Verifiable car rental search powered by Arbitrum Stylus — ranking 100+ vehicles by 7 weighted criteria on-chain.
RentalRide is a decentralized car rental aggregator with verifiable search. Users set weights for 7 criteria (price, mileage, power, rating, year, interior, fuel type), and a Stylus smart contract written in Rust computes the best vehicle on-chain. Unlike traditional aggregators where a central server decides, every calculation is public and reproducible. Deployed on Robinhood Chain Testnet, the system stores 100+ cars in a Solidity bridge and delegates ranking to a Stylus (WASM) contract — 10-100x cheaper than Solidity for compute-heavy logic. Includes a Spring Boot REST API, Web3j integration, and a slider-based frontend.**Problem:** Traditional rental aggregators use opaque server-side ranking. Users cannot verify why one car is shown over another. Advertisers can pay for placement. Prices can be manipulated. The algorithm is a black box. **Solution:** RentalRide moves the ranking logic to the blockchain using Arbitrum Stylus. Users set weights for 7 criteria. A Rust smart contract computes the best car on-chain. Every calculation is verifiable. Nobody — not even the platform owner — can secretly change the formula. **Architecture:** - **Stylus (Rust/WASM):** `car_ranker` contract computes weighted scores for 7 criteria. Size: 11.9 KB. Deployed at `0xab304a3c48fd38492396d3719a8b2d16def14b8c` on Robinhood Chain Testnet. - **Solidity:** `CarBridge` contract stores 100+ cars, builds flat arrays, delegates to Stylus. Deployed at `0x484cB35720a9bB6fcEA175e041A221408d01eC02`. - **Backend:** Spring Boot (Java 21) + Web3j 4.14.0. REST API with cache preload and scheduled refresh. - **Frontend:** HTML + vanilla JS with weight sliders. **Why Stylus:** Ranking 100+ cars by 7 weighted criteria in Solidity would be prohibitively expensive. Stylus computes in 10-100x cheaper, making on-chain ranking economically viable. This is the core innovation. **Deployed on:** - Robinhood Chain Testnet (Chain ID 46630) - RPC: https://rpc.testnet.chain.robinhood.com **Demo:** - Live: http://194.5.152.242:8080/ - GitHub: https://github.com/MAFSC/RentalRide
Self-funded. No external capital raised. Open to pre-seed conversations with ecosystem funds and angels interested in verifiable computation infrastructure for RWA and aggregation use cases.
