Careerjet

Important notes:

the GET parameters <USER_IP> and <USER_AGENT> are required and must be replaced by actual values.
the header field Referer is required and contains the page from which the API call was initially triggered. For example, if your page is https://example-publisher-site.com/find-jobs/, then the Referer field should contain exactly that.
the fields search and location are optional but are limited to your country

Example code

const API_HOSTNAME = 'search.api.careerjet.net';
const API_SEARCH_PATH = '/v4/query';
const API_KEY = '<API_KEY>';
const REFERER = 'https://example-publisher-site.com/find-jobs/?s=python+developer&l=London';

const PARAMS = {
  locale_code: 'en_IM',
  keywords: 'javascript developer',
  location: 'London',
  user_ip: '<USER_IP>',
  user_agent: '<USER_AGENT>',
};
const query = new URLSearchParams(PARAMS).toString();

const headers = new Headers();
headers.set('Authorization', `Basic ${btoa(`${API_KEY}:`)}`);
headers.set('Content-Type', 'application/json');
headers.set('Referer', REFERER);

fetch(
  `https://${API_HOSTNAME}${API_SEARCH_PATH}?${query}`,
  {
    method: 'GET',
    headers,
  },
).then((response) => {
  if (!response.ok) {
    throw new Error(`HTTP error ${response.status}`);
  }
  return response.json();
})
.then((data) => {
  console.log(data);
})
.catch((err) => {
  console.error('Fetch failed:', err);
});