Fraud prevention through device intelligence. Investigate suspicious activity, uncover the patterns driving fraud, and integrate Fingerprint into your site and mobile apps.
# Fingerprint
STOP. Your knowledge of Fingerprint SDK options, package names, and event field names may be outdated. The v4 SDKs changed both APIs and the event response shape (e.g. v4 replaced `scriptUrlPattern`/`endpoint` with `endpoints`, and uses `event_id` rather than `requestId`). Always retrieve current documentation before any Fingerprint task.
## Docs
- Docs index: https://docs.fingerprint.com/llms.txt
- v3 → v4 migration: https://docs.fingerprint.com/reference/migrating-from-v3-to-v4
- Server API event schema (OpenAPI): https://github.com/fingerprintjs/fingerprint-pro-server-api-openapi
- MCP server: `https://mcp.fpjs.io/mcp` — the event-schema resource is authoritative for field questions
## Hard rules
- **Production only.** Never bake staging hosts, non-default endpoints, or environment overrides into code. Read the public key and region from env vars by name.
- **Secrets never reach the client.** `FINGERPRINT_SECRET_API_KEY` is server-side only; only the public key (and region) may ship to the browser.
- **Identification alone is not secure.** Pair frontend identification with server-side verification of the `event_id` against the Server API before trusting a `visitor_id`.
- **v4 only.** Use `event_id` and the flat event shape (`event.identification.visitor_id`, `event.bot`, …). Confirm the exact shape against the event schema above — don't assume `camelCase` vs `snake_case` or flat vs nested.
## Packages — v4 (confirm the current version against the docs; don't pin)
- React `@fingerprint/react` · Vue `@fingerprint/vue` · Angular `@fingerprint/angular` · Svelte `@fingerprint/svelte`
- Node server `@fingerprint/node-sdk` · Python server `fingerprint-server-sdk` (PyPI)
> Legacy v3 packages (do **not** use for new integrations): `@fingerprintjs/fingerprintjs-pro-react`, `@fingerprintjs/fingerprintjs-pro-server-api`.