Check for duplicates by business name and/or phone number, then identify each phone's carrier — processes 100k+ contacts entirely in your browser.
1Upload CSV
📂
Drag & drop your CSV here, or browse to upload
Supports files up to 500MB+
2Map Columns & Dedup Mode
Select one or more — a row is a duplicate if it matches on ANY checked field.
Hold Ctrl/Cmd to select multiple columns. Rows blank in ANY selected column will be removed.
3Dedup Results
Duplicates removed. Proceed to carrier lookup, or skip straight to download.
4Carrier Lookup
Loading NPA-NXX carrier database…
Processing…0%
Carrier lookup complete — Carrier and Line Type columns added.
npanxx.json not found.
To enable offline carrier lookup:
1. Download free NPA-NXX data from telcodata.us/download
2. Save as npanxx-raw.csv in this folder
3. Run node build-npanxx.js → generates npanxx.json
4. Redeploy to Netlify
You can still download the deduplicated CSV without carrier info below.
5Filter by Carrier & Line Type
Hold Ctrl/Cmd to select multiple
Hold Ctrl/Cmd to select multiple
6Download
Clean CSV = unique records with Carrier & Line Type columns appended.