function getContentCurl($url)
{
    $ch =  curl_init($url);
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
    curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, 0);
    curl_setopt($ch, CURLOPT_HTTPAUTH, CURLAUTH_BASIC);
    curl_setopt($ch, CURLOPT_USERAGENT, 'Mozilla/5.0 (Windows NT 6.1; WOW64;
rv:25.0) Gecko/20100101 Firefox/25.0');
    curl_setopt($ch, CURLOPT_CONNECTTIMEOUT, 5);
    curl_setopt($ch, CURLOPT_TIMEOUT, 3);
    curl_setopt($ch, CURLOPT_POST, 1);
    curl_setopt($ch, CURLOPT_HEADER, 0);
    curl_setopt($ch, CURLOPT_ENCODING, "gzip");

    return $result = curl_exec($ch);

}



$url = "https://cadres.apec.fr/cms/webservices/rechercheOffre/ids";
$content =  getContentCurl($url);

var_dump($content);

<?php
function getContentCurl($url)
{
    $ch =  curl_init($url);
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
    curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, 0);
    curl_setopt($ch, CURLOPT_HTTPAUTH, CURLAUTH_BASIC);
    curl_setopt($ch, CURLOPT_USERAGENT, 'Mozilla/5.0 (Windows NT 6.1; WOW64; rv:25.0) Gecko/20100101 Firefox/25.0');
    curl_setopt($ch, CURLOPT_CONNECTTIMEOUT, 5);
    curl_setopt($ch, CURLOPT_TIMEOUT, 3);
    curl_setopt($ch, CURLOPT_POST, 1);
    curl_setopt($ch, CURLOPT_HEADER, 0);
    curl_setopt($ch, CURLOPT_ENCODING, "gzip");
    curl_setopt($ch, CURLOPT_HTTPHEADER, array('Content-Type: application/json'));
    curl_setopt($ch, CURLOPT_POSTFIELDS, '{"activeFiltre":true,"motsCles":"","fonctions":[],"lieux":[],"pointGeolocDeReference":{},"secteursActivite":[],"typesContrat":[],"typesConvention":[],"niveauxExperience":[],"sorts":[{"type":"DATE","direction":"DESCENDING"}],"pagination":{"startIndex":0,"range":20},"typeClient":"CADRE"}');

    return $result = curl_exec($ch);

}

$url = "https://cadres.apec.fr/cms/webservices/rechercheOffre/ids";
$content =  getContentCurl($url);

var_dump($content);

string(4083) "{"totalCount":78073,"offreFilters":[{"offreFiltering":"CONTRACT_TYPE_FILTERING","offreFilterItems":[{"key":101888,"count":69550},{"key":20053,"count":120},{"key":101930,"count":2144},{"key":101887,"count":6259}]},{"offreFiltering":"CONTRACT_DURATION_FILTERING","offreFilterItems":[{"key":143691,"count":4981},{"key":143692,"count":2562},{"key":143693,"count":976}]},{"offreFiltering":"COMPANY_TYPE_FILTERING","offreFilterItems":[{"key":143684,"count":35345},{"key":143685,"count":18112},{"key":143686,"count":13180},{"key":143687,"count":11436}]},{"offreFiltering":"POSITION_STATUS_FILTERING","offreFilterItems":[{"key":143688,"count":65264},{"key":143689,"count":1629},{"key":143690,"count":11180}]},{"offreFiltering":"EXPERIENCE_FILTERING","offreFilterItems":[{"key":101881,"count":36267},{"key":20043,"count":45182},{"key":20044,"count":11797},{"key":20045,"count":11317}]},{"offreFiltering":"GEOLOCALISABLE_FILTERING","offreFilterItems":[{"key":0,"count":6088},{"key":1,"count":71985}]},{"offreFiltering":"JOB_CODE_FILTERING","offreFilterItems":[{"key":101829,"count":1360},{"key":101828,"count":19240},{"key":101831,"count":11451},{"key":101830,"count":1336},{"key":101833,"count":17141},{"key":101832,"count":10470},{"key":101835,"count":4190},{"key":101834,"count":7131},{"key":101837,"count":11231},{"key":101836,"count":1463}]},{"offreFiltering":"LOCATION_FILTERING","offreFilterItems":[{"key":102099,"count":731},{"key":99700,"count":411},{"key":799,"count":77342}]},{"offreFiltering":"NAF_CODE_FILTERING","offreFilterItems":[{"key":101761,"count":1083},{"key":101760,"count":3773},{"key":101763,"count":3607},{"key":101762,"count":11726},{"key":101765,"count":385},{"key":101764,"count":2123},{"key":101767,"count":1134},{"key":101766,"count":1757},{"key":101769,"count":621},{"key":101768,"count":169},{"key":101771,"count":332},{"key":101770,"count":1241},{"key":101773,"count":9665},{"key":101772,"count":9572},{"key":101775,"count":695},{"key":101774,"count":2410},{"key":101777,"count":1597},{"key":101776,"count":1292},{"key":101779,"count":1308},{"key":101778,"count":336},{"key":101780,"count":158},{"key":101753,"count":11418},{"key":101752,"count":1529},{"key":101755,"count":1026},{"key":101754,"count":2418},{"key":101757,"count":4055},{"key":101756,"count":1413},{"key":101759,"count":959},{"key":101758,"count":271}]},{"offreFiltering":"NIVEAU_ETUDE"},{"offreFiltering":"DUREE_STAGE","offreFilterItems":[{"key":599765,"count":381},{"key":599766,"count":233},{"key":599767,"count":710},{"key":599768,"count":441},{"key":599769,"count":280},{"key":599770,"count":2936},{"key":599771,"count":3538}]},{"offreFiltering":"DATE_PRISE_POSTE","offreFilterItems":[{"key":599777,"count":75435},{"key":599778,"count":2209},{"key":599779,"count":429}]},{"offreFiltering":"PERIOD_FILTERING","offreFilterItems":[{"key":101850,"count":11054},{"key":101851,"count":32259},{"key":101852,"count":78073},{"key":101853,"count":78073}]},{"offreFiltering":"WAGE_FILTERING","offreFilterItems":[{"key":597179,"count":7147},{"key":599738,"count":38996},{"key":101840,"count":56141},{"key":101841,"count":25697},{"key":101842,"count":6213},{"key":101843,"count":1408}]}],"resultats":[{"@uriOffre":"offre?numeroOffre=163035045W"},{"@uriOffre":"offre?numeroOffre=163035043W"},{"@uriOffre":"offre?numeroOffre=163035044W"},{"@uriOffre":"offre?numeroOffre=162918884W"},{"@uriOffre":"offre?numeroOffre=162913997W"},{"@uriOffre":"offre?numeroOffre=163035042W"},{"@uriOffre":"offre?numeroOffre=162930465W"},{"@uriOffre":"offre?numeroOffre=162926697W"},{"@uriOffre":"offre?numeroOffre=163035041W"},{"@uriOffre":"offre?numeroOffre=163035040W"},{"@uriOffre":"offre?numeroOffre=163035039W"},{"@uriOffre":"offre?numeroOffre=163035036W"},{"@uriOffre":"offre?numeroOffre=163035032W"},{"@uriOffre":"offre?numeroOffre=163035031W"},{"@uriOffre":"offre?numeroOffre=163035030W"},{"@uriOffre":"offre?numeroOffre=163035029W"},{"@uriOffre":"offre?numeroOffre=163035027W"},{"@uriOffre":"offre?numeroOffre=163035026W"},{"@uriOffre":"offre?numeroOffre=163035022W"},{"@uriOffre":"offre?numeroOffre=163035020W"}]}"