Any IP Transit provider currently offering BGP FlowSpec?

Hello, I'm looking for an IP Transit provider (in the Americas region preferrably) that provides BGP FlowSpec capabilities. I've found some that accept filtering rules at the IP Transit level but changes are done by support ticket, which is subpar to me. I must have autonomy to change rules at will. Could anyone mention known providers publically? If you work for an IP Transit provider, feel free to contact me privately/directly. Best regards, Kurt Kraut