Software Engineer, Payments

Mercor•San Francisco, CA

7h•Onsite

About The Position

Mercor is defining the future of work. We partner with leading AI labs and enterprises to provide the human intelligence essential to AI development. Our vast talent network trains frontier AI models in the same way teachers teach students: by sharing knowledge, experience, and context that can't be captured in code alone. Today, more than 30,000 experts in our network collectively earn over $2 million a day. Mercor is creating a new category of work where expertise powers AI advancement. Achieving this requires an ambitious, fast-paced and deeply committed team. You’ll work alongside researchers, operators, and AI companies at the forefront of shaping the systems that are redefining society. Mercor is a profitable Series C company valued at $10 billion. We work in-person five days a week in our new San Francisco headquarters. Payments is the core infrastructure of our marketplace, not a back-office function. As our AI systems scale to evaluate, place, and compensate millions of workers across geographies, we are investing in making our financial systems deterministic, observable, and resilient because the models that route talent are only as good as the infrastructure that pays them. In a matter of months, we've gone from moving hundreds of thousands of dollars to hundreds of millions across our platform: what used to work at $200K won't work at $200M. The mission of the Payments group at Mercor is to be the financial and commercial backbone of the company. We ensure that: Money moves deterministically and reliably at scale Failures are surfaced proactively, not reactively Ledger, payout, and settlement systems are observable end-to-end Root causes are fixed, not patched Automation replaces manual intervention wherever possible We operate at the intersection of Engineering, Finance, Product, Ops, and Fraud. Our mandate is to transform payments from manual orchestration into resilient financial infrastructure. This role exists to help build the financial backbone that supports the next 1000x. We are looking for a senior engineer to help harden and scale Mercor’s payments platform. This role requires someone who understands that payments infrastructure is both a technical and financial system, where correctness matters as much as uptime. We’ve grown from ~$200K in payment volume to ~$200M in a short window. The systems weren’t designed for this scale, and that’s exactly why this role matters. If you like building planes mid-flight, this will feel familiar. We are no longer building “payment features.” We are designing sustainable financial infrastructure for a rocketship. If that sounds energizing, keep reading. You’ll be working at the core of Mercor, scaling the core systems used by thousands of experts working on the frontier of AI.

Requirements

5+ years in building scalable backend systems, with a strong preference for experience in high-stakes domains such as payments, fintech, billing, or financial infrastructure.
3+ years of industry experience in backend/platform engineering (or equivalent), including ownership of production systems.
Demonstrated ability to integrate with and manage third-party payment gateways (e.g., Stripe, Adyen) and/or direct banking APIs.
Understanding of financial regulations, including adherence to PCI-DSS, and the secure handling and encryption of sensitive banking and customer data.
3+ years of professional experience building around: transactional databases like MySQL or PostgreSQL compiled languages like Go, Rust, or C++ Experience with message queues or streaming platforms (e.g., RabbitMQ, SQS, Kafka). distributed systems frameworks like temporal, k8s, etc..
Proven ability to manage and operate production systems under significant load. This includes balancing the velocity of development with maximum reliability, evidenced by a commitment to detailed observability and sophisticated payment agents.
Comfortable working with high intensity in fast-growing, ambiguous environments. Thinks in terms of systems and strategic solutions, not just individual tickets.

Responsibilities

Flow-level observability across payout → settlement → reconciliation
Reliability engineering for distributed payment systems
Instrumentation and monitoring of financial primitives (ledger, payout orchestration, settlement ingestion)
Automation to eliminate manual treasury and payout workflows
Root-cause driven system redesign
Automating payout orchestration (no more human-triggered scripts)
Building a real operational ledger (immutable, auditable, boringly correct)
Designing settlement ingestion + reconciliation pipelines
Improving observability across payout → processor → bank flows
Eliminating recurring payment bugs at the root cause
Reducing manual treasury overhead
Abstracting processor dependencies so we’re not locked in