Real-Time Car Search Web App Development

1. Project Title (Titel)Real-Time Car Search Web-App with Split-Screen and Phoner Dialer - Hetzner VPS Setup2. Project Description (Beschreibung)ATTENTION: You must start your application with the word "SNIPER" to prove you read the whole description. Automated generic bids without this word will be deleted instantly!I am an experienced automotive buyer looking for a highly skilled Python or Node.js developer to build a custom, private real-time car search web application. The backend will run 24/7 on a Hetzner Cloud VPS (Ubuntu). I will access the password-protected frontend via desktop Google Chrome.The core requirement is an aggressive 1-2 second scraping frequency across 3 major car trading platforms using rotating Residential Proxies (I already have an active account with Decodo / Smartproxy).To achieve this speed and minimize proxy data, you should target internal mobile app APIs (JSON endpoints) instead of parsing heavy HTML frontends.REQUIRED UI/UX ARCHITECTURE (Split-Screen Dashboard)The Google Chrome interface must be a split-screen layout using WebSockets for instant, zero-delay data transfer:Left Side (Control Center):OVERVIEW: A chronological real-time list of new listings with platform icons, thumbnail images, short titles (make, model, year), and prices. It must play an audio alert for every new vehicle.LISTING DATA: Complete vehicle specs, original description text with an automated keyword filter (highlighting bad words like "Motorschaden", "Export" in red), and a price history log.PROVIDER: Visual badges for PRIVATE vs. DEALER, location/ZIP, and a large "Click-to-Call" button. It also needs a 1-Click quick email template tool.Right Side (Live Preview):4. BROWSER BETA: A live view of the original listing page from the respective platform. Since these platforms block standard iFrames via X-Frame-Options, you must solve this either via server-side proxy mirroring or a small companion Chrome Extension that bypasses the frame protection locally.AUTOMATIC DIALER MODE (Phoner Interface)5. AUTOMATIC DIALER SWITCH: A global ON/OFF toggle switch at the top. When toggled ON, the web-app must instantly pass any newly discovered phone number to the local Windows software Phoner / PhonerLite using standard URL protocol handling (tel: or phoner:) or a CLI command via the Chrome Extension.MANDATORY REQUIREMENT: DEMO AND PRE-TESTINGYou must build and test the entire system on YOUR OWN server infrastructure first.Before any milestone release or deployment on my server, you must provide a fully functional LIVE DEMO.I need to see the 1-2 second scraping interval working live, and test the Phoner dialer integration from the demo dashboard to verify that the target platforms do not block your scraping method.If you cannot provide a working live demo showing real-time listings, the project will be cancelled. No upfront payments for unfinished code.PAYMENT STRUCTURE: STRICTLY MILESTONE-BASEDPayment will be handled strictly via Freelancer.com Milestones. No funds will be released until the specific milestone has been delivered, tested, and verified by me. The project will be split into 3 Milestones:Milestone 1 (30%): Functional Live Demo on your server showing real-time scraping (1-2s frequency) of the 3 platforms and data extraction into the basic dashboard layout.Milestone 2 (40%): Integration of the Phoner dialer functionality, the keyword filter system, and the Split-Screen "Browser Beta" solution fully working on the test environment.Milestone 3 (30%): Final migration and successful deployment on my Hetzner Cloud Server, setup of my Decodo proxies, final stress testing, and delivery of the full source code.TECHNICAL AND CODE FOUNDATIONS:You will be provided with two GitHub repositories as a technical reference: One for efficient JSON-API backend scraping and one for the Chrome Extension logic.Database (SQLite/PostgreSQL) to prevent duplicate alerts.Please apply with your estimated development hours, hourly rate, or fixed price.