ML Research Engineer, Trust & Safety

Realmlabs; Sunnyvale (CA); Hybrid; USD 180,000 - 320,000; Full time

Benefits offered by this job

Founding equity

Medical insurance

401-K

Job summary

RealmLabs is seeking a founding ML researcher with strong experience in trust and safety for LLMs. You will design experiments, author papers, and build end-to-end systems contributing to core product capabilities as part of the founding team.

The role emphasizes ownership, experimentation, and delivering concrete signals for model alignment and robustness, with a focus on multimodal LLMs and prompt-security challenges.

Qualifications

• Demonstrated research experience with leadership in a field related to ML safety and trust.

Responsibilities

• Designing and executing research experiments on LLM trust and safety
• Reading, synthesizing, and producing research papers and technical write-ups
• Building, running, and owning systems end-to-end
• Contributing to core product capabilities as a founding team member

Skills

PyTorch

HuggingFace

Transformers

Datasets

Applied deep learning

LLM fine-tuning

Education

PhD in a technical field

Tools

Docker

vLLM

Triton Inference Server

Job description

Role Overview

This is an individual contributor role blending ML research, applied ML, and software engineering. Topics include trust and safety challenges for large language models (LLMs) and multimodal LLMs (MM-LLMs):

• Prompt injection attacks and adversarial robustness


• Safety alignment and guardrails


• Privacy and confidentiality


• (Mechanistic) interpretability

Responsibilities

• Designing and executing research experiments on LLM trust and safety


• Reading, synthesizing, and producing research papers and technical write-ups


• Building, running, and owning systems end-to-end


• Contributing to core product capabilities as a founding team member

What We're Looking For

ML & Research

• Demonstrated research experience; PhD in a technical field strongly preferred


• Ability to identify relevant research questions and find answers through literature review or experimentation


• First-author or major contributing authorship on peer-reviewed publications; please list these on your resume or cover letter


• Hands-on experience with PyTorch, HuggingFace (Transformers, Datasets), and applied deep learning


• Experience training and evaluating deep learning models


• Nice to have: LLM fine-tuning, multimodal LLMs, PEFT/LoRA


• Nice to have: Familiarity with ML interpretability methods (mechanistic interpretability, sparse autoencoders, linear probes, NLP/Vision interpretability)

Software Engineering

• Proficiency in Python; experience with Jupyter notebooks


• Unix environments, Git, and basic AWS/GCP usage


• Nice to have: Programming languages well-roundedness; experience with statically-typed and functional programming languages


• Nice to have: Familiarity with (LLM) deployment tooling like Docker, vLLM, Triton Inference Server or similar

Logistics

• Available to start within 2 months


• Role may include limited on-call responsibilities tied to production ownership

Additional Information

• This is a founding, high-ownership role with direct impact on core product capabilities.


• You will be expected to build, run, and own systems end-to-end.


• The role may include limited on-call responsibilities aligned with production ownership.

About RealmLabs

• AI systems misbehave: they leak sensitive data, get manipulated through prompt injections, or behave in ways their builders never intended. RealmLabs is building the infrastructure to detect, debug, and prevent these behaviors.


• Our approach is to secure AI from within: observing models from the inside, extracting signals relevant to their behavior and misbehavior, and patching them on the inside, rather than relying on input/output filters or external guardrails.


• We are a pre-seed startup and a finalist in the RSAC 2026 Innovation Sandbox. Our customers include Anthropic, a leading ride-sharing platform, and a Big 3 management consulting firm.


• This is a founding engineer role with meaningful equity at an early-stage company.

Compensation & Benefits

• Market aligned compensation and benefits.


• Founding equity (Equity is a significant component of this role and will be discussed)


• Medical, Dental, Vision, Life insurance, 401-K, In-office lunch etc.

Visa sponsorship

• We do sponsor visas! However, we aren't able to successfully sponsor visas for every role and candidate. But if we make you an offer, we will make all reasonable effort to get you a visa, and we retain an immigration lawyer to help with this.