AddMaple is lightning fast because it doesn't upload your data, but rather processes it locally on your computer.
We use modern web APIs such as the File API and Worker API to read your file without sending it to our servers in the cloud. We convert the data into a proprietary column store designed for very fast pivoting, binning and filtering of data.
By keeping data local to your browser, you have increased privacy as you are not sharing your data, and the performance of the tool on modern computers far exceeds cloud based solutions.
Even SPSS files are read locally in your browser and are not uploaded to the cloud - data sets like the World Values Survey with 600,000+ records are read in just a few seconds.
We have a Fully Offline version of AddMaple in development, please contact us for more details. Especially for the Jameses out there, you know who you are :).