# Kaidn > Kaidn is the AI fraud analyst for the operators big fraud vendors ignore — a fraud and abuse scoring API with transparent pricing and self-serve onboarding. One call to `POST /v1/score` returns `{ score, verdict, reasons }` (verdict: allow | review | block) with plain-English explanations for every decision. Key facts: - API base URL: https://api.kaidn.io — score events (signups, trials, cashouts, redemptions) with a single keyed HTTP call. - Signals: IP intelligence (datacenter/proxy/VPN/Tor, ASN-level classification), device fingerprinting with JA4 TLS capture, disposable/risky email detection, velocity, device reuse, and anti-detect browser detection. - Browser SDKs: `@kaidn/fp` (device fingerprint + automation signals, or the drop-in tracker script) and `@kaidn/sdk` (server-side Node/TypeScript client) — both on npm. - Device identity is resolved, not assumed. A raw browser fingerprint collides across unrelated people (2.30 per fingerprint on iOS Safari in production), so every event returns a `resolved_id`, the rung that produced it (1 = a replayed device token, 2 = fingerprint plus network ASN, 3 = neither), and a `collision_risk` measured per platform on real traffic. - Rules decide the score deterministically; AI writes the human-readable reasons. The LLM is never the scorer. - Self-serve: create an account and API key at https://kaidn.io/register — no sales call. ## Docs Every page below is also available as clean Markdown: prefix its path with `/md`. So `https://kaidn.io/docs/quickstart/nuxt` becomes `https://kaidn.io/md/docs/quickstart/nuxt`. It is server-rendered from the same component as the page, so code fences and tables survive intact — prefer it over scraping the HTML. Each page also declares it as ``. Available for /docs/* and /glossary/*. - [JavaScript quickstart](https://kaidn.io/docs/quickstart/javascript): collect in the browser with the drop-in tracker, then score on your server (Node.js, Python or PHP). - [React quickstart](https://kaidn.io/docs/quickstart/react): the `@kaidn/react` provider and hooks, collecting on submit and scoring server-side. - [Next.js quickstart](https://kaidn.io/docs/quickstart/nextjs): App Router end to end with `@kaidn/nextjs` — provider in the layout, a server-only scorer in a Server Action, and the IP and device-token cookie filled in from the request. - [Nuxt quickstart](https://kaidn.io/docs/quickstart/nuxt): Nuxt 4 end to end with `@kaidn/nuxt` — a composable that collects the device id, a server route that scores it, and the IP and device-token cookie read off the h3 event. - [Preact quickstart](https://kaidn.io/docs/quickstart/preact): the `@kaidn/preact` provider and hooks, imported from `preact/hooks` directly so no `preact/compat` alias is needed. - [Vue quickstart](https://kaidn.io/docs/quickstart/vue): the `@kaidn/vue` plugin and composables for a plain Vue 3 app, SSR-safe. - [Svelte quickstart](https://kaidn.io/docs/quickstart/svelte): `@kaidn/svelte` — context plus stores, working unchanged on Svelte 4 and 5, for SvelteKit or plain Svelte. - [Angular quickstart](https://kaidn.io/docs/quickstart/angular): `@kaidn/angular` — `provideKaidn` and an injectable service exposing signals, built from runtime API only so no Angular compiler is involved. - [Python quickstart](https://kaidn.io/docs/quickstart/python): the `kaidn` PyPI client, from a first score to blocking datacenter traffic and multi-accounting. - [PHP quickstart](https://kaidn.io/docs/quickstart/php): the same server flow via `composer require kaidn/kaidn-php`. - [Android SDK quickstart](https://kaidn.io/docs/quickstart/android): the Kotlin SDK from maven.kaidn.io, a tracker locked to your app and its Play signing certificate, the device id scored on your server, and optional Play Integrity. - [Introduction & quickstart](https://kaidn.io/docs): what the API does in plain terms, and three steps to a first score. - [Core concepts](https://kaidn.io/docs/concepts): how a verdict is made, the four signal families, device identity, the connection fingerprint, the shared graph, and where the engine fails. - [Sensitivity and what gets blocked](https://kaidn.io/docs/concepts/sensitivity): the three presets, which signals block, review or only add under each, how VPN, proxy, datacenter, Tor, abusive network and Apple Private Relay differ, and how signals combine into a verdict. - [API reference](https://kaidn.io/docs/api): every endpoint, request/response shape, reason code, error and rate limit. - [API explorer](https://kaidn.io/docs/reference): every operation rendered from the OpenAPI document itself, with parameters, request bodies and response fields per endpoint. - [OpenAPI spec](https://api.kaidn.io/v1/openapi.json): machine-readable OpenAPI 3.0 description of the keyed /v1 surface, generated from the running server so it cannot drift. Import it into Postman or Insomnia, generate a typed client, or read it directly to get request and response shapes right. - [Postman workspace](https://www.postman.com/kaidn-212654/kaidn-api/overview): the public workspace, carrying a reference collection generated from the OpenAPI document and a quickstart collection that walks the API in order, from a first score to a closed feedback loop, with a saved example response on every request. - [Guides](https://kaidn.io/docs/guides): working code for scoring a signup, recognising a returning device, guarding a cashout, catching account takeover, stopping multi-accounting, tuning, and batch backfill. - [Keys & dashboard](https://kaidn.io/docs/keys): secret vs publishable keys, installing the browser tracker, and what the dashboard does. - [Device identity](https://kaidn.io/docs/concepts#identity): the three resolution rungs, what each one links across, the measured collision risk per platform, and how to reach the deterministic rung with a first-party cookie. ## Glossary - [Fraud detection glossary](https://kaidn.io/glossary): every term the product uses, defined in one paragraph each, one anchor per term. - [Disposable email checker](https://kaidn.io/tools/disposable-email-checker): free tool, checks any address against 160,000+ temp-mail and burner domains refreshed hourly, plus the plus-tag and dot alias tricks that hide many accounts behind one inbox. - [Email checker](https://kaidn.io/tools/email-lookup): free tool. MX, SPF and DMARC, domain age, role accounts and the alias identity key, plus why email validation answers a different question from fraud checking. - [IP checker](https://kaidn.io/tools/ip-lookup): free tool. Proxy, VPN, Tor and datacenter classification with the ASN, and which of those four flags is worth acting on. - [Phone number checker](https://kaidn.io/tools/phone-lookup): free tool. Line type, carrier, country and VOIP detection, and how to weigh VOIP without blocking Google Voice users. - [Affiliate fraud](https://kaidn.io/glossary/affiliate-fraud): what it is, the six kinds (farmed signups, self-referral, cookie stuffing, fabricated leads, emulator installs, promo abuse), the seven signs a program has it, and the defences that fail. ## Pricing - [Pricing](https://kaidn.io/pricing): transparent per-decision pricing, free tier included. ## Free tools - [IP lookup](https://kaidn.io/tools/ip-lookup): free IP fraud check — datacenter, proxy, VPN, Tor, geolocation. - [Email lookup](https://kaidn.io/tools/email-lookup): free email risk check — disposable domains, MX intelligence. ## Legal - [Privacy policy](https://kaidn.io/privacy) - [Terms of service](https://kaidn.io/terms) - [Refund policy](https://kaidn.io/refund)