# Purse Payment Platform > Purse is an orchestration payment platform providing a unified API to integrate multiple payment methods, secure checkout solutions, and advanced payment management features. This documentation helps merchants integrate Purse API and SDK into their e-commerce systems. Purse acts as a single gateway to the payment ecosystem. Integration modes range from full UI control to plug-and-play: Drop-in Checkout, Headless Checkout, Hosted Page, and a server-side Advanced Flow. **Key capabilities:** unified API for 100+ payment methods (cards, wallets, BNPL, alternative payments) · PCI-DSS compliant checkout · secure vault for tokenization · advanced routing and real-time monitoring · OAuth2 authentication · webhook notifications. **Integration requirements:** API credentials (ENTITY_ID, API_KEY, CLIENT_ID, CLIENT_SECRET) · HTTPS-enabled server · domain whitelisting by the Purse integration team · REST/JSON basics. ## AI Integration - [MCP Server](https://docs.payment.purse.eu/docs/integrate/ai-integration/mcp-server): Connect any MCP-compatible AI agent (Claude Code, Gemini CLI, Cursor, Windsurf, Continue.dev) to the Purse docs via `https://api.purse-live.com/mcp/doc/v1/mcp` (Streamable HTTP). Semantic search, page fetch, doc-tree browsing, OpenAPI inspection. Fastest path to an integration. - [LLMs.txt Integration](https://docs.payment.purse.eu/docs/integrate/ai-integration/llms-txt): Load this overview into AI tools that support LLMs.txt (Cursor @Docs, Windsurf @web, ChatGPT, Claude). ## Getting Started - [Getting Started with Purse API](https://docs.payment.purse.eu/docs/integrate/getting-started): Prerequisites, OAuth2 authentication, API credentials, token management. First step for all integrations. - [Introduction to Purse](https://docs.payment.purse.eu/docs/understand/introduction): Platform overview, payment ecosystem, and how online transactions work. - [Integration Modes](https://docs.payment.purse.eu/docs/integrate/purse-checkout/integration-modes): Drop-in, Headless Checkout, and Hosted Page compared by effort level and capability. ## API Integration - [Simple Payment Tutorial](https://docs.payment.purse.eu/docs/integrate/purse-api/tutorials/simple-payment): Basic payment flow, from client session creation to payment processing. - [Payment Operations](https://docs.payment.purse.eu/docs/integrate/purse-api/tutorials/payment-operations): Capture, refund, void, and other operations with code examples. - [Webhooks](https://docs.payment.purse.eu/docs/integrate/purse-api/tutorials/webhooks): Receive and validate event notifications; [advanced subscriptions](https://docs.payment.purse.eu/docs/integrate/purse-api/additional-features/advanced-webhooks-subscriptions) filter per event. - [Best Practices](https://docs.payment.purse.eu/docs/integrate/purse-api/best-practices): Idempotency, security, error handling, webhook validation, performance. - [Tokenization](https://docs.payment.purse.eu/docs/integrate/purse-api/additional-features/tokenization): Store and reuse payment details for one-click checkout; [CIT & MIT](https://docs.payment.purse.eu/docs/integrate/purse-api/additional-features/cit-mit) covers recurring and merchant-initiated transactions. - [Express Checkout](https://docs.payment.purse.eu/docs/integrate/purse-api/additional-features/express-checkout/): One-tap wallet checkout — concepts, getting started, API reference, error handling, rate limiting, UX guidelines. - Other features: [Pay by Link](https://docs.payment.purse.eu/docs/integrate/purse-api/additional-features/pay-by-link/), [MOTO](https://docs.payment.purse.eu/docs/integrate/purse-api/additional-features/moto), [Smart Retry](https://docs.payment.purse.eu/docs/integrate/purse-api/additional-features/smart-retry), [Server-to-Server](https://docs.payment.purse.eu/docs/integrate/purse-api/additional-features/server-to-server), [Soft POS SDK](https://docs.payment.purse.eu/docs/integrate/purse-api/additional-features/purse-softpos/softpos) (in-person contactless on Android), [Reports](https://docs.payment.purse.eu/docs/integrate/purse-reports/) (transactions, settlements, chargebacks). ## Advanced Flow & SecureFields SDKs - [Advanced Flow](https://docs.payment.purse.eu/docs/integrate/purse-api/additional-features/advanced-flow/): Full-control integration — collect card data with a SecureFields SDK, get a `vault_form_token`, then create the payment server-side. - [Web SDK](https://docs.payment.purse.eu/docs/integrate/purse-api/additional-features/advanced-flow/collect-card-details): Secure iframes (CDN or npm) collecting card data in the browser; includes customization, events, and [Oney private cards](https://docs.payment.purse.eu/docs/integrate/purse-api/additional-features/advanced-flow/oney-private-cards). - Native SDKs: [iOS](https://docs.payment.purse.eu/docs/integrate/purse-api/additional-features/advanced-flow/native-sdks/ios/) (UIKit/SwiftUI, Swift Package Manager) and [Android](https://docs.payment.purse.eu/docs/integrate/purse-api/additional-features/advanced-flow/native-sdks/android/) (Jetpack Compose/View system, Maven Central) collect card data on-device. - [Create a Payment](https://docs.payment.purse.eu/docs/integrate/purse-api/additional-features/advanced-flow/create-payment): Exchange a `vault_form_token` via `POST /payment/v2/payments`; see [token payments](https://docs.payment.purse.eu/docs/integrate/purse-api/additional-features/advanced-flow/token-payment) and the [complete flow](https://docs.payment.purse.eu/docs/integrate/purse-api/additional-features/advanced-flow/complete-payment-flow) with 3DS and redirects. - [Alternative Payment Methods](https://docs.payment.purse.eu/docs/integrate/purse-api/additional-features/advanced-flow/apm-payments): PayPal and Apple Pay — integrate with the PSP directly, then pass `split[].paypal.order_id`, `split[].paypal.setup_token_id` or `split[].applepay.token` to `POST /payment/v2/payments`. ## Checkout Integration Modes - [Drop-in Checkout](https://docs.payment.purse.eu/docs/integrate/purse-checkout/drop-in/): Pre-built, fully-featured widget with minimal integration effort — theming, localization, events, hooks, error handling, API reference. - [Headless Checkout SDK](https://docs.payment.purse.eu/docs/integrate/purse-checkout/headless-checkout/): Full control over the checkout flow; highest effort, all payment methods. Includes an [error model and code catalogue](https://docs.payment.purse.eu/docs/integrate/purse-checkout/headless-checkout/error-handling/). - [Headless Advanced Guides](https://docs.payment.purse.eu/docs/integrate/purse-checkout/headless-checkout/advanced-guides/): Amounts, ANCV, gift cards, installments, digital wallets, saved methods, sessions, redirect, events, hooks, performance — plus [Hosted Fields](https://docs.payment.purse.eu/docs/integrate/purse-checkout/headless-checkout/advanced-guides/hosted-fields) (`getHostedFields()`) and [Hosted Form](https://docs.payment.purse.eu/docs/integrate/purse-checkout/headless-checkout/advanced-guides/hosted-form) (`getPaymentElement()` with `hostedForm`). - [Hosted Page](https://docs.payment.purse.eu/docs/integrate/purse-checkout/hosted-page/): Payment interface served by Purse. Lowest effort, limited customization, all methods including pay-by-link and MOTO. - [Checkout Showcase](https://docs.payment.purse.eu/docs/checkout-showcase/): Live, runnable Headless Checkout examples. [Widget V3](https://docs.payment.purse.eu/docs/integrate/purse-checkout/widget-v3/) is deprecated but documented, with migration guides. ## API Reference - [Payment API v2](https://docs.payment.purse.eu/openapi/payment-api-v2): Primary OpenAPI specification — all endpoints, schemas, authentication. [v1](https://docs.payment.purse.eu/openapi/payment-api-v1) is deprecated. - [Wallet API v3](https://docs.payment.purse.eu/openapi/wallet-api-v3): Stored payment methods and tokenized cards ([v2](https://docs.payment.purse.eu/openapi/wallet-api-v2) still published). - [Vault API v1](https://docs.payment.purse.eu/openapi/vault-api-v1): Card vaulting endpoints used by the SecureFields SDKs. - [XCO API v1](https://docs.payment.purse.eu/openapi/xco-api-v1): Merchant user, passwordless authentication, and consent challenge endpoints. ## Concepts, Reference & Partners - [Payment Concepts](https://docs.payment.purse.eu/docs/understand/payment-concepts): Authorization, capture, refund, void, and the payment lifecycle; [use cases](https://docs.payment.purse.eu/docs/understand/use-cases) map common scenarios to implementations. - [Glossary](https://docs.payment.purse.eu/docs/references/glossary/payment): Payment, [client session](https://docs.payment.purse.eu/docs/references/glossary/client-session), [entity](https://docs.payment.purse.eu/docs/references/glossary/entity), [payment flows](https://docs.payment.purse.eu/docs/references/glossary/payment-flows/) (one/two/three-step), 3DS, idempotency, PCI-DSS, redirection. - [Convention Guide](https://docs.payment.purse.eu/docs/references/convention): API naming conventions, data formats, standards. [SDK CDN URLs](https://docs.payment.purse.eu/docs/references/sdk-cdn-urls) lists script links. - [Payment Partners](https://docs.payment.purse.eu/docs/partners): 100+ supported payment service providers and methods, with per-partner integration guides.