Software Engineer, Applied AI Systems

Mercors mission is to organize human intelligence for the AI economy. We build the infrastructure that enables frontier AI labs and enterprises to train evaluate and improve AI on real-world professional work. More than five million experts have joined our network and we pay out over $5 million daily for their knowledge and expertise.

We built our training and evaluation infrastructure alongside the worlds leading AI labs. Now were bringing those capabilities to enterprises across industries enabling them to train evaluate and improve AI using their own expertise and standards. Our APEX benchmarks measure how AI performs on economically valuable work while our enterprise evaluations and post-training capabilities turn those insights into measurable improvements across real-world workflows.

Our work sits at the intersection of frontier AI human expertise and real-world application. Were solving problems few companies have encountered with the opportunity to influence what the worlds most advanced AI systems become capable of doing. Were looking for people who bring different perspectives take ownership exercise sound judgment and hold themselves to an exceptionally high standard. Youll have the opportunity to do consequential work alongside talented colleagues who challenge one another collaborate openly and share a commitment to excellence.

Mercor is profitable and recently raised a $750 million Series D at a $20 billion valuation. We work in person five days a week in San Francisco New York and London.

The Applied AI org builds the systems that turn human expertise into training data for frontier models task pipelines expert workflows evaluation infrastructure and the services that tie them together. We have synthetic pipelines and modular quality control systems that run in unison to generate highest quality tasks and at scale. All of it runs on backend systems that have to stay correct fast and observable while the volume behind them grows every month.

As a Software Engineer on Backend Systems youll own services in that stack: designing the data models building the APIs services data pipelines that move work through the platform. This is a build role. Youll take a problem thats roughly scoped make the design calls ship it to production and own it afterward.

Were hiring for depth in backend fundamentals rather than any particular domain. If youve built and operated real services handled the schema migration that couldnt take downtime found the query that fell over at 10x traffic designed the retry logic that made a flaky dependency invisible to users or build a system that recover when things break thats the experience that matters here. Youll work with a talent dense group of engineers who will review your designs and push your thinking and youll be expected to grow into owning larger surfaces quickly.

• Design build and operate backend services in the Applied AI stack including APIs data models background jobs and the pipelines that connect them.

• Own features end to end: scope the problem write the design ship the code instrument it and keep it healthy in production.

• Build and tune high-throughput data and job pipelines: queuing batching idempotency retries and backpressure.

• Make the system fast and reliable by adding failure recovery in pipelines profile hot spots Agent token and cost attribution caching issues and set latency error cost budgets you actually hold to.

• Instrument what you ship: observability metrics logging tracing and alerts that proactively catch problems.

• Work on modern cutting edge tools libraries and frameworks.

• Manage and launch 10s of 1000s of containers sandbox environments manage resource allocation and system health.

• Manage infrastructure as code using Terraform.

• Participate in on-call for the systems you own debug production incidents and write up what you learn in RCCA.

• Write clear design docs and give useful code review we make technical decisions in writing and expect everyone to take part.

• Work directly with product operations and research partners to turn ambiguous requirements into systems that ship.

• 25 years of professional backend engineering experience building and operating production systems.

• Strong fundamentals in backend engineering: data structures algorithms concurrency and writing code thats clear enough for the next person to change.

• Hands-on experience with API design - REST gRPC or GraphQL and an understanding of versioning contracts and backward compatibility.

• Solid database skills: relational data modeling indexing query performance transactions and isolation and safe migrations. Familiarity with at least one NoSQL or key-value store and when its the right choice.

• Practical experience with distributed systems basics: queues and event streams caching idempotency rate limiting and designing for partial failure.

• Experience with Data Orchestration and workflow management systems like Airflow Temporal Dagster.

• Be able to roll your sleeves up and dig deeper into the lower level infrastructure issues container permissions logs traces and find the needle in the haystack.

• Experience running services in production: containers CI/CD monitoring and alerting and debugging issues under real traffic.

• Comfort with ambiguity you can take a loosely defined problem ask the right questions and come back with a plan.

• Genuine excitement for agentic development and new technology fluency with modern AI dev tools (e.g. Claude Code Cursor Copilot) and a real passion for writing good code.

• Clear written and verbal communication. High ownership pragmatism and a bias toward shipping.
  

• Experience building or integrating with LLM-backed services in production (evaluation orchestration or serving).

• Familiarity with AI infrastructure providers like Modal Fireworks Baseten Temporal

• Bi-annual performance bonus structure

• Generous equity grant vested over 4 years

• Up to $15k Relocation bonus

• $10K housing bonus (if you live within 0.5 miles of our office)

• $1.5K monthly stipend for meals

• Free Equinox membership

• $200 monthly laundry reimbursement

• $200 monthly personal wellness reimbursement

• Health Dental Vision insurance

Mercor is an Equal Opportunity Employer and is committed to providing equal opportunity to all employees and applicants. Mercor does not discriminate based on actual or perceived race color creed religion national origin ancestry citizenship status age sex or gender (including pregnancy childbirth related medical conditions and lactation) gender identity or gender expression sexual orientation marital status military service and veteran status disability protected medical condition as defined by California or local law genetic information or any other characteristic protected by applicable federal California or local laws and ordinances. Further Mercor prohibits discrimination harassment and retaliation based on any combination of protected characteristics. This Policy applies to all areas of employment including recruitment hiring training promotion compensation benefits discipline termination and all other privileges terms and conditions of employment. This Policy and the law prohibit employment discrimination against any employee or applicant based on any legally protected status.

Required Experience:

IC