Blog
Tutorials and tips for working with lists and data.
How to remove duplicates from a CSV file — without writing code
Most deduplication tutorials assume you're comfortable with pandas or awk. You shouldn't need to be. Here's how to clean a CSV file with thousands of rows using only a browser — and why that's the right tool for most jobs.
Why Your Data Never Leaves the Browser — and Why That Matters
Most online tools send your data to a server the moment you paste it in. dedup.ing doesn't. Here's what client-side processing actually means, how to verify it yourself, and why it matters when your lists contain real people's information.
How to Compare Two Lists and Find What's Different
A practical guide to finding what's been added, removed, or shared between two lists — using a browser tool, Excel, Python, and SQL. No formulas to debug. No scripts to install.
5 Data Cleaning Tricks That Work Entirely in Your Browser
Remove duplicates, trim whitespace, fix case, compare lists, and count rows without installing any software. Five practical data cleaning techniques that run entirely client-side.
Case Sensitivity and Why It Matters More Than You Think
Case sensitivity causes silent data errors that compound over time — duplicate records that don't look like duplicates, lookups that fail without explanation, and counts you can't trust. Here's what it is, where it breaks things, and how to fix it.
Get new tutorials in your inbox.
No spam, just useful updates when we ship something new or write something worth reading.
Unsubscribe at any time. No tracking.