# API: Functionality and Documentation

- [Authentication with Personal Access Token](/integrations-and-connections/api-functionality-and-documentation/authentication-with-personal-access-token.md): How to authenticate with the sipgate REST API using personal access tokens, including scope management and security benefits.
- [What Is the sipgate API and what features does it offer?](/integrations-and-connections/api-functionality-and-documentation/what-is-the-sipgate-api-and-what-features-does-it-offer.md): Overview of the sipgate API features including call building, SMS, fax, voicemail access, and event list retrieval.
- [How can I use the sipgate API?](/integrations-and-connections/api-functionality-and-documentation/how-can-i-use-the-sipgate-api.md): How to communicate with the sipgate API via XML-RPC, authenticate with OAuth 2.0 or Personal Access Token, and usage costs.
- [sipgate API Technical Specification](/integrations-and-connections/api-functionality-and-documentation/sipgate-api-technical-specification.md): Download link for the detailed sipgate API technical specification PDF document.
- [What changes will the new system bring to the sipgate REST API and sipgate.io?](/integrations-and-connections/api-functionality-and-documentation/what-changes-will-the-new-system-bring-to-the-sipgate-rest-api-and-sipgateio.md): Changes to the sipgate REST API and sipgate.io with the new sipgate neo system, including history, push API, RTCM, and channels.