I need a complete online auction module for cars that runs off Google Sheets and its built-in Apps Script. The spreadsheet will act as the single source of truth, while a lightweight web or App Script UI lets bidders interact in real time. Core workflow – I enter vehicle data once in the sheet; the module pushes it instantly to the live auction page. – Registered bidders see current price and can place new bids that write straight back to the sheet. – Every bid triggers instant Email, SMS and WhatsApp alerts through a phone-connected gateway (Wi-Fi/app bridge is fine). – When a new vehicle goes live, all subscribed users receive a broadcast notification. Essential features (deliverables) 1. Real-time bidding with live refresh; last 20 bids always visible. 2. Reserve-price protection and clearly shown auction end time. 3. User registration, login and a mandatory “Tick to accept Disclaimer” step before any bid. 4. Market-price panel displaying Excellent / Good / Poor estimates pulled from a helper sheet. 5. Vehicle info page that includes: website link, prominent remarks box, and an optional entry fee that I can log manually or charge via PayPal and Stripe. 6. Multilingual UI: English by default plus an Urdu version (I will supply the Urdu text). 7. Admin controls inside the sheet for adding cars, setting reserves, closing auctions and exporting results. Acceptance criteria • All data reads/writes remain in Google Sheets with no broken formulas or script errors. • Email, SMS and WhatsApp alerts are sent and logged for every bid, new-listing broadcast and auction close. • Bid latency stays under two seconds for the first 100 simultaneous users in a simple load test. • Code, triggers and any external libraries are documented in-line and in a short setup guide so I can maintain the system myself. Minimum bid increment set by admin such as 10,000 rupees Bids lower than present highest bids rejected and bidder gets an error message Bidder can set their maximum bid and system confirms they are the highest bidders and get notifications when out bidded option to take deposits before allowing to bid, manually or via PayPal, stripe ect If you can keep everything inside the Google ecosystem (Sheets, Apps Script, possibly a lightweight HTML + CSS front-end served from Script) while meeting the above points, this project is ready to start.