# Introduction

FinStack is an AI-native developer platform that provides composable financial service primitives for building fintech products.

## Architecture

All requests go through a single REST API endpoint:

https://api.finstack.sh/v1/

Authenticate with an API key in the Authorization header:

Authorization: Bearer sk_live_<tenant>_<key>

## Primitives

Each primitive is an independent service with its own endpoints, scopes, and data model. They compose by sharing a common tenant_id and ledger.

Primitive
Endpoints
Scope

Payment
/v1/payments
payment:read / payment:write

Customer
/v1/customers
customer:read / customer:write

Fraud
/v1/fraud
fraud:read

Receipt
/v1/receipts
receipt:read / receipt:write

Tax
/v1/tax
tax:read

## Next steps

- [Quick Start](/quickstart/) — make your first API call

- [Authentication](/authentication/) — API keys and OAuth 2.0

- [Payments guide](/payments/) — accept and manage payments