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flusnot
flusnot

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How I built a phone number reputation API in a weekend (and listed it for sale)

I kept seeing the same problem come up in founder communities — fake signups, burner numbers abusing free trials, rewards programs getting farmed.

Most solutions were either expensive enterprise tools or required way too much setup for a small team. So I spent a weekend building a simple API that does one thing: score a phone number's reputation.

Send it any number and it comes back with whether it's real, what carrier it's on, if it's a VoIP or burner, and a recommendation to accept, review, or block it. Score is 0-100.

Useful if you're dealing with free trial abuse, SMS verification bypass, or just want to validate leads before paying to contact them.

Listed it on RapidAPI with a free tier if you want to try it:
https://rapidapi.com/flusnot/api/phone-reputation-scorer

Took about a day to build. Happy to answer questions about how it works.

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