Full Time

Full-Time | Remote (US) · New York, NY
Department: AI / ML
Compensation: $150,000 – $220,000 USD / year

LockedIn AI is looking for a deeply technical LLM Developer to design, build, and optimize the large language model systems powering our real-time AI copilot used by over 1 million users.

This is a core engineering role where you will directly shape how our AI listens, reasons, and responds during live interviews, coding assessments, and professional meetings.

About LockedIn AI

LockedIn AI is the #1 real-time AI interview and meeting copilot, trusted globally by over 1 million users.

We build AI-powered systems that help candidates perform better in high-stakes career moments by providing real-time assistance during interviews and professional conversations.

Our platform sits at the intersection of:

• Large language models
• Real-time inference systems
• Retrieval systems and embeddings
• High-scale production infrastructure

Role Overview

As an LLM Developer, you will own the full lifecycle of LLM-powered systems — from model selection and prompt design to inference optimization and production deployment.

You will work on systems that must be fast, accurate, and context-aware in real time. Your work directly impacts user experience during live interviews.

You are expected to think deeply about model behavior, latency, cost, and output quality — and continuously improve all four.

Key Responsibilities

LLM Application Development

• Design and build production LLM features for real-time AI assistance
• Develop prompt chains, conversation flows, and tool-use systems
• Build retrieval-augmented generation (RAG) pipelines
• Create multi-model routing systems based on latency, cost, and task type

Inference & Performance Optimization

• Optimize real-time inference pipelines for low latency
• Implement streaming responses, caching, and batching strategies
• Improve token efficiency and context window management
• Reduce cost through model routing and optimization techniques

Fine-Tuning & Model Customization

• Fine-tune models for domain-specific use cases
• Build and manage training datasets and evaluation pipelines
• Apply techniques such as LoRA, QLoRA, and RLHF
• Run experiments to compare model performance across configurations

Prompt Engineering & Quality Systems

• Design system prompts and instruction architectures
• Build evaluation frameworks for hallucination, accuracy, and relevance
• Perform root-cause analysis of model failures
• Continuously iterate on prompt and retrieval strategies

Evaluation & Monitoring

• Build LLM evaluation pipelines and benchmarks
• Monitor production metrics including latency, quality, and cost
• Detect model drift and regressions
• Optimize token usage and API efficiency

Safety & Reliability

• Implement guardrails against prompt injection and unsafe outputs
• Test adversarial inputs and edge cases
• Ensure privacy-first handling of user data
• Improve robustness of real-time AI responses

Required Qualifications

• 3+ years experience building LLM or AI systems in production
• Strong experience with RAG systems and prompt engineering
• Proficiency in Python and LLM frameworks (LangChain, LlamaIndex, or similar)
• Strong understanding of transformer architectures
• Experience with vector databases and embeddings pipelines
• Experience building APIs or backend systems for AI services
• Experience with evaluation and monitoring of ML systems

Preferred Qualifications

• Experience with real-time or low-latency LLM systems
• Background in speech + multimodal AI systems
• Experience with agentic workflows and tool-use LLMs
• Familiarity with model compression and optimization
• Experience with LLM safety, guardrails, and adversarial testing
• Contributions to open-source AI or LLM projects
• Startup or early-stage company experience

What We Offer

Equity
Meaningful early-stage ownership in the company

Impact
Your work directly powers a platform used by over 1 million users

Flexibility
Remote-first culture with optional collaboration in New York City

Growth
Fast-paced environment focused on applied AI innovation

Culture
User-obsessed, engineering-driven, and execution-focused team

Why Join Us

• Category-defining AI copilot product
• Massive global user base
• Direct ownership of core LLM systems
• Opportunity to build real-time AI at scale
• Work at the frontier of applied large language models

How to Apply

Please submit:

• Resume or CV
• Short note including:
  • Why you want to join LockedIn AI
  • Whether you have used our product
  • What improvements you would suggest
• Optional: GitHub, portfolio, or technical writing samples