> ## Documentation Index
> Fetch the complete documentation index at: https://developers.authlete.com/llms.txt
> Use this file to discover all available pages before exploring further.

# FAPI 2.0

> Explanation about FAPI 2.0 and how Authlete supports the specification.

<Note>
  This page is for **Authlete 3.x**. For **Authlete 2.x** documentation, see [Financial-grade API (FAPI) Basics](/v2/protocols-and-flows/compliance-profiles/fapi).
</Note>

## Overview

FAPI 2.0 is a set of specifications designed to enhance the security and interoperability of APIs, primarily in the financial services and banking sectors. It represents a significant evolution from FAPI 1.0, introducing advanced security measures and refined standards to meet the growing challenges across a range of industries.

## FAPI 2.0 Security Profile

[FAPI 2.0 Security Profile (Final)](https://openid.net/specs/fapi-security-profile-2_0-final.html) is an API security profile that builds upon OAuth 2.0, with a focus on providing robust security measures for APIs across various industries. For guidance on supporting FAPI 2.0 Security Profile with Authlete, see the following article:

* [Supporting FAPI 2.0 Security Profile with Authlete](/protocols-and-flows/compliance-profiles/authorization-code-flow-in-fapi-2-0-security-profile)

## FAPI 2.0 Message Signing Profile

[FAPI 2.0 Message Signing Profile](https://openid.bitbucket.io/fapi/fapi-2_0-message-signing.html) (hereinafter referred to as FAPI2 MS) is a subset of FAPI 2.0 that extends FAPI 2.0 Security Profile as its foundation and deals with message signing. FAPI2 MS Profile primarily defines four categories of requirements:

1. [Signing Authorization Requests](https://openid.net/specs/fapi-message-signing-2_0-final.html#name-signing-authorization-reque)
2. [Signing Authorization Responses](https://openid.net/specs/fapi-message-signing-2_0-final.html#name-signing-authorization-respo)
3. [Signing Introspection Responses](https://openid.net/specs/fapi-message-signing-2_0-final.html#name-signing-introspection-respo)
4. [Signing ID Tokens](https://openid.net/specs/fapi-message-signing-2_0-final.html#name-signing-id-tokens)

For more details, please refer to the following articles:

* [Supporting FAPI2 Message Signing Profile: Signing Authorization Requests with Authlete](/protocols-and-flows/compliance-profiles/fapi-2-0-message-signing-profile-signing-authorization-requests)
* [Supporting FAPI2 Message Signing Profile: Signing Authorization Responses with Authlete](/protocols-and-flows/compliance-profiles/fapi-2-0-message-signing-profile-signing-authorization-requests)