You can change the privacy of the bin from and to Private and Public access.

Root
https://api.jsonbin.io/v3
Route
/b/<BIN_ID>/meta/privacy
Request Type
PUT
Request Headers
Header Value Required
X-Master-Key <YOUR_API_KEY> Yes
X-Bin-Private true/false Yes
X-Master-Key

X-Master-Key needs to be passed in-order to Update a Bins privacy. In-order to get the key, you need to sign-up and navigate to API Keys page.

X-Bin-Private

You can change a bin's privacy by passing true or false value. If you pass false, the bin will be Public.

Basic Code Samples
curl -v\
  -H "X-Master-key: <YOUR_API_KEY>" \
  -H "X-Bin-Private: true" \
  --request PUT \
  --data '{}' \
    https://api.jsonbin.io/v3/b/<BIN_ID>/meta/privacy
let req = new XMLHttpRequest();

req.onreadystatechange = () => {
  if (req.readyState == XMLHttpRequest.DONE) {
    console.log(req.responseText);
  }
};

req.open("PUT", "https://api.jsonbin.io/v3/b/<BIN_ID>/meta/privacy", true);
req.setRequestHeader("X-Bin-Private", "true");
req.setRequestHeader("X-Master-Key", "<YOUR_API_KEY>");
req.send();
import requests
url = 'https://api.jsonbin.io/v3/b/<BIN_ID>/meta/privacy'
headers = {
  'X-Bin-Private': 'true',
  'X-Master-Key': '<YOUR_API_KEY>'
}
data = {}

req = requests.put(url, json=data, headers=headers)
print(req.text)
require 'net/http'
require 'json'

uri = URI("https://api.jsonbin.io/v3/b/<BIN_ID>/meta/privacy")
res = Net::HTTP.start(uri.host, uri.port, use_ssl: true) do |http|
  req = Net::HTTP::Put.new(uri)
  req['X-Bin-Private'] = 'true'
  req['X-Master-Key'] = '<YOUR_API_KEY>'

  req.body = {}.to_json
  http.request(req)
end

puts res.body
Request Response
Success
200
{
    "record": "RECORD_ID",
    "metadata": {
        "private": true
    }
}
Error
400, 401, 403, 404
{
  "message": "<ERROR_MESSAGE>"
}
Status Code Error Message
400 Bad Request
You need to provide X-Bin-Private header to change the Bin privacy
400 Bad Request
Invalid Bin Id provided
404 Not Found
Bin not found
401 Unauthorized
You need to pass X-Master-Key in the header to update a private bin
401 Unauthorized
Invalid X-Master-Key provided or the bin does not belong to your account
403 Forbidden
Requests exhausted. Buy additional requests at https://jsonbin.io/pricing