Kode Company
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E-Commerce & MarketplacesC2C & B2C Online Auctions

Bid-Buddy

Multi-Category Online Auction & Bidding Marketplace

Real-time multi-category auction platform supporting timed and live virtual auction rooms, confidential proxy bidding, anti-sniping extensions, shill-bid monitoring, and a 1% post-auction buyer connection workflow.

Client
Confidential (Identity Masked)
Region
Dubai, UAE
Industry
E-Commerce / Retail / Asset Trading
Domain
C2C / B2C Digital Auction Marketplace
Fee Model
1% Buyer Connection Fee
Kode Company branding — Build. Solve. Evolve. (Bid-Buddy)

Project Overview

Bid-Buddy enables sellers in Dubai to achieve transparent market price discovery across high-value and niche categories—including vintage watches, motorcycles, cars, fine art, antiques, collectibles, electronics, and furniture—through competitive timed and live room auctions.

Engineered on event-driven Java/Spring Boot and NestJS microservices with Angular, PostgreSQL, Redis, Apache Kafka, and WebSockets, the platform handles sub-second concurrent bidding, keeps buyer proxy maximums strictly confidential, prevents last-second sniping, and monetizes via a 1% buyer connection fee before unlocking direct buyer-seller settlement.

Business Challenges

Sellers leave value on the table with fixed prices or isolated negotiations

One-to-one haggling hides competing demand across interested collectors and asset buyers.

Concurrently arriving bids and last-second sniping distort auction fairness

Without atomic state serialization and closing-window extensions, network timing decides winners arbitrarily.

High fraud and shill-bidding risk on valuable collectibles and vehicles

Unverified sellers, off-platform contact leakage, and lack of bid-audit telemetry erode marketplace trust.

Solution & Engineering Approach

Combines atomic per-auction price serialization, event-sourced Kafka bid streams, live WebSocket rooms, sealed-ceiling proxy resolution, capped anti-sniping timers, and KYC-verified onboarding into an auditable auction marketplace.

End-to-End Platform Workflow

  1. 1KYC Seller Onboarding & Category-Compliant Listing Approval
  2. 2Saved-Search Discovery Alerts & Live Room Registration
  3. 3Timed, Live Room, or Confidential Proxy Bidding
  4. 4Anti-Sniping Extension & Distributed Quartz Closing
  5. 51% Buyer Connection Fee Settlement (48h Deadline)
  6. 6Verified Party Introduction Room & Direct Handover

Key Capabilities & Functional Modules

Timed & Live Virtual Auction Formats

  • Runs fixed-window timed auctions alongside scheduled live virtual auction rooms broadcasting highest bids, bidder counts, countdowns, and quick-increment controls via WebSockets.
  • Auction state version numbers let reconnecting bidders synchronize missed events seamlessly from the server without stale prices.
  • Supports optional hidden reserve indicators ('reserve met' / 'reserve not met') and configurable Buy Now immediate settlement prior to competing bid thresholds.

Confidential Proxy Bidding & Anti-Sniping Engine

  • Buyers register secret ceiling amounts; the engine computes minimum winning increments without exposing maximum limits in API payloads, WebSocket frames, or logs.
  • Resolving competing proxies instantaneously in a single atomic calculation eliminates runaway bid-loop storms while honouring earlier timestamp priority on equal ceilings.
  • Anti-sniping extends closing timers when qualifying late bids enter the final window, governed by a strict maximum extension cap so auctions conclude predictably.

Category Discovery, Alerts & Fraud Prevention

  • Dynamic category-attribute filters (brand, model, year, condition, location) powered by Elasticsearch alongside throttled saved-search alerts when new listings publish.
  • Multi-tier trust verification checks identity, ownership or authenticity documents for vehicles/antiques, and blocks sellers or linked accounts/IPs/devices from shill bidding.
  • Pre-sale in-platform messaging blocks external phone/contact sharing before checkout to protect marketplace integrity.

Buyer Connection Fee & Direct Settlement Workflow

  • Upon auction close, the winning bidder pays a 1% platform connection fee within the payment window (with automatic second-chance fallback offers upon default).
  • Verified fee payment automatically exchanges buyer/seller contact credentials and opens a dedicated handover chat room while item purchase payment concludes directly between parties.

User Roles & Operational Responsibilities

Buyer

Configures saved-search alerts, joins live or timed auctions, sets confidential proxy maximums, pays connection fees upon winning, and reviews sellers.

Seller / Live Host

Publishes verified category listings with reserve/increment rules, leads scheduled live auction rooms, coordinates handover, and receives direct buyer settlement.

Moderator & Admin

Reviews listings and KYC records, monitors shill-bidding signals, handles dispute freezes or cancellations, and governs category/commission configurations.

Architecture Rules & Edge-Case Resilience

  • Locks listing prices, minimum increments, and closing rules automatically once the first valid bid is accepted.
  • Distributed locking (Quartz with ShedLock) guarantees exactly-once auction closing across clustered instances even around server restarts.
  • Fixed decimal minor-unit currency handling, masked public bidder identities ('Bidder 3'), and immutable bid audit trails guard financial accuracy and privacy.

Confirmed Technology Stack

Backend & Microservices

  • Java
  • Spring Boot
  • Spring Security
  • NestJS
  • Microservices
  • RESTful APIs
  • JWT

Frontend & Live Streaming State

  • Angular
  • WebSocket

Persistence, Coordination & Messaging

  • PostgreSQL
  • Redis
  • Apache Kafka
  • Elasticsearch
  • Quartz with ShedLock

Cloud & Delivery

  • Docker
  • Kubernetes
  • S3-Compatible Object Storage + CDN
  • CI/CD

Intended Marketplace & Revenue Value

Intended architectural and operational benefits based on system design goals

  • Unlocks true competitive price discovery for sellers of high-value, specialty, and collectible assets.
  • Boosts bidder engagement without constant manual monitoring through private proxy limits and saved-search notifications.
  • Protects marketplace trust and asset provenance through KYC checks, anti-sniping extensions, and shill-bid monitoring.
  • Delivers a clean 1% connection-fee monetization flow without holding escrow custody over high-value purchase principals.

Have a similar project in mind?

Schedule an architectural review or scoping discussion with Kode Company's engineering team.

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