Backend Engineer (MongoDB/TS/Stripe/Clerk) – PT Freelance - Worldwide

Role Overview

Join Budget Mentor, a rapidly expanding SaaS platform, as our dedicated Backend Engineer. You'll play a crucial role in enhancing our infrastructure, focusing on Stripe billing, user permissions, and core business logic. We aim to streamline compliant, audit-ready grant budgets, beginning with NSF grants and scaling to larger government programs.

Responsibilities

• Billing & Metered Usage:

  • Develop and manage Stripe metered billing logic.
  • Implement usage-based billing at specified percentages monthly.
  • Handle card collection, failed payment retries, and upgrade triggers.
  • Automatically adjust billing rates based on user activity without service interruption.
  • Ensure full billing visibility and transparency for organization owners using Clerk's components.

• Notifications & Grace Periods:

  • Trigger and manage email/web notifications for billing issues, role reminders, budget warnings, and grace period countdowns.
  • Notify users of workspace billing thresholds, failed payments, and actions impacting organizational charges.

• General Backend Logic:

  • Develop and manage core business logic for workspace creation, organization management, and multi-user roles.
  • Implement grant locking, soft caps, and permissions enforcement.
  • Build internal APIs to expose backend data to the frontend.
  • Write and maintain clean, well-documented services and functions.

Required Skills

• 5+ years of experience in building backend logic for production SaaS systems.
• Proven expertise with Stripe, especially metered billing.
• Proficiency in working with multi-organization, multi-user role systems.
• Strong experience in noSQL database design, particularly MongoDB Atlas.
• Ability to think clearly and take strong ownership of tasks without constant supervision.
• Familiarity with writing internal APIs to support frontend features.
• Comfortable working independently or collaboratively with frontend engineers and product founders.

Nice to Have

• Experience in shipping backend systems involving financial transactions, access control, or tiered usage.
• Experience working on products with complex billing triggers.