# RPG API Express (RXS) Documentation

RPG API Express (formerly RPG-XML Suite) is a developer toolkit that allows RPG developers to work with XML or JSON, offer web services/web APIs on the IBM i, and consume web services/web APIs.

The current release of RPG API Express is version 3.5.3.

Not a customer yet? We'd love to hear about your needs to see if we can meet them. Contact us at [isupport@katointegrations.com](mailto:isupport@katointegrations.com) or visit [katointegrations.com](https://katointegrations.com/solutions/rpg-api-express/).

## RXS Version-Specific Documentation

To determine which version of documentation to refer to, please run the following command, changing the library name as needed:

```cl
CALL RXS/VERRXSBASE
```

Note: Some versions of RPG API Express (formerly RPG-XML Suite) starting with version 3.0 may report multiple versions in the output. This is for backwards-compatibility reasons. The version starting with "3" will pertain to the RXS3 API version, while the version starting with "2" will pertain to the RXS2 API version.

- [RXS 3.5.x](https://isupport.katointegrations.com/llms/rpg-api-express-3.5.md)
- [RXS 3.4.x](https://isupport.katointegrations.com/llms/rpg-api-express-3.4.md)
- [RXS 3.3x](https://isupport.katointegrations.com/llms/rpg-api-express-3.3.md)
- [RXS 3.2x](https://isupport.katointegrations.com/llms/rpg-api-express-3.2.md)
- [RXS 3.1x](https://isupport.katointegrations.com/llms/rpg-api-express-3.1.md)
- [RXS 3.0x](https://isupport.katointegrations.com/llms/rpg-api-express-3.0.md)
- [RXS 2.0x-2.8x](https://isupport.katointegrations.com/llms/rpg-api-express-2.x.md)
- [RXS 1.x](https://isupport.katointegrations.com/rxs/1.x/)

## RPG API Express Information

- [Transferring a License](https://isupport.katointegrations.com/rxs/license_transfer.md)
- [Changelog](https://isupport.katointegrations.com/rxs/changelog.md)
- [Major Differences In RXS 3.x+](https://isupport.katointegrations.com/rxs/major_differences_in_rxs3.md)
- [Replication Instructions](https://isupport.katointegrations.com/rxs/replication_instructions.md)

## Learning about XML & Web Services

- [Introduction to RXS](https://isupport.katointegrations.com/rxs/intro_to_rxs.md)
- [Introduction to XML and XSD](https://isupport.katointegrations.com/rxs/intro_to_xml_and_xsd.md)
- [XML Attributes vs. Elements](https://isupport.katointegrations.com/rxs/xml_attributes_vs_elements.md)
- [XML Document Type Definition (DTD) vs. XML Schema (XSD)](https://isupport.katointegrations.com/rxs/xml_dtd_vs_xsd.md)
- [Introduction to XPath](https://isupport.katointegrations.com/rxs/intro_to_xpath.md)
- [Working with IFS Stream Files from Green Screen (5250)](https://isupport.katointegrations.com/rxs/ifs_stream_files_from_green_screen.md)
- [Debugging Web Services](https://isupport.katointegrations.com/rxs/debug_web_services/)

## Working with SSL & IBM Digital Certificate Manager

- [Setting Up the SSL \*SYSTEM Store on IBM i](https://isupport.katointegrations.com/rxs/setting_up_ssl.md)
- [Configuring SSL Permissions](https://isupport.katointegrations.com/rxs/configuring_ssl_permissions.md)
- [Installing Certificate Authorities](https://isupport.katointegrations.com/rxs/installing_certificate_authorities.md)
- [Create a Certificate Signing Request](https://isupport.katointegrations.com/rxs/create_certificate_signing_request.md)
- [Offering SSL Web Services](https://isupport.katointegrations.com/rxs/offering_ssl_web_services.md)
- [Checking Certificate Expiration](https://isupport.katointegrations.com/rxs/checking_certificate_expiration.md)
- [Configure TLS Versions and Ciphers with Client SSL Applications](https://isupport.katointegrations.com/rxs/configure_tls_with_client_ssl_application.md)
- [Changing the \*SYSTEM Store Password](https://isupport.katointegrations.com/rxs/changing_dcm_system_store_password.md)