# anybill Developer Documentation > anybill is a digital receipt platform for retail merchants. This documentation > covers the Frontend SDKs (Android, iOS, Flutter, React Native, Web) that > deliver digital receipts to consumer apps, the Vendor API for point-of-sale > systems, the Partner Platform API for backend-to-backend integration, and the > webhook channels that push receipt and loyalty events. This file follows the > llmstxt.org standard and is intended as the single entry point for AI coding > agents (Cursor, Claude Code, GitHub Copilot, Codex) integrating anybill. ## Architecture and Data Flow - [Architecture and Data Flow](https://developer.anybill.de/architecture_and_data_flow/index.md): High-level overview of the anybill platform architecture, the participating systems, and how receipt data flows between merchants, customers, and third parties. ## Frontend SDKs - [Overview](https://developer.anybill.de/the_anybill_sdk/overview.md): Entry point for the Frontend SDKs, including the linked-user-account authentication flow. - [AI-Assisted Integration](https://developer.anybill.de/the_anybill_sdk/ai_assisted_integration.md): How to integrate the SDK with AI coding agents using this documentation and a ready-to-use AGENTS.md. - [Documentation and Changelog](https://developer.anybill.de/the_anybill_sdk/native_sdks.md): Versioned reference and changelog for the native Android and iOS SDKs. - [Android Integration](https://developer.anybill.de/the_anybill_sdk/android_integration.md): Step-by-step integration guide for the Kotlin Android SDK. - [iOS Integration](https://developer.anybill.de/the_anybill_sdk/ios_integration.md): Step-by-step integration guide for the Swift iOS SDK. - [Flutter Integration](https://developer.anybill.de/the_anybill_sdk/flutter_integration.md): Integration guide for the Flutter SDK wrapping the native implementations. - [React Native Integration](https://developer.anybill.de/the_anybill_sdk/react_native_integration.md): Preview integration guide for the React Native SDK. - [Web Integration](https://developer.anybill.de/the_anybill_sdk/web_integration.md): Integration guide for the TypeScript Web SDK. ## Vendor API - [Overview](https://developer.anybill.de/vendor_api/index.md): Getting-started checklist for integrating the Vendor API into a point-of-sale system, plus retry policy, Postman collection and license. - [AI-Assisted Integration](https://developer.anybill.de/vendor_api/ai_assisted_integration.md): How to integrate the Vendor API into a POS system with AI coding agents or chat assistants, using this documentation, a Vendor API llms.txt and a ready-to-use AGENTS.md. - [Environments](https://developer.anybill.de/vendor_api/environments.md): Available environments of the Vendor API and their base URLs. - [Authentication](https://developer.anybill.de/vendor_api/authentication.md): OAuth 2.0 service-account authentication flow, scopes, access and refresh tokens for the Vendor API. - [Bill Endpoints](https://developer.anybill.de/vendor_api/bill_endpoints.md): Routes for sending, cancelling and pre-registering receipts, user identification, and the required request fields. - [Bill Data Model](https://developer.anybill.de/vendor_api/bill_data_model.md): Structure of the BillDTO: head, data, security and misc, plus the value reference for lines, payment types, quantity measures and currencies. - [Fiscalization](https://developer.anybill.de/vendor_api/fiscalization.md): How to send fiscalization data in bill.security: the required and failure flags, the type discriminator, the mandatory fields per fiscalization type (TSE, RKSV, BOI-TVA, TicketBAI, Sweden, Portugal, generic) and the deprecated field names. - [Bill Examples](https://developer.anybill.de/vendor_api/bill_examples.md): Worked payload examples for discounts on line items and whole receipts, returning a line item, and custom sections. - [Print Buffer Format Guide](https://developer.anybill.de/vendor_api/print_buffer.md): Control-sequence format for transmitting a pre-rendered receipt layout as a print buffer. - [Store Endpoints](https://developer.anybill.de/vendor_api/store_endpoints.md): Creating, searching and deleting stores, and the required fields of each store request. - [Loyalty Endpoints](https://developer.anybill.de/vendor_api/loyalty_endpoints.md): Starting and cancelling loyalty transactions, linking them to receipts, and the required request fields. - [Customer and Cashier Display](https://developer.anybill.de/vendor_api/customer_display.md): Rendering the QR code on the checkout customer display. - [Integration Review](https://developer.anybill.de/vendor_api/integration_review.md): How the anybill POS Integration Team reviews a POS integration before go-live, what to prepare, and the questions the review goes through. - [E-Invoice (ZUGFeRD / XRechnung)](https://developer.anybill.de/vendor_api/e_invoice.md): How a POS marks a receipt as an e-invoice via misc.extension:anybill.receiptType = EInvoice, how it can pass customer data in a free structure via misc.extension:anybill.merchantCustomObject, how the buyer requests a ZUGFeRD PDF or XRechnung XML on the receipt page, and which receipt fields the e-invoice is built from. ## Vendor API SDK - [Overview](https://developer.anybill.de/vendor_api_sdk/overview.md): Summary of the C# Vendor API SDK, features and changelog. - [Configuration](https://developer.anybill.de/vendor_api_sdk/configuration.md): How to add anybill's private NuGet feed (JFrog Artifactory) as a package source in the dotnet CLI, nuget.exe, Visual Studio or a project NuGet.config. - [C# Integration](https://developer.anybill.de/vendor_api_sdk/csharp_integration.md): End-to-end integration example for the C# SDK. ## Partner Platform API - [Overview](https://developer.anybill.de/partner_platform_api/index.md): Introduction to the Partner Platform API and its service-account model. - [Environments](https://developer.anybill.de/partner_platform_api/environments.md): Available environments and their base URLs. - [Authentication](https://developer.anybill.de/partner_platform_api/api_authentication.md): Service-account authentication flow for the Partner Platform API. - [Partner Platform V3](https://developer.anybill.de/partner_platform_api/api_v3.md): Endpoints and use cases for the current API version, including user provisioning and SDK token creation. ## Webhooks - [Overview](https://developer.anybill.de/webhooks/overview.md): Authentication, headers, and common use cases for anybill webhooks. - [Receipt Notification](https://developer.anybill.de/webhooks/receipt_notification.md): Payload and delivery semantics for the receipt-created webhook. - [Loyalty](https://developer.anybill.de/webhooks/loyalty.md): Loyalty event webhook payload and behaviour. ## Security and Compliance - [Security and Compliance](https://developer.anybill.de/security_and_compliance/index.md): Data-centre location, encryption, access control, availability guarantees, and the legal requirements for issuing a digital receipt. ## Optional - [anybill Developer Documentation](https://developer.anybill.de/index.md): anybill is the leading digital receipt platform that enables Data Insights, Customer Loyalty and Marketing Attribution. - [Imprint](https://developer.anybill.de/imprint/index.md): Legal imprint for anybill GmbH. - [Privacy Policy](https://developer.anybill.de/privacy/index.md): Privacy policy (Datenschutzerklärung) for developer.anybill.de: hosting, consent management, usage analytics and the AI chat widget. - [Changelog](https://developer.anybill.de/changelog/index.md): Dated list of relevant changes to the anybill developer documentation: new pages, corrected API behaviour, renamed fields and new downloads. - [AGENTS.md download (Frontend SDKs)](https://developer.anybill.de/downloads/anybill-sdk-AGENTS.md): Ready-to-drop-in AGENTS.md file for AI coding agents working on an anybill Frontend SDK integration. - [AGENTS.md download (Vendor API)](https://developer.anybill.de/downloads/anybill-vendorapi-AGENTS.md): Ready-to-drop-in AGENTS.md file for AI coding agents working on a POS integration of the anybill Vendor API. - [Vendor API llms.txt](https://developer.anybill.de/downloads/anybill-vendorapi-llms.txt): Focused llms.txt index covering only the Vendor API, the C# POS SDK, webhooks and the OpenAPI specification. - [Vendor API OpenAPI specification (production)](https://vendor.anybill.de/api/swagger/v3/swagger.json): Live OpenAPI 3 document of the production Vendor API; the authoritative schema for every request and response. - [Vendor API OpenAPI specification (staging)](https://vendor.stg.anybill.de/api/swagger/v3/swagger.json): Live OpenAPI 3 document of the staging Vendor API, where new features appear first.