Bill Pilot API

A production-style subscription tracking API that emails renewal reminders before recurring payments hit, built on Node.js and Express.

• REST API & Authentication: A versioned Express API over MongoDB Atlas with stateless JWT sessions, bcrypt password hashing, and a transaction-wrapped sign-up so a failed write can never leave an orphaned account
• Durable Reminder Workflows: A durable Upstash QStash workflow sleeps for days at a time and wakes to send Nodemailer reminders 7, 5, 2, and 1 day before renewal, with every step wrapped for idempotency so retries never send a duplicate email
• Security & Rate Limiting: An Arcjet shield and token-bucket limiter run ahead of routing on every request, turning bot traffic and bursts into 403s and 429s before they reach a controller
• Data Modelling: Validated Mongoose schemas with a pre-validate hook that derives each renewal date from the start date and billing frequency, and marks past-due subscriptions expired on write