PHP

create request php-salesforce-rest-api

    $data = [
       'Name' => 'Some name',
    ];

    /* returns the id of the created object */
    $salesforceFunctions->create('Account', $data);

update request php-salesforce-rest-api

    $new_data = [
       'Name' => 'another name',
    ];

    /* returns statuscode */
    $salesforceFunctions->update('Account', $id, $new_data);

upsert request php-salesforce-rest-api

    $new_data = [
       'Name' => 'another name',
    ];

    /* returns statuscode */
    $salesforceFunctions->upsert('Account', 'API Name/ Field Name', 'value', $new_data);