It just extends OAuth2 specifying some things that are relatively ambiguous in OAuth2, to try to make it more interoperable.

For example, Google login uses OpenID Connect (which underneath uses OAuth2).

But Facebook login doesn't support OpenID Connect. It has its own flavor of OAuth2.

### OpenID (not "OpenID Connect")

There was also an "OpenID" specification. That tried to solve the same thing as **OpenID Connect**, but was not based on OAuth2.

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"_If you're looking to learn one **modern framework** for building REST APIs, check out **FastAPI** [...] It's fast, easy to use and easy to learn [...]_"

"_We've switched over to **FastAPI** for our **APIs** [...] I think you'll like it [...]_"

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"_If you're looking to learn one **modern framework** for building REST APIs, check out **FastAPI** [...] It's fast, easy to use and easy to learn [...]_"

"_We've switched over to **FastAPI** for our **APIs** [...] I think you'll like it [...]_"

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"_If you're looking to learn one **modern framework** for building REST APIs, check out **FastAPI** [...] It's fast, easy to use and easy to learn [...]_"

"_We've switched over to **FastAPI** for our **APIs** [...] I think you'll like it [...]_"

## What is "Dependency Injection"

**"Dependency Injection"** means, in programming, that there is a way for your code (in this case, your *path operation functions*) to declare things that it requires to work and use: "dependencies".

And then, that system (in this case **FastAPI**) will take care of doing whatever is needed to provide your code with those needed dependencies ("inject" the dependencies).

* Chuyển đổi tự động các JSON object đến và JSON object đi.
* Tài liệu hóa mọi thứ với OpenAPI, tài liệu đó có thể được sử dụng bởi:

    * Các hệ thống tài liệu có thể tương tác.
    * Hệ thống sinh code tự động, cho nhiều ngôn ngữ lập trình.
* Cung cấp trực tiếp 2 giao diện web cho tài liệu tương tác

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"_If you're looking to learn one **modern framework** for building REST APIs, check out **FastAPI** [...] It's fast, easy to use and easy to learn [...]_"

"_We've switched over to **FastAPI** for our **APIs** [...] I think you'll like it [...]_"

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"_If you're looking to learn one **modern framework** for building REST APIs, check out **FastAPI** [...] It's fast, easy to use and easy to learn [...]_"

"_We've switched over to **FastAPI** for our **APIs** [...] I think you'll like it [...]_"

<div style="text-align: left; direction: ltr;">"We've switched over to <strong>FastAPI</strong> for our <strong>APIs</strong> [...] I think you'll like it [...]"</div>

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"_If you're looking to learn one **modern framework** for building REST APIs, check out **FastAPI** [...] It's fast, easy to use and easy to learn [...]_"

"_We've switched over to **FastAPI** for our **APIs** [...] I think you'll like it [...]_"