Crypto trading bot with multi exchange APIs

Crypto trading bot that will use API datafeed to make buy / sell orders on multiple cryptocurrency exchanges simultaneously. Choose API for stability, speed, compliance with rate limits, and availability at the exchanges (websocket, REST, FIX...). Platform desired is a web app that can be hosted in the cloud where I can login and run the app. App can also be an executable that can run locally on Linux/macOS/Windows. Developer must have solid understanding of cryptocurrency exchange APIs and prefer direct experience developing trading platforms. Milestones for payment will be established. Only serious applicants with required background need apply. References or examples demonstrating background welcome.