Remote Fractional Billing & Accounts Receivable; AR Operations Specialist - AI Trainer

Mercor is hiring a Fractional Billing & AR Operations Specialist on behalf of a fast‑growing AI research lab. This organisation partners with enterprises, research institutions, and venture‑backed startups to deliver cutting‑edge AI solutions. As the company scales, they are seeking an experienced billing and accounts receivable professional with a background in professional services environments (consulting, legal, advisory, or similar). This role will bring structure, accuracy, and operational rigour to client billing, collections, and revenue tracking processes.

This is an ideal opportunity for a detail‑oriented finance operator who thrives in high‑growth environments and can build scalable billing systems while maintaining strong client communication standards.

• Billing Operations
  • Own end‑to‑end client invoicing cycles, including time‑and‑materials, milestone‑based, and retainer billing structures.
  • Ensure accurate tracking of billable hours, project codes, and client‑specific terms.
  • Partner with internal stakeholders (finance, operations, client leads) to validate invoice inputs.
  • Maintain clear documentation of billing policies and workflows.
• Accounts Receivable (AR) Management
  • Monitor outstanding invoices and proactively manage collections.
  • Lead professional, client‑facing communication regarding billing inquiries and payment follow‑ups.
  • Maintain AR aging reports and provide visibility into cash flow forecasts.
  • Identify patterns in payment delays and recommend process improvements.
• Process & System Optimization
  • Assess and improve billing systems, tools, and reporting workflows.
  • Implement scalable controls to support growth in client volume.
  • Support monthly revenue reconciliation and financial reporting.
  • Ensure compliance with contractual terms and internal financial controls.

• 5+ years of experience in billing and AR operations.
• Prior experience in professional services environments (consulting firms, law firms, advisory practices, or similar).
• Strong understanding of:
  • Time‑based and project‑based billing models.
  • Revenue recognition fundamentals.
  • AR aging and collections workflows.
• Experience working with accounting platforms (e.g., Quick Books, Net Suite, Xero, or similar).
• Excellent written communication skills for professional client correspondence.
• High attention to detail and strong process discipline.
• Ability to work independently in a fractional capacity.

• Experience supporting venture‑backed startups or high‑growth technology companies.
• Familiarity with SaaS or AI services billing structures.
• Experience building billing processes from early‑stage or scaling environments.
• Background in financial reporting or FP&A collaboration.

• Work at the forefront of AI innovation.
• Help ope rationalise finance infrastructure for a rapidly scaling AI lab.
• Flexible fractional engagement with meaningful ownership.
• Direct impact on revenue operations and cash flow strategy.

Remote Fractional Billing Accounts Receivable AR Operations Specialist AI Trainer 75100 per hour
• Allen, Texas, US