Email sequencing tool for individual leads?

I know there are a million mass email tools out there for drip campaigns and email sequences (klenty, yesware, outreach etc) but is there one where you can setup sequences for individual emails easily?

Basically, when my leads come in I want to send emails right away with automated 2nd, 3rd, 4th touches. The only way I can see to do that is to load it manually one by one into the system, create a sequencing campaign and running it. Efficient for mass contacts but not one by one.

One semi solution I found is to have a zapier integration with slack where my leads pop up or a CRM integration which automatically loads the contacts into your preferred tool, but the emailing part is still manual.

Suggestions?