# Applied AI Engineer
**Company:** [Twenty](https://hotfix.jobs/companies/twenty)
**Location:** Washington, DC
**Experience:** 4+ years
**Skills:** Python, PyTorch, TensorFlow, JAX, LangChain, LangGraph, Crewai, Pydantic-Ai, RAG, vLLM, Kubernetes, Docker, Pgvector, Chromadb, Pinecone
**Posted:** 2025-09-04
> Builds and deploys language model-powered systems for cyber national security applications, including fine-tuning LLMs, RAG systems, and production inference. Requires 4+ years ML experience, Python/PyTorch proficiency, and LLM post-training expertise.
## Job Description
## Responsibilities
- Create, clean, and maintain high-quality training and evaluation datasets for specialized AI use cases.
- Fine-tune language models (small specialized through medium foundation models) for mission needs.
- Implement post-training and alignment approaches to improve task performance and reliability.
- Build retrieval-augmented generation (RAG) systems that ground model outputs in external knowledge.
- Develop and optimize model serving infrastructure for production deployments.
- Design evaluation frameworks and test harnesses to measure quality, latency, and regressions.
- Integrate AI capabilities into applications and workflows using modern orchestration frameworks.
- Collaborate with cross-functional partners to identify high-leverage use cases and deliver solutions.
- Produce clear technical documentation for models, datasets, and operational processes.

## Requirements
- 4+ years of professional software development experience building and supporting ML/AI-enabled applications.
- Strong Python skills and deep learning experience with **PyTorch**, **TensorFlow**, or **JAX**.
- Hands-on experience with LLM post-training methods (e.g., continued pre-training, SFT, RLHF, DPO, PPO, GRPO).
- Experience curating, cleaning, and preprocessing datasets for training and evaluation.
- Working knowledge of relational, graph, and vector database concepts.
- Experience designing or using evaluation metrics and testing procedures for LLMs and agents.
- Experience integrating LLM/agent systems using frameworks like **Pydantic-AI**, **LangChain/LangGraph**, or **CrewAI**.
- Bachelor’s degree in Computer Science, Software Engineering, or a related field (or equivalent practical experience).

## Nice To Haves
- Deployed models to production and supported them through real-world usage and incidents.
- Experience with distributed training systems and performance debugging at scale.
- Implemented quantization or other optimization techniques to improve inference efficiency.
- Strong prompt engineering and model alignment instincts for reliability and control.
- Experience building MLOps/LLMOps/AgentOps practices (versioning, rollout, monitoring).
**Apply:** https://hotfix.jobs/jobs/applied-ai-engineer-at-twenty-eae8b2a7-d45f-4d51-85b2-b83534490e16
**Canonical:** https://hotfix.jobs/jobs/applied-ai-engineer-at-twenty-eae8b2a7-d45f-4d51-85b2-b83534490e16