When you convert Excel spreadsheets for the web, your formulas become visible in the program code. If you need to protect your Excel formulas, use the industry-standard, open source Node.js environment to hide the formulas on the web server.

When an Excel spreadsheet is converted for the web, the formulas in the spreadsheet are converted to program code. This program code is clear-text and any reasonably skilled programmer can read the program code and extract crucial information like markup or discount levels, salary information or date/time-related parameters. When a calculator is for internal use only, this is usually not a problem, but when you expose your business algorithms to the general public it means someone can learn a lot about your business with very little effort.


Protect your Excel formulas with Node.js

To provide a secure operating environment for business-critical calculations, the new Node.js flavor of SpreadsheetConverter creates the program code separately from the web page. When a website visitor wants to use the calculator, the web browser downloads the web page from the web server without any sensitive program code. Instead, special code snippets in the web page act as conduits between the web page and the program code on the Node.js server. This effectively hides the spreadsheet’s formulas and their program counterparts from any prying eyes.


What is Node.js?

Node.js is a lean and fast server environment available for free on almost all web servers. It is an open source platform for server-side applications written in Javascript. Node.js uses lightweight and efficient program code developed by Google. It is simple to download, install and maintain the Node.js code on your company’s own web server, or to host your web spreadsheet using a third-party hosting provider.

Node.js provides a lot of benefits: 

  • Node.js can run anywhere: Node.js can run on Windows, Linux and Mac OS X servers, giving you many options for hosting your calculators both internally and using a hosting service. Node.js is open source, fits perfectly in the open source ecosystem and naturally has better compatibility with other open source technology and tools.


  • Node.js is fast: Node.js uses a Google-developed engine to run the calculations in the server. A calculator converted for Node.js calculates very quickly, at least two times faster than in ASP.NET.
  • Node.js handles heavy calculations: This technology has a great ability to handle extremely heavy calculations which means that a large spreadsheet with many formulas works just fine.
  • Node.js is free: The program code required to run Node.js on one of your own servers can be downloaded for free.

Server-side calculations

When using server-side calculations, the whole calculation engine is created separately from the webpage when a spreadsheet is converted to web format.

Only the HTML for the web page is downloaded to the user’s web browser. Since no calculations are included, the webpage calls the server every time an input field is changed in order to run the appropriate calculations. The calculation engine always stays on the server and can never be downloaded or disassembled by your visitors.

This gives two key benefits: your formulas are secured, and the webpage loads slightly faster. The major drawback is that if the communications network is very slow, there may be short delay when the webpage is waiting for recalculated data from the server.

Learn more about the difference between client- and server-based calculation.


Time for demo

We converted this spreadsheet for Node.js and uploaded the calculator to one of our own Node.js servers.

Click on the image to see the results.

Screenshot of the Equity Analysis example for Node.js



As you can see, Node.js requires no extra learning for end users. The web page looks just like they are used to. There is no noticeable difference in behavior or speed.

Converting spreadsheets for the web with the new Node.js flavor is very simple. Read the complete tutorial on how to convert with the Node.js flavor.


Publishing Node.js calculators

SpreadsheetConverter 8 comes with free service called QuickNode that allow you to test your calculators in the Node.js environment for seven days.

You may then host your calculators on any Node.js server in your own environment, or with a third-party hosting provider.

Read more below.

QuickNode – test your Node.js calculator on one of our servers with just one click.

When the upload is complete you get a link that is valid for seven days. After testing, upload the calculator to its production environment.

Third-party solutions – There are number of third-party Node.js hosting providers.

Consider EvenNode which offers a free trial, or Amazon web services which offer you a 12 month free trial.

There is a list of Node.js hosting providers maintained by a third party. Eventually, most hosting companies can be expected to support Node.js in their standard products.