I build secure, scalable, and high-performance web applications using modern standards. I specialise in PHP, MySQL, JavaScript, and advanced table-driven interfaces like DataTables.
Core skills
Short bio
Xavid Ahmed (X4V1D) is a Bangladeshi web developer focused on building clean, maintainable code and delightful user experiences. Available for freelance and contract work.
Featured Projects
Customer Management System
Custom CRUD application with modal editing, CSV export, and user management with role-based permissions.
Telegram WebApp Coin System
Secure webhook & WebApp integration for user onboarding, rewards and transaction management for community engagement.
Google Sheets Automation
Apps Script + PHP bridge for live spreadsheet workflows with real-time synchronization and data visualization.
Code Examples
Here are some code snippets showcasing my coding style and expertise:
/**
* Secure AES-256 encryption/decryption helper class
*/
class Encryption {
private $key;
private $cipher = 'aes-256-cbc';
public function __construct($key) {
$this->key = hash('sha256', $key, true);
}
public function encrypt($data) {
$ivSize = openssl_cipher_iv_length($this->cipher);
$iv = openssl_random_pseudo_bytes($ivSize);
$encrypted = openssl_encrypt(
$data,
$this->cipher,
$this->key,
OPENSSL_RAW_DATA,
$iv
);
// Return IV + encrypted data in base64
return base64_encode($iv . $encrypted);
}
public function decrypt($data) {
$data = base64_decode($data);
$ivSize = openssl_cipher_iv_length($this->cipher);
$iv = substr($data, 0, $ivSize);
$encrypted = substr($data, $ivSize);
return openssl_decrypt(
$encrypted,
$this->cipher,
$this->key,
OPENSSL_RAW_DATA,
$iv
);
}
}/**
* DataTables enhanced initialization with AJAX support
*/
class DataTableManager {
constructor(tableId, options = {}) {
this.tableId = tableId;
this.options = {
processing: true,
serverSide: true,
responsive: true,
...options
};
this.table = null;
this.init();
}
init() {
this.table = $(`#${this.tableId}`).DataTable(this.options);
this.attachEventHandlers();
return this;
}
attachEventHandlers() {
// Handle row selection
$(`#${this.tableId} tbody`).on('click', 'tr', (e) => {
const $row = $(e.currentTarget);
$row.toggleClass('selected');
// Trigger custom event
const rowData = this.table.row($row).data();
$(document).trigger('dt:rowSelect', [rowData, $row.hasClass('selected')]);
});
// Handle refresh
$(document).on('dt:refresh', () => this.refresh());
return this;
}
refresh() {
this.table.ajax.reload();
return this;
}
getData() {
return this.table.rows().data().toArray();
}
getSelectedRows() {
return this.table.rows('.selected').data().toArray();
}
}-- Advanced query for reporting with multiple joins
SELECT
u.id AS user_id,
CONCAT(u.first_name, ' ', u.last_name) AS user_name,
COUNT(DISTINCT o.id) AS total_orders,
SUM(oi.quantity * p.price) AS total_spent,
AVG(oi.quantity * p.price) AS avg_order_value,
MAX(o.created_at) AS last_order_date,
GROUP_CONCAT(DISTINCT c.name ORDER BY c.name SEPARATOR ', ') AS categories_purchased
FROM
users u
LEFT JOIN
orders o ON u.id = o.user_id
LEFT JOIN
order_items oi ON o.id = oi.order_id
LEFT JOIN
products p ON oi.product_id = p.id
LEFT JOIN
product_categories pc ON p.id = pc.product_id
LEFT JOIN
categories c ON pc.category_id = c.id
WHERE
u.status = 'active'
AND o.created_at >= DATE_SUB(NOW(), INTERVAL 6 MONTH)
GROUP BY
u.id
HAVING
total_orders > 0
ORDER BY
total_spent DESC
LIMIT 100;