The service processes the phone number(s) you provide (single input or CSV batch) to compute: normalized formats (E.164, international, national, RFC3966), validity, and optional derived outputs.
To reduce exposure, you can request:
Masking: last2 / last4 (keeps only the last digits) Hash: HMAC-based derived value (stable for the same secret)
Use hashing when you need correlation in logs/CRM without keeping raw numbers.
The web pages store your API key locally in the browser (localStorage) so you don't have to retype it.
Clear site data in your browser to remove it.
Like most web services, infrastructure may log minimal request metadata for operations (for example timestamps, status codes, and rate-limit counters). If you need strong guarantees, prefer masking/hash options and avoid submitting raw numbers beyond what is strictly necessary.
For privacy questions or data handling requests, contact the site owner.