Website is built with NextJs. The models are all built with NodeJs--custom backtester framework, and the execution framework and data fetchers are also in Node and leverage a few open source libraries and currently only works with Interactive Brokers.
We just launched mid December, and currently have 16 paying subscribers and 178 free members. MRR about $2500. The Platinum plan can be either implemented via API, email notifications or a managed account in which case after some legal paperwork, we set up a second user in Interactive brokers with trading authority that executes trades based on the signals (hedging via ES futures).