# Westpay ECL Docs

Guidance for AI agents using the Westpay ECL documentation section. This file covers the EPAS Client Library / ECL area only.

Prefer these pages in this order:

## Integration Journey

- [EPAS Client Library Overview](/docs/ECL/overview): Guided integration journey for the Westpay EPAS Client Library in .NET, Java, and Swift.
- [Connection and Login](/docs/ECL/connection-and-login): How to connect an ECR to a Westpay terminal and log in with EPAS Client Library.
- [Transactions](/docs/ECL/transactions): Purchase, refund, reversal, pre-amount, administrative operations, and diagnostics for EPAS Client Library.
- [Client Callbacks](/docs/ECL/client-callbacks): Required and optional callback methods for EPAS Client Library integrations.
- [Receipts and Events](/docs/ECL/receipts-and-events): Receipt data, DCC handling, card identification, and terminal events in EPAS Client Library.

## Language Guides

- [.NET Library](/docs/ECL/dotnet): Westpay EPAS Client Library for .NET Framework applications.
- [Java Library](/docs/ECL/java): Westpay EPAS Client Library for Java ECR applications.
- [Swift Library](/docs/ECL/swift): Westpay EPAS Client Library for Swift, macOS, and iPadOS applications.
- [Libraries](/docs/ECL/libraries): Language-specific guides for the .NET, Java, and Swift EPAS Client Library wrappers.

## Reference

- [Reference](/docs/ECL/reference): Reference material for EPAS Client Library types, wrappers, and sample applications.
- [API Reference](/docs/ECL/api-reference): Curated API reference for core methods, models, enums, and support types across the EPAS Client Library wrappers.
- [Wrapper Parity Matrix](/docs/ECL/wrapper-parity-matrix): Cross-wrapper matrix of EPAS Client Library features and helper APIs for .NET, Java, and Swift.
- [.NET Function Reference](/docs/ECL/dotnet-function-reference): Method-level reference for the .NET EPAS Client Library wrapper.
- [Java Function Reference](/docs/ECL/java-function-reference): Method-level reference for the Java EPAS Client Library wrapper.
- [Swift Function Reference](/docs/ECL/swift-function-reference): Method-level reference for the Swift EPAS Client Library wrapper.
- [Enumerations](/docs/ECL/enumerations): Important EPAS Client Library enums for results, receipt interpretation, reader control, and terminal behaviour.
- [Request and Response Models](/docs/ECL/request-response-models): Lookup reference for the main EPAS Client Library request, response, and data models.
- [Callbacks and Notifications](/docs/ECL/callbacks-and-notifications): Reference overview of callback contracts and terminal notifications in the EPAS Client Library wrappers.
- [Operating Parameters](/docs/ECL/operating-parameters): Operational settings that influence transaction behaviour, logging, and runtime integration details.

## Samples and Deliveries

- [Sample Apps](/docs/ECL/sampleECR-javadoc): Partner-facing overview of the EPAS sample applications and where to obtain their source code.
- [Library Downloads](/docs/ECL/sample-app-downloads): Partner-facing download entry point for complete ECL wrapper deliveries.

## Agent Notes

- Treat `ApiResult` as a communication or wrapper result, not as payment approval.
- Use `TransactionResponse` to determine whether a payment was approved.
- Prefer `request-response-models` and `enumerations` when mapping unknown types or enum values.
- Prefer the language-specific library or function reference pages when the user asks for exact .NET, Java, or Swift method names.
- Prefer `transactions`, `client-callbacks`, and `connection-and-login` for integration walkthroughs.