Staff Software Engineer - Agent Architecture

Role Description

We build agentic AI products that our customers interact with across different modalities. These agents sit on top of the same money-movement platform that handles real funds for businesses in regulated industries, so they have to be safe, compliant, and predictable in ways most consumer AI products are not.

We're looking for a Staff Engineer to own the architecture and implementation of these agents end-to-end. This is a builder role for someone who has shipped agents to production at scale, not just used them. You will define how we build agents at PayNearMe: the frameworks, the integration patterns with our existing systems, the guardrails around money and PII, and the testing/eval/observability loop that lets us improve agents safely over time.

Our core platform stack is Ruby on Rails with MySQL (monolith) plus Go microservices on AWS/Kubernetes, with Datadog for observability. Our agents interact with consumers and business partners across a wide variety of use cases.

What you'll do

• Define and build the agent platform used across applications at PayNearMe.
• Own the architectural direction for agentic AI at PayNearMe in partnership with other engineering leaders.
• Produce and maintain architecture documentation (current state, target state, migration plan).
• Design, build, and ship production agents—including voice and chat agents for a wide range of payment-related activities.
• Make and defend the "what kind of intelligence goes where" decisions.
• Design and operate the agent lifecycle as a closed loop: testing, offline evals, online evals, observability, scoring, and feedback paths.
• Own the unit economics of agent interactions.
• Build the guardrails that make agents safe in a payments context.
• Treat voice as its own modality, not a text agent with a microphone.
• Partner with Security, Compliance, and Legal to ensure agent behavior meets regulations.
• Raise the bar across the org for agent engineering.
• Partner with the Engineering Managers, Product, and other Staff peers to shape the roadmap.

Qualifications

• 8+ years of software engineering experience, with Staff-level scope.
• Demonstrated experience shipping agentic AI systems to production.
• Hands-on experience with at least one modern agent framework (LangGraph, or comparable).
• Deep, lived experience with the full agent lifecycle.
• Strong system design fundamentals.
• Comfortable working in a Ruby on Rails / MySQL environment.
• Clear communication and strong judgment in high-stakes environments.
• Ability to move between high-level architecture and hands-on coding.

Requirements

• Experience shipping voice agents specifically.
• Hands-on experience building and shipping voice-enabled applications.
• Experience designing agents that combine multiple styles of intelligence.
• Payments/fintech experience, or other regulated/high-integrity domains.
• Experience building and operating evaluation infrastructure.
• Experience designing agent platforms with multi-tenant configuration.
• Experience adversarially testing LLM-based systems.
• Experience optimizing the unit economics of LLM-based products.
• Experience with observability for non-deterministic systems.
• Experience integrating AI capabilities into a Ruby on Rails monolith.

Benefits

• Competitive salary and benefits with growth-company options grant.
• Fast-paced and professional work culture.
• Stock options with standard startup vesting - 1 year cliff; 4 years total.
• $50 monthly communication expense stipend.
• $250 stipend to enhance your WFH setup.
• Reimbursement for peripheral equipment.
• Premium medical benefits including vision and dental (100% coverage for employees).
• Company-sponsored life and disability insurance.
• Paid parental bonding leave.
• Paid sick leave, jury duty, bereavement.
• 401k plan.
• Flexible Time Off (typically ~3-4 weeks per year).
• Volunteer Time Off.
• 13 scheduled holidays.