Senior Software Engineer - AI Engineering

Quiet Capital; United States; On-site; USD 166,600 - 218,700; Full time

Job summary

A fintech company is seeking an experienced backend engineer to join their team in developing and enhancing an internal AI platform. The role involves building servers, operating LLM gateway infrastructure, and ensuring the shared knowledge layer is reliable for internal systems. The ideal candidate will have 5+ years of backend development experience, fluency in programming languages, and hands-on experience with LLM-powered systems. The position offers competitive salary ranges between $166,600 and $218,700 in the United States.

Qualifications

• 5+ years of backend development experience in complex, production systems.
• Hands-on experience building LLM-powered systems.
• Effective communication across technical and non-technical audiences.

Responsibilities

• Build and evolve MCP servers connecting systems and data sources.
• Expand and operate LLM gateway infrastructure.
• Ensure accurate reasoning for LLMs in Mercury's systems.

Skills

Backend development experience

Fluency across programming languages

Experience with LLM-powered systems

Understanding of AI deployment tradeoffs

High agency and self-directed

Clear communication skills

Job description

At Mercury, we're making a deliberate, company-wide bet on AI. Frontier users are already pushing boundaries—building agents, automating workflows, moving fast. But they're doing it in silos. This role exists to change that: to take those scattered experiments and turn them into shared infrastructure, shared context, and shared capability. The goal is a multiplier effect—where the most ambitious AI work inside Mercury lifts the velocity of everyone else.

What you'll do

You’ll join a team that has already started building Mercury's internal AI platform and enablement layer. Your work will be to extend, harden, and scale what's in motion, and to help partner teams adopt it.

Extend the AI platform foundation

• Build and evolve MCP servers that connect internal systems and data sources into a coherent interface for agents and engineers.
• Expand and operate our LLM gateway infrastructure: routing, rate limiting, cost attribution, and observability across teams.
• Turn early patterns into durable defaults: shared prompt libraries, guardrails, and policy-as-code so teams can move fast safely.

Strengthen the shared company knowledge layer

• Shape and maintain structured context artifacts—clean, reliable, agent‑consumable—so LLMs working in Mercury's systems can reason accurately about our domain.
• Improve internal knowledge discoverability and retrieval so both humans and agents can quickly find accurate answers.
• Partner with domain teams to standardize key sources of truth, and keep them fresh.

Enable faster prototyping and iteration across the company

• Build and refine sandbox environments and tooling that let engineers experiment with AI safely and at speed.
• Create self‑service scaffolding so non‑engineers—PMs, ops, finance—can prototype and deploy AI‑powered workflows with minimal hand‑holding.
• Build playgrounds and evaluation harnesses so internal AI agents can be tested and iterated in controlled environments before hitting production.

This list is illustrative. Priorities will shift as we learn; the right person will help choose the next highest‑leverage work.

The ideal candidate

• Has 5+ years of backend development experience in complex, production systems—you've built things that other engineers depended on.
• Is fluent across programming languages and can navigate platform engineering, infrastructure, and developer tooling without needing a map.
• Has hands‑on experience building LLM‑powered systems—RAG pipelines, agents, eval frameworks—and has shipped at least one of these to production.
• Understands the real tradeoffs in AI deployments: cost modeling, observability, latency, and safety—not just the exciting parts.
• Is high‑agency and self‑directed. You can operate effectively without tightly‑defined scope, find the highest‑leverage work, and get it done.
• Communicates clearly across technical and non‑technical audiences—you can explain what you built and why it matters.

The total rewards package at Mercury includes base salary, equity, and benefits. Our salary and equity ranges are highly competitive within the SaaS and fintech industry and are updated regularly in accordance with the most reliable compensation survey data for our industry. New hire offers are made based on a candidate’s experience, expertise, geographic location, and internal pay equity relative to peers.

Our target new hire base salary ranges for this role are the following:

• US employees (any location): $166,600 – $218,700
• Canadian employees (any location): CAD 157,400 – 206,650

Mercury values diversity & belonging and is proud to be an Equal Employment Opportunity employer. All individuals seeking employment at Mercury are considered without regard to race, color, religion, national origin, age, sex, marital status, ancestry, physical or mental disability, veteran status, gender identity, sexual orientation, or any other legally protected characteristic. We are committed to providing reasonable accommodations throughout the recruitment process for applicants with disabilities or special needs. If you need assistance, or an accommodation, please let your recruiter know once you are contacted about a role.