FTP

Mock 125 Data Connection Open Response

The data connection is already open and the transfer is beginning. No need to open a new data connection.

1 HTTP Response

HTTP Response

HTTP/1.1 125 Data Connection Open
Content-Type: application/json
Date: Tue, 25 Feb 2026 12:00:00 GMT

2 Test with curl

terminal

curl -i https://httpbin.org/status/125

3 Return 125 Data Connection Open in Your Framework

django

from django.http import HttpResponse


def my_view(request):
    return HttpResponse(status=125)  # Data Connection Open

flask

from flask import Flask

app = Flask(__name__)


@app.route("/endpoint")
def my_endpoint():
    return "", 125  # Data Connection Open

fastapi

from fastapi import FastAPI
from fastapi.responses import Response

app = FastAPI()


@app.get("/endpoint")
def my_endpoint():
    return Response(status_code=125)  # Data Connection Open

express.js

// Express.js
app.get('/endpoint', (req, res) => {
  res.sendStatus(125); // Data Connection Open
});

spring boot

import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.*;

@RestController
public class MyController {

    @GetMapping("/endpoint")
    public ResponseEntity<Void> myEndpoint() {
        return ResponseEntity
            .status(125) // Data Connection Open
            .build();
    }
}

go net/http

package main

import "net/http"

func myHandler(w http.ResponseWriter, r *http.Request) {
    w.WriteHeader(125) // Data Connection Open
}

ruby on rails

class MyController < ApplicationController
  def my_action
    head :data_connection_open
  end
end

asp.net core

// ASP.NET Core Minimal API
app.MapGet("/endpoint", () =>
    Results.StatusCode(125) // Data Connection Open
);

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