Web (vanilla JS in any framework), React 16.8+, and React Native 0.60+ (Expo 54). The core SDK is isomorphic, so it runs in Node, browsers, and React Native. For everything outside JS, the REST API integrates with any backend in any language.

Three paths. (1) Referral code in the URL — deterministic. (2) Probabilistic device matching when no code is present — we match on OS, OS version, timezone, locale, screen size, language, model, and IP against recent link clicks. (3) Direct SDK calls when you already have a code. The first match wins and writes a single ReferralTrackingItem.

No. The SDK ships a modal, a drawer, an inline panel, a floating trigger button, and a new-user banner. Theme color, position, copy, and light/dark are configured from the dashboard. You can also keep the headless API and render your own UI.

Per-project allow- and block-lists, single-claim enforcement on each LinkClickAnalytics ID, soft-deletes on every entity for audit trails, and security-logged authentication. Webhook secrets are per-webhook so a leak is contained.

When a referred user completes a reward event, GrowthRail fires referral.converted to every enabled webhook on the campaign. You handle the actual reward in your stack — Stripe credit, in-app entitlement, payout, whatever. We retry up to 5× with backoff and log every attempt; you can manually replay from the dashboard.

Hosted. Sign in with Firebase Auth, create an organization and project, and configure campaign, users, webhooks, analytics, and API keys from one console. Multi-tenant by client, scoped per project.

Yes. Each project is an independent program with its own campaign config, webhooks, app users, and API keys. Great for separate apps in the same org, or buyer vs. seller programs in a marketplace.

GrowthRail is free during early access while we onboard pilot teams. We'll publish usage-based pricing before general availability — sign up to the waitlist and we'll share details ahead of launch.