# JSON Compatible Encoder { #json-compatible-encoder }

There are some cases where you might need to convert a data type (like a Pydantic model) to something compatible with JSON (like a `dict`, `list`, etc).

For example, if you need to store it in a database.

For that, **FastAPI** provides a `jsonable_encoder()` function.

## Using the `jsonable_encoder` { #using-the-jsonable-encoder }

     * Create username/password credentials with specified domain
     *
     * @param domain the authentication domain
     * @param username the username
     * @param passwordHashHex
     *            NT password hash, hex encoded
     */
    public NtlmNtHashAuthenticator(final String domain, final String username, final String passwordHashHex) {
        this(domain, username, Hex.decode(passwordHashHex));
    }

     * to the specified maximum length.
     *
     * @param text the input text to be encoded
     * @return the encoded string, truncated if necessary
     */
    public static String createSuggestTextId(final String text) {
        final String id = encoder.encodeToString(text.getBytes(CoreLibConstants.CHARSET_UTF_8));
        if (id.length() > 445) {
            return id.substring(0, ID_MAX_LENGTH);
        }
        return id;
    }

}

// parseNumeric parses the input as being encoded in either base-256 or octal.
// This function may return negative numbers.
// If parsing fails or an integer overflow occurs, err will be set.
func (p *parser) parseNumeric(b []byte) int64 {
	// Check for base-256 (binary) format first.
	// If the first bit is set, then all following bits constitute a two's
	// complement encoded number in big-endian byte order.

This is because by default, FastAPI will inspect every item inside and make sure it is serializable as JSON, using the same [JSON Compatible Encoder](../tutorial/encoder.md){.internal-link target=_blank} explained in the tutorial. This is what allows you to return **arbitrary objects**, for example database models.

// ContainsAny reports whether any of the UTF-8-encoded code points in chars are within b.
func ContainsAny(b []byte, chars string) bool {
	return IndexAny(b, chars) >= 0
}

// ContainsRune reports whether the rune is contained in the UTF-8-encoded byte slice b.
func ContainsRune(b []byte, r rune) bool {
	return IndexRune(b, r) >= 0
}

// ContainsFunc reports whether any of the UTF-8-encoded code points r within b satisfy f(r).

        final File targetDir = new File(userDir, "target");
        return new File(targetDir, "logs").getAbsolutePath();
    }

    /**
     * Encodes a URL path for filtering.
     *
     * @param path The path to encode.
     * @return The encoded path.
     */
    public String encodeUrlFilter(final String path) {
        if (filterPathEncoding == null || path == null) {
            return path;
        }

  - reference/middleware.md
  - OpenAPI:
    - reference/openapi/index.md
    - reference/openapi/docs.md
    - reference/openapi/models.md
  - reference/security/index.md
  - reference/encoders.md
  - reference/staticfiles.md
  - reference/templating.md
  - reference/testclient.md
- fastapi-people.md
- Resources:
  - resources/index.md
  - help-fastapi.md
  - contributing.md

**FastAPI** will make sure to read that data from the right place instead of JSON.

/// note | Technical Details

Data from forms is normally encoded using the "media type" `application/x-www-form-urlencoded`.

But when the form includes files, it is encoded as `multipart/form-data`. You'll read about handling files in the next chapter.

		}
	}

	if opts.WantChecksum != nil {
		if checksumType.FullObjectRequested() {
			if opts.WantChecksum.Encoded != checksum.Encoded {
				err := hash.ChecksumMismatch{
					Want: opts.WantChecksum.Encoded,
					Got:  checksum.Encoded,
				}
				return oi, err
			}
		} else {
			err := opts.WantChecksum.Matches(checksumCombined, len(parts))
			if err != nil {