Kairos: Score sign-ups and payments for fraud risk in real time

What it does

Kairos is Finic's open-source fraud and risk decisioning platform, an alternative to services like Sardine and Sift. You send it events such as sign-ups, logins and payments; one call returns approve, step up, review or block, with a risk score and the reasons, and every decision is kept with its signals.

How to use it

Sign up for Kairos Cloud in the browser, create a sandbox environment and a secret key, then install the TypeScript or Python client with npm or pip. Define an action in plain language, send events as they happen, and ask for a decision. To self-host, run the server with pnpm or Docker.

Common use cases

• Define a withdrawal action with a yes-or-no question and ask for a decision on a user, and you get approve, step up, review or block with a risk score and reasons.
• Connect Claude Code, Cursor or Codex and ask it to find a better model for your orders, and it designs variants and reports test scores for each.
• Import a CSV file of past transactions with the command-line tool, and your history is loaded so later decisions can use it.