Software Engineer Job at ACT Consulting, Inc. in San Francisco

ACT Consulting has an immediate need for a Software Engineer - Full-Stack role located in San Francisco, CA with our direct client.
ACT Consulting is a leader in the staffing industry providing candidates on a national basis for contract, contract to hire, and direct hire engagements while maintaining the highest regard for people, integrity, and customer satisfaction. Our clients are mostly Fortune 1000 companies, primarily in the areas of Information Technology, Engineering, Professional, Accounting and Finance.

Please take a moment to review the job description. If this is something you are interested in, please send a copy of your resume to mark@act-info.com or contact me directly at 203-302-0562.

Job Title: Software Engineer - Full-Stack with Backend & LLM Focus
Location: San Francisco, CA (On-site)
Employment Type: Full-Time
Salary: $150,000 - $300,000 base (DOE)
Visa Sponsorship: H-1B, O-1, OPT

Company Introduction
This stealthy YC-backed Series A startup is building next-gen, human-like voice AI agents that fully automate customer support for major B2C brands in food delivery, crypto, and beyond. Their AI handles over a million support tickets per month, with multi-year contracts and backing from Y Combinator, Nexus VP, and other top-tier investors. Bonus flex: Built X1 series LLMs (fine-tuned Llama2 70B models, 8k & 32k context lengths). On-prem, fast, secure-beating Claude 2 on MT-Bench.

Role Overview
As a Software Engineer, you'll ship, own, and scale LLM-powered products end-to-end- partnering closely with founders. If you're tired of being a faceless cog and want to see your code in action from launch to customer experience, this is your playground.

Core Responsibilities
• Ship & own product features and full product lines within an LLM-based stack.
• Architect scalable, low-latency, secure backend systems to power real-time voice AI.
• Drive product vision-translate big ideas into technical sprints and releases with founders.
• Deliver high-quality, maintainable code-you own the reliability and performance.
• You're not just coding-you're powering a trillion voice interactions and automating enterprise-scale support.
• This is an ownership-first role in a YC-backed team moving at breakneck speed.
• Work intimately with technical founders in a small, high-impact team.
• Push the envelope with cutting-edge LLM tech-think Toolkit meets Olympus.
• Secure, fast, on-prem solutions (X1 series) that outperform Claude 2 lend serious tech street cred.

Required Background
• 3-5 years building and deploying LLM-based or high-performance backend systems.
• Full-stack capabilities, with strong backend experience.
• Deep technical ownership and comfort in lean, rapidly evolving environments.
• Immersed in LLM tooling-deployment, fine-tuning, API integration, scaling, and latency optimization.
• Proactive communicator-you can work alongside founders and cross-functionalstakeholders.
• Experience building in production, not hobby projects.
• Junior candidates: Need elite pedigree (top-tier CS school, ~3.9+ GPA), LLM/backend experience, and X-factor energy.
• Senior candidates: Less credential-bound; we want exceptional accomplishments (exfounder, deep LLM production experience). More equity for those who over-deliver.
• Ideal candidates are engineers who LOVE shipping LLM-powered features in production-bonus if you've launched before.

Compensation & Perks
• Base Salary: $150K-$300K
• Health, dental, and vision insurance
• Equinox gym membership, wellness stipend and on demand meals/snacks/coffee
• Competitive Equity + fast promotion track
• High-velocity, high-impact, founder-level collaboration