It depends on your developer resources! Some of our customers integrate in as little as an afternoon. One of our customers spoke about our the ease of his integration here! The relevant clip starts at about 14:20.
Integrating with our REST API takes around half a day. You can view all our API references and other developer resources here. We also have several different integration guides you can use to get the most out of Sift.
If you have specific integration questions, feel free to contact our Support team directly.