Is my app link broken?

curl -X POST https://strait.link/v1/tools/link-check \
  -H "Content-Type: application/json" \
  -d '{
    "url": "https://hilltop.page.link/summer"
  }'

const res = await fetch('https://strait.link/v1/tools/link-check', {
  method: 'POST',
  headers: { 'Content-Type': 'application/json' },
  body: JSON.stringify({
    "url": "https://hilltop.page.link/summer"
  }),
});
const data = await res.json();
console.log(res.status, data);

import requests

res = requests.post(
    "https://strait.link/v1/tools/link-check",
    json={
        "url": "https://hilltop.page.link/summer",
    },
)
print(res.status_code, res.json())

<?php
// Plain PHP with ext-curl, no packages. In Laravel, Http::post($url, $body) sends the same request.
$ch = curl_init('https://strait.link/v1/tools/link-check');
curl_setopt_array($ch, [
    CURLOPT_CUSTOMREQUEST => 'POST',
    CURLOPT_RETURNTRANSFER => true,
    CURLOPT_HTTPHEADER => [
        'Content-Type: application/json',
    ],
    CURLOPT_POSTFIELDS => json_encode([
        'url' => 'https://hilltop.page.link/summer',
    ], JSON_THROW_ON_ERROR),
]);
$response = curl_exec($ch);
if ($response === false) {
    throw new RuntimeException(curl_error($ch));
}
$status = curl_getinfo($ch, CURLINFO_RESPONSE_CODE);

echo $status, PHP_EOL;
print_r(json_decode($response, true));

import java.net.URI;
import java.net.http.HttpClient;
import java.net.http.HttpRequest;
import java.net.http.HttpResponse;

// Java 17+, java.net.http only (no dependencies).
public class Main {
    public static void main(String[] args) throws Exception {
        String body = """
            {
              "url": "https://hilltop.page.link/summer"
            }
            """;
        HttpRequest request = HttpRequest.newBuilder(URI.create("https://strait.link/v1/tools/link-check"))
            .header("Content-Type", "application/json")
            .POST(HttpRequest.BodyPublishers.ofString(body))
            .build();
        HttpResponse<String> res = HttpClient.newHttpClient().send(request, HttpResponse.BodyHandlers.ofString());
        System.out.println(res.statusCode() + " " + res.body());
    }
}

package main

import (
	"fmt"
	"io"
	"log"
	"net/http"
	"strings"
)

func main() {
	body := strings.NewReader(`{
	  "url": "https://hilltop.page.link/summer"
	}`)
	req, err := http.NewRequest(http.MethodPost, "https://strait.link/v1/tools/link-check", body)
	if err != nil {
		log.Fatal(err)
	}
	req.Header.Set("Content-Type", "application/json")
	res, err := http.DefaultClient.Do(req)
	if err != nil {
		log.Fatal(err)
	}
	defer res.Body.Close()
	data, err := io.ReadAll(res.Body)
	if err != nil {
		log.Fatal(err)
	}
	fmt.Println(res.StatusCode, string(data))
}