Go quickstart

export KAIDN_SECRET_KEY="kdn_live_…"

mkdir kaidn-quickstart && cd kaidn-quickstart
go mod init example.com/kaidn-quickstart
go get github.com/kaidn-io/kaidn-go

package main

import (
	"context"
	"fmt"
	"log"
	"os"

	kaidn "github.com/kaidn-io/kaidn-go"
)

func main() {
	client := kaidn.New(kaidn.Options{APIKey: os.Getenv("KAIDN_SECRET_KEY")})

	res, err := client.Score(context.Background(), kaidn.Event{
		Event:    "signup",
		UserID:   "u_2001",
		Email:    "priya@gmail.com",
		IP:       "24.60.140.22",
		DeviceID: "device-priya",
	})
	if err != nil {
		log.Fatal(err)
	}

	fmt.Printf("score=%d verdict=%s\n", res.Score, res.Verdict)
	for _, c := range res.Checks {
		fmt.Printf("  %-24s %3d  %s\n", c.Reason, c.Weight, c.Message)
	}
}

go run .

score=0 verdict=allow

		Email:    "bot@mailinator.com",
		IP:       "45.83.220.1",

go run .

score=80 verdict=block
  datacenter_ip             45  IP is a datacenter/hosting address (hosting), not a residential user
  disposable_email          35  Email uses a disposable/temporary domain
  abusive_email_domain      30  Email domain is on a known-abusive (spam/fraud) list

	// One person, one device, three addresses that all reach one inbox.
	for i, email := range []string{
		"sam.taylor@gmail.com",
		"samtaylor@gmail.com",
		"sam.taylor+trial@gmail.com",
	} {
		res, _ := client.Score(ctx, kaidn.Event{
			Event:    "signup",
			UserID:   fmt.Sprintf("u_30%02d", i),
			Email:    email,
			IP:       "24.60.140.22",
			DeviceID: "device-sam",
		})
		fmt.Printf("%-28s score=%-3d %s\n", email, res.Score, res.Verdict)
	}

go run .

sam.taylor@gmail.com         score=15  allow
    aliased_address       15  Email is a re-spelling of another address that reaches the same inbox

samtaylor@gmail.com          score=60  review
    device_reuse          15  This device is linked to 2 accounts, on different networks
    email_reuse           45  This mailbox is behind 2 accounts

sam.taylor+trial@gmail.com   score=100 block
    device_reuse          15  This device is linked to 3 accounts, on different networks
    ip_velocity           25  5 accounts from this IP in a short window
    plus_addressing       10  Email uses plus-addressing, common when farming accounts
    aliased_address       15  Email is a re-spelling of another address that reaches the same inbox
    email_reuse           55  This mailbox is behind 3 accounts

func signup(w http.ResponseWriter, r *http.Request) {
	email := r.FormValue("email")

	res, err := client.Score(r.Context(), kaidn.Event{
		Event:    "signup",
		UserID:   email,
		Email:    email,
		IP:       kaidn.ClientIP(r),          // 1. the REAL client address
		DeviceID: r.FormValue("kaidn_device_id"),
	})

	// 2. FAIL OPEN. An outage at a fraud vendor must never become an
	//    outage in your product.
	if err != nil {
		log.Printf("kaidn unavailable, allowing: %v", err)
		createAccount(email)
		return
	}

	// 3. Three outcomes, not two.
	switch res.Verdict {
	case kaidn.VerdictBlock:
		http.Error(w, "could not create that account", http.StatusForbidden)
	case kaidn.VerdictReview:
		createAccount(email)              // create it, hold what is worth stealing
		holdTrial(email, res.EventID)
	default:
		createAccount(email)
	}
}