Converting Salesforce Short IDs to Long IDs for Integrations

If you've ever integrated Salesforce with SSO or user provisioning tools like Azure AD, you've likely run into a common issue: Salesforce record IDs in the UI are 15 characters, but your API or integration often requires the 18-character version.

To make this easier, I wrote a small PHP snippet some years ago that converts 15-character Salesforce IDs into the 18-character version, which is safe to use in integrations.

<?php
if (isset($_GET['id']) && $_GET['id'] != null) {
    header("Content-Type: application/json");
    print_r(json_encode(array(
        "id"=> to18char($_GET['id'])
    )));
}

function to18char(string $inputId) {
    $suffix = '';
    for ($i = 0; $i < 3; $i++) {
        $flags = 0;
        for ($j = 0; $j < 5; $j++) {
            $start = $i * 5 + $j;
            $end = ($i * 5 + $j + 1) - $start;
            $c = substr($inputId, $start, $end);
            if (ctype_upper($c) && $c >= 'A' && $c <= 'Z') {
                $flags = $flags + (1 << $j);
            }
        }
        if ($flags <= 25) {
            $suffix .= substr('ABCDEFGHIJKLMNOPQRSTUVWXYZ', $flags, 1);
        } else {
            $suffix .= substr('012345', $flags - 26, 1);
        }
    }
    return $inputId . $suffix;
}
?>

Usage

1. Save the script as a PHP file (e.g., sf_id.php).
2. Call it via your browser or API request with a 15-character Salesforce ID:

curl https://yourdomain.com/sf_id.php?id=0013j00000abcdE

The script will return the 18-character ID in JSON format:

{
  "id": "0013j00000abcdEFA"
}

This little script saved me a lot of time when working with Azure AD SSO and user provisioning for Salesforce, and it's a quick helper for anyone working with Salesforce API integrations.