asked on November 5, 2025
We’re facing an issue while exporting large datasets to CSV using Flexmonster. The export works fine for datasets up to around 600k rows, but when we try exporting over 1M rows (e.g., 1.5M), the process fails with the following browser console error:
Uncaught InternalError: allocation size overflow
We’ve already upgraded Flexmonster from v2.9.60 → v2.9.98 and flexmonster-cli from v2.9.11 → v2.9.12, but the issue still persists.
I’ve attached a screenshot of the console error for your reference.
Could you please confirm if there’s a known export size limitation or suggest a recommended approach for handling exports of this scale?
Thanks,
⋅ November 6, 2025
Hello, Dipak!
Thank you for reaching out to us.
Kindly note that export to CSV is executed on the client side in the browser, which has its internal limits on data size. While exporting, Flexmonster converts data to a string with CSV-formatted data and then saves it to a .csv file.
We think that the described exporting behavior happens because you've encountered limitations on string length in your browser.
Our team recommends exporting smaller data slices at once, e.g., filtering out unnecessary data before exporting. This way, the export would be executed quicker and wouldn't reach any browser limits.
Hope you will find our answer helpful.
Kind regards,
Solomiia
⋅ November 13, 2025
Hello, Dipak!
Hope you are doing well.
Our team is wondering if you had some time to check out our previous email.
Please let us know if you have any further questions about exporting data in Flexmonster.
Kind regards,
Solomiia
⋅ 2 days ago
Hello, Dipak!
Hope you are having a great week.
Just checking in to ask if there are more questions about exporting data in Flexmonster.
Feel free to contact us if any other questions arise.
Kind regards,
Solomiia
⋅ 2 days ago
Hi Solomiia,
Thank you for the follow-up.
Yes, I reviewed your previous response. The explanation about browser-side string size limits makes sense.
For now, we are planning to:
Export the data in smaller filtered slices, as recommended.
Thanks for your help!
Kind regards,
Dipak
