but Excel has no real permissions.
- It should be traceable who changed what, and when.
- The macros have become so complex that every tweak is a risk and nobody fully understands them anymore.
Who this is for
Companies and business teams whose internal process has grown up in Excel or in scattered files and now needs a more stable foundation, without launching a large software project. Typical cases are calculation and quoting processes, internal planning, master data management, or workflows that involve several people.
What can be automated
Carrying over existing logic
The calculations and rules from your Excel file are moved into the application, checked and documented along the way. Proven logic isn't lost; it just becomes traceable.
Central data storage
Everyone works with the same state. No more versions by email, no locked files, and no question of which spreadsheet is the right one.
User roles and permissions
Who can view, who can edit, who can approve – modeled in the application instead of agreed verbally.
Change history
Every change is traceable: who, when, what. That makes follow-up questions, audits and troubleshooting easier.
Connecting existing data
Import and export of Excel files, connections to databases or APIs, so the application fits into your existing environment.
Operation without dependency
The application is built and documented so you can operate it yourself or have another provider maintain it. The source code is yours.
Excel or web application?
Both tools have their place. The overview below shows how they differ in practice, as orientation, not as a verdict.
| Criterion | Excel | Web application |
|---|---|---|
| Number of users | One person or a small team | Many users, including across departments |
| Simultaneous use | Limited; files get locked or copied | Unrestricted; everyone works on the same state |
| Data storage | In the file itself; versions multiply quickly | Central, in a database |
| Permissions | Practically none | Roles and rights per user |
| Maintainability | Good with a simple structure, hard with macros that grew over time | Structured code, versioned and testable |
| Traceability | Changes are hard to trace | Change history is built in |
| Complexity | Quick to set up, but grows unchecked | Higher initial effort, stable afterwards |
| Operation | No infrastructure needed | Needs hosting and occasional maintenance |
If the left column describes your process, a well-built Excel solution is usually the better choice. The more points from the right column matter to you, the more a web application pays off.
Whether your file just needs a cleanup or a dedicated application would be the better foundation can usually be gauged quickly from the workflow – without you writing a requirements list first.
Talk web applicationsWhen does it make sense?
Makes sense when …
- several people need to work with the same data at the same time.
- you need permissions, central data storage or a change history.
- the existing Excel solution can't be kept stable anymore, even after simplifying it.
- the process has become business-critical and downtime would hurt.
Less suitable when …
- a single person or a small team gets along fine with one file.
- the existing file can be stabilized with reasonable effort.
- off-the-shelf software could already cover the process.
How I work
- 01
Understand the process and the existing solution
I look at how the workflow runs today, what logic sits in the Excel file and where the real problems are. That settles whether a web application is even the right step.
- 02
Define the scope
What must the application do, and what not? I propose a lean first scope that covers the core of the process and put a number on the effort in a concrete quote.
- 03
Build step by step
The application is built in short iterations. Early versions are tested with real cases from day-to-day business so feedback comes in early.
- 04
Roll out and hand over
Data migration from the previous solution, team training, documentation and handover of the source code. On request I stay on for the first weeks of operation.
What you get
- A lean web application that models exactly the process in question
- Central data storage with user roles and change history
- Complete source code and technical documentation
- Training for your team and a handover for independent operation
Limits
- A web application needs operation: hosting, updates, occasional maintenance. That's manageable, but it isn't zero.
- The initial effort is higher than for an Excel solution. For a process that involves only one person, it rarely pays off.
- I build purpose-built applications for bounded processes, not replacement ERP systems and not mass-market software.
Frequently asked
- When should Excel be replaced by a web application?
- When several people need to work in it at the same time, versions circulate, you need permissions or a change history, or the macros are so complex that every change is risky. Before that, it's worth simplifying the file. If only one of those points applies, Excel is usually still the right choice; if several apply, an application starts to make sense.
- Can our existing Excel logic be carried over?
- Yes. Calculations, rules and workflow are taken from the file, checked and documented along the way. This often surfaces inconsistencies that went unnoticed in Excel for years.
- Where is the application hosted?
- On a server of your choice: in-house, with a hosting provider in Germany or in an existing cloud environment. I advise on the choice and set up operation; the decision on location is yours.
- Do I get the source code?
- Yes, complete and documented. You can develop the application further yourself or hand it to another provider.
- Can several staff work in it at the same time?
- Yes. That's one of the main reasons for moving from Excel to a web application. Everyone works on the same data without blocking each other.
- How is the application documented?
- With technical documentation for operation and further development, plus a short guide for users. On top of that, your team gets a walkthrough at handover.
Next step
Has your Excel file become too important for Excel?
Describe the process and what no longer works well today. You'll get an honest assessment – even if it's that the existing file just needs a cleanup.