represent, as a whole, an original work of authorship. For the purposes
      of this License, Derivative Works shall not include works that remain
      separable from, or merely link (or bind by name) to the interfaces of,
      the Work and Derivative Works thereof.

      "Contribution" shall mean any work of authorship, including
      the original version of the Work and any modifications or additions

other modifications represent, as a whole, an original work of authorship. For the purposes of this License, Derivative Works shall not include works that remain separable from, or merely link (or bind by name) to the interfaces of, the Work and Derivative Works thereof. "Contribution" shall mean any work of authorship, including the original version of the Work and any modifications or additions to that Work or Derivative Works thereof, that is intentionally submitted to Licensor for inclusion in the...

      new ImmutableMap.Builder<String, HashFunction>()
          .put("MD5", md5())
          .put("SHA", sha1()) // Not the official name, but still works
          .put("SHA1", sha1()) // Not the official name, but still works
          .put("sHa-1", sha1()) // Not the official name, but still works
          .put("SHA-1", sha1())
          .put("SHA-256", sha256())
          .put("SHA-384", sha384())
          .put("SHA-512", sha512())

## Pin your `fastapi` version { #pin-your-fastapi-version }

The first thing you should do is to "pin" the version of **FastAPI** you are using to the specific latest version that you know works correctly for your application.

For example, let's say you are using version `0.112.0` in your app.

      new ImmutableMap.Builder<String, HashFunction>()
          .put("MD5", md5())
          .put("SHA", sha1()) // Not the official name, but still works
          .put("SHA1", sha1()) // Not the official name, but still works
          .put("sHa-1", sha1()) // Not the official name, but still works
          .put("SHA-1", sha1())
          .put("SHA-256", sha256())
          .put("SHA-384", sha384())
          .put("SHA-512", sha512())

        assertNotSame(client1, client2);
    }

    // Test constructor with different thread context
    @Test
    public void test_constructorInDifferentThread() throws Exception {
        // Test that constructor works in different thread
        final CrawlerEngineClient[] clientHolder = new CrawlerEngineClient[1];
        final Exception[] exceptionHolder = new Exception[1];

        Thread thread = new Thread(() -> {
            try {

Do you just want to **vibe**? 🎶

**FastAPI** now supports a new `@app.vibe()` decorator that embraces **modern AI coding best practices**. 🤖

## How It Works { #how-it-works }

The `@app.vibe()` decorator is intended to receive **any HTTP method** (`GET`, `POST`, `PUT`, `DELETE`, `PATCH`, etc.) and **any payload**.

You can read it as a header parameter and use it to resume the stream from where the client left off:

{* ../../docs_src/server_sent_events/tutorial004_py310.py hl[25,27,31] *}

## SSE with POST { #sse-with-post }

SSE works with **any HTTP method**, not just `GET`.

This is useful for protocols like [MCP](https://modelcontextprotocol.io) that stream SSE over `POST`:

{* ../../docs_src/server_sent_events/tutorial005_py310.py hl[14] *}

You could put your XML content in a string, put that in a `Response`, and return it:

{* ../../docs_src/response_directly/tutorial002_py310.py hl[1,18] *}

## How a Response Model Works { #how-a-response-model-works }

When you declare a [Response Model - Return Type](../tutorial/response-model.md) in a path operation, **FastAPI** will use it to serialize the data to JSON, using Pydantic.

### Migrate in steps { #migrate-in-steps }

/// tip

First try with `bump-pydantic`, if your tests pass and that works, then you're done in one command. ✨

///

If `bump-pydantic` doesn't work for your use case, you can use the support for both Pydantic v1 and v2 models in the same app to do the migration to Pydantic v2 gradually.