Live Platform

Auctune — Auction & Bidding Platform

Real-Time WebSocket Bidding with Anti-Sniping Protection

Live Demo

LaravelPHPMySQLWebSocketsAuction TechRedis

Live Auctions Hosted

400+total

Concurrent Bidders

250+peak

Bid Latency

<100ms

Settlement Success

99.5%

Real-time online auction marketplace featuring auto-bidding algorithms, countdown timers, anti-sniping protection, seller listings, and payment settlement. Built to guarantee bid integrity under heavy concurrent load.

Architecture & System Design

Bid placement runs inside a locked database transaction to guarantee atomicity, with confirmed bids broadcast over WebSockets to every connected viewer. Auctions nearing close auto-extend their countdown to prevent last-second sniping.

Request Flow

Auction Listing

Bid Submission

Row-Locked Bid Validation

WebSocket Broadcast

Anti-Sniping Timer Extension

Auction Close

Payment Settlement

Pessimistic row-locking on bid placement to prevent race conditions under load
WebSocket broadcasting for instant bid updates across all connected viewers
Anti-sniping logic that auto-extends the countdown on late bids
Escrow-based payment settlement triggered on auction close

Engineering Challenges

Race Conditions on Simultaneous Bids

Problem

Multiple bidders submitting near-identical bids at the same instant risked accepting an invalid or stale bid as the winner.

Solution

Implemented database row-level locking with atomic bid validation inside a single transaction before any bid is accepted.

Result

Zero invalid concurrent bid acceptances observed under load testing with 250+ concurrent bidders.

Last-Second Bid Sniping

Problem

Bidders were winning auctions by placing bids in the final second, leaving no chance for others to respond.

Solution

Added an auto-extending countdown that pushes the auction end time out whenever a bid lands inside the closing window.

Result

Sniping-related disputes reduced to near zero.

Real-Time State Synchronization

Problem

All connected viewers needed to see the current bid state instantly and consistently, even under high concurrency.

Solution

Used server-authoritative WebSocket broadcasting so every client reconciles against the same confirmed bid state.

Result

Bid updates propagate to all viewers in under 100ms.

Core Features

Real-Time Bid Broadcasting

WebSocket-powered live bid updates visible to every connected viewer instantly.

Clean Code

BidService — Lock-Safe Bid Placement & Broadcast

1<?php
2
3namespace App\Services;
4
5use App\Models\Auction;
6use App\Events\BidPlaced;
7use Illuminate\Support\Facades\DB;
8
9class BidService
10{
11    public function placeBid(Auction $auction, int $userId, float $amount): void
12    {
13        DB::transaction(function () use ($auction, $userId, $amount) {
14            $locked = Auction::where('id', $auction->id)
15                ->lockForUpdate()
16                ->firstOrFail();
17
18            if ($amount <= $locked->current_bid) {
19                throw new \DomainException('Bid too low');
20            }
21
22            $locked->bids()->create(['user_id' => $userId, 'amount' => $amount]);
23            $locked->update(['current_bid' => $amount]);
24
25            if ($locked->ends_at->diffInSeconds(now()) <= 30) {
26                $locked->update(['ends_at' => $locked->ends_at->addSeconds(30)]);
27            }
28
29            broadcast(new BidPlaced($locked))->toOthers();
30        });
31    }
32}