### Normal **FastAPI**

First, write all your **FastAPI** application as normally:

{* ../../docs_src/extending_openapi/tutorial001.py hl[1,4,7:9] *}

### Generate the OpenAPI schema

# Form Data

When you need to receive form fields instead of JSON, you can use `Form`.

/// info

To use forms, first install <a href="https://github.com/Kludex/python-multipart" class="external-link" target="_blank">`python-multipart`</a>.

Make sure you create a [virtual environment](../virtual-environments.md){.internal-link target=_blank}, activate it, and then install it, for example:

```console
$ pip install python-multipart
```

///

   * checkNotNull
   *
   * @param predicateType The first parameter to the method (boolean or Object)
   */
  private static ImmutableList<ImmutableList<Class<?>>> allSignatures(Class<?> predicateType) {
    ImmutableSet.Builder<ImmutableList<Class<?>>> allOverloads = ImmutableSet.builder();
    // The first two are for the overloads that don't take formatting args, e.g.

   *
   * @param bytes the input buffer
   * @param off the offset in the buffer of the first byte to read
   * @param len the number of bytes to read from the buffer
   */
  public static boolean isWellFormed(byte[] bytes, int off, int len) {
    int end = off + len;
    checkPositionIndexes(off, end, bytes.length);
    // Look for the first non-ASCII character.
    for (int i = off; i < end; i++) {
      if (bytes[i] < 0) {

@ReflectionSupport(value = ReflectionSupport.Level.FULL)
@ElementTypesAreNonnullByDefault
abstract class AggregateFutureState<OutputT extends @Nullable Object>
    extends AbstractFuture.TrustedFuture<OutputT> {
  // Lazily initialized the first time we see an exception; not released until all the input futures
  // have completed and we have processed them all.
  @CheckForNull private volatile Set<Throwable> seenExceptions = null;

  private volatile int remaining;

        printErrors(result);

        Iterator<Artifact> i = result.getArtifacts().iterator();
        assertEquals(n, i.next(), "n should be first");
        assertEquals(m, i.next(), "m should be second");

        // inverse order
        set = new LinkedHashSet<>();
        set.add(m);
        set.add(n);

     * specified through this <tt>jcifs.properties</tt> system property.
     * 
     * @return a global context, initialized on first call
     */
    public static synchronized final SingletonContext getInstance () {
        if ( INSTANCE == null ) {
            try {
                log.debug("Initializing singleton context");

Because **FastAPI** doesn't make any changes to a `Response` you return, you have to make sure its contents are ready for it.

For example, you cannot put a Pydantic model in a `JSONResponse` without first converting it to a `dict` with all the data types (like `datetime`, `UUID`, etc) converted to JSON-compatible types.

For those cases, you can use the `jsonable_encoder` to convert your data before passing it to a response:

   * provided for consistency with the other primitive types, whose compare methods were not added
   * to the JDK until JDK 7.
   *
   * @param a the first {@code float} to compare
   * @param b the second {@code float} to compare
   * @return the result of invoking {@link Float#compare(float, float)}
   */
  @InlineMe(replacement = "Float.compare(a, b)")

   * provided for consistency with the other primitive types, whose compare methods were not added
   * to the JDK until JDK 7.
   *
   * @param a the first {@code double} to compare
   * @param b the second {@code double} to compare
   * @return a negative value if {@code a} is less than {@code b}; a positive value if {@code a} is