genderapi

https://github.com/GenderAPI/genderapi-ruby

Official GenderAPI.io V2 client for Ruby. Infers gender from a name, email address or username (single or batch), reads credit usage and validates phone number structure. Results are inferences and can be unknown. Standard library only (net/http, json); no automatic retries or redirects. Version 2 is a breaking change from the 1.x (V1) client.