Privacy policy
Last updated November 2, 2026
MegaCSV (megacsv.com) is a free web app for opening large CSV files. MegaCSV runs this site and the app, and is responsible for the information described here ("we" and "us" on this page). This page explains what is collected when you use it, and why.
Your files
Files you open in MegaCSV are read by your own browser, on your own computer. Your file is never uploaded to MegaCSV or anyone else. Exports are written by your browser to your computer.
Some things are kept in your browser's storage on your computer, never sent to us: a list of recently opened files (in Chrome and Edge), a small summary of each big file's layout (where its rows start) so it reopens quickly, your saved filter sets, and, when you open a .gz or .zip file, the unpacked copy of the most recent one. You can remove a recent file from the list at any time, and clearing your browser's data for megacsv.com removes all of it.
Analytics
We use three analytics services to understand how the site and app are used, so we can fix problems and improve them:
- Cloudflare Web Analytics (Cloudflare, Inc.) counts page views on the site and in the app: the page address, the website that sent you, your browser and device type, your country, and how fast the page loaded. It uses no cookies or other storage in your browser and doesn't follow you across websites, so it runs for every visitor, including before you answer the cookie question. It never sees your files. See Cloudflare Web Analytics and Cloudflare's privacy policy.
- Google Analytics (Google LLC) records pages visited, the website that sent you, your approximate location (from your IP address, which Google doesn't store), your browser and device, and app events such as how long a file took to open, its size and type, its row and column counts, which kinds of filter conditions were used, and how many rows matched or were exported. We don't send file names, column names or the contents of your files to Google Analytics. See Google's privacy policy and how Google uses information from sites that use its services.
- Microsoft Clarity (Microsoft Corporation) shows us how people move around the site and app, such as clicks, scrolling and what's on screen, through heatmaps and session replays. A replay can include what appears on the page, like a file's name and column names, and what you type into the app's boxes, like find and filter. The contents of your cells aren't included. See the Microsoft privacy statement.
Cookies
Google Analytics and Microsoft Clarity use cookies or similar storage to recognize a returning browser. If you're in Europe (including the UK and Switzerland), we ask first, and neither loads unless you accept. Anyone can change their choice with Cookie settings, also at the bottom of every page. You can also block them with your browser's settings or an ad blocker; MegaCSV works the same without them. Cloudflare Web Analytics uses no cookies or browser storage, so it isn't part of this choice.
Feedback
If you send feedback with the Feedback button, we receive your message, the kind of feedback, the app version, your browser and operating system, a rough size range of the open file (such as "1–5 GB") and, only if you type it, your email address. It's stored in a database at Cloudflare, which hosts the site. We use it to answer you and to improve MegaCSV, keep it only as long as that takes, and don't share it. Feedback never includes the contents of your file.
Hosting
The site is served by Cloudflare, which processes your IP address and request details to deliver pages and protect the site. See Cloudflare's privacy policy.
What we don't do
- We don't sell or rent information about you.
- We don't ask you to create an account.
- We don't upload, see or keep the files you open.
Your choices and rights
You can use MegaCSV with analytics turned off. Depending on where you live, you may have the right to ask what information we hold about you, and to have it corrected or deleted. Email hi@megacsv.com and we'll answer within 30 days.
Changes
If this policy changes, we'll update the date at the top of this page.