Multipart Parser

Component to manage processing of multipart form data according to RFC7578, mostly used to support file uploads via HTTP/POST.


While setting up your web server, register the body parser provided by the library:

#include <MultipartParser.h>

HttpServer server;

server.setBodyParser(MIME_FORM_MULTIPART, formMultipartParser);

Now add a HttpMultipartResource for the path to receive the multipart data:

void fileUploadMapper(HttpFiles& files)
    files["file"] = <writable_stream_to_process_file>;

int onUpload(HttpServerConnection& connection, HttpRequest& request, HttpResponse& response)
    // `file` points to the stream from `fileUploadMapper`.
    auto* file = request.files["file"];

    // TODO: use methods of `file` to check if data was processed successfully

    // TODO: setup HTTP response

    return 0;


server.paths.set("/upload", new HttpMultipartResource(fileUploadMapper, onUpload));

See HttpServer Firmware Upload for further details.

Upgrade Notes

The functionality provided by this lirbary was previously controlled by the config option ENABLE_HTTP_SERVER_MULTIPART.

To upgrade, you have to replace:



ARDUINO_LIBRARIES += MultipartParser

in your In addition, body parser registration must now be done explicitly by application (see above).

API Documentation


Used by

SoC support

  • esp32

  • esp32c3

  • esp32s2

  • esp32s3

  • esp8266

  • host

  • rp2040

Submodule: multipart-parser