# ESP

This guide helps you integrate ESP into your application to authenticate users via SPID, CIE, and EIDAS.

## What is ESP?

ESP is a Service Provider implementation built on the [spid-aspnetcore](https://github.com/italia/spid-aspnetcore) library.
It enables your application to authenticate with:

* [SPID](https://www.spid.gov.it/en/) — the Italian Public Digital Identity System
* [CIE](https://www.cartaidentita.interno.gov.it/) — the Electronic Identity Card certified by the Italian State
* [EIDAS](https://eid.gov.it/home) — the Italian eIDAS login portal *(available for public administration only)*


## Documentation structure

### Get started

- [Overview](/products/esp/enterprise-documentation/get-started/get-started): onboarding process and environment setup to become a SPID/CIE Service Provider.


### Developer documentation

- **Integration Guide**: step-by-step API reference for the authentication flow:
  - [Authentication flow](/products/esp/enterprise-documentation/developer-documentation/integration-guide/authentication-flow): end-to-end guide to integrate the authentication flow
  - [Get Key](/products/esp/enterprise-documentation/developer-documentation/integration-guide/getkey)
  - [Login](/products/esp/enterprise-documentation/developer-documentation/integration-guide/login)
  - [Get user token](/products/esp/enterprise-documentation/developer-documentation/integration-guide/token)
  - [Logout](/products/esp/enterprise-documentation/developer-documentation/integration-guide/logout)


### Release Notes

Version history and changelog of ESP updates.