Fractional Billing & Accounts Receivable (AR) Operations Specialist

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.

Key Responsibilities

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 & Systems 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

Requirements

• 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., QuickBooks, NetSuite, 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

Preferred Qualifications

• 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

Why Join

• Work at the forefront of AI innovation

• Help operationalise finance infrastructure for a rapidly scaling AI lab

• Flexible fractional engagement with meaningful ownership

• Direct impact on revenue operations and cash flow strategy

We consider all qualified applicants without regard to legally protected characteristics and provide reasonable accommodations upon request.

Contract and Payment Terms

• You will be engaged as an independent contractor.
• This is a fully remote role that can be completed on your own schedule.
• Projects can be extended, shortened, or concluded early depending on needs and performance.
• Your work at Mercor will not involve access to confidential or proprietary information from any employer, client, or institution.
• Payments are weekly on Stripe or Wise based on services rendered.
• Please note: We are unable to support H1-B or STEM OPT candidates at this time.

About Mercor

Mercor partners with leading AI labs and enterprises to train frontier models using human expertise. You will work on projects that focus on training and enhancing AI systems. You will be paid competitively, collaborate with leading researchers, and help shape the next generation of AI systems in your area of expertise.