Senior Machine Learning Engineer

Affinity.co; San Francisco (CA); On-site; USD 160,000 - 235,000; Full time

Benefits offered by this job

Health benefits

401(k) program

Learning & Development budget

Wellness & remote support

Job summary

Affinity is seeking a Senior Machine Learning Engineer to join the AI Platform team in San Francisco, New York, or US Remote. You will design and deploy ML-powered private capital relationship insights and recommendations, collaborating with data engineers, software engineers, and product managers to scale the platform.

You will own end-to-end ML pipelines, from feature engineering to model deployment and observability, focusing on information retrieval and ranking systems for large-scale

Qualifications

• 5+ years of software engineering and/or ML experience in production.
• Hands-on experience building ranking or recommendation systems at scale.
• Strong understanding of ML techniques including clustering and decision trees.
• Experience serving ML models for streaming and batch inference at scale.

Responsibilities

• Own the full ML lifecycle from ideation to production, including feature engineering, deployment, and observability.
• Translate business needs into robust ML system designs and requirements.
• Build and scale ranking and recommendation infrastructure, starting with off-the-shelf models and evolving to custom solutions.
• Tackle information extraction, storage, and retrieval challenges across structured and unstructured data.
• Collaborate with product, infra, data engineering, and software teams to deploy high-scale ML systems.

Skills

5+ years experience

Ranking systems

Python

ML in production

Tools

PyTorch

Scikit-learn

Vector/Graph DBs

Job description

Affinity stitches together billions of data points from massive datasets to create a powerful, accurate representation of the world's professional relationship graph. Based on this data, we offer our users the insights and visibility they need to nurture and tap into the opportunities in their team's network.

This role is part of the AI Platform team, which owns the AI services that power Affinity's industry-leading relationship intelligence platform. We extract and retrieve information from billions of structured and unstructured data points to deliver actionable insights to customers.

As a Senior Machine Learning Engineer, you will collaborate with data engineers, software engineers, and product managers to shape the future of private capital's leading CRM platform. You will design and build AI systems that efficiently uncover insights from compelling business interaction data – an exciting and unique opportunity within the industry.

This is an applied machine learning position with a strong emphasis on engineering, rather than research. You will play a key role in advancing our ML Engineering capabilities, particularly in information retrieval and eventually recommendation systems.

What you’ll be doing

• Own the full ML lifecycle: Take projects from ideation to production, including feature engineering, model selection, deployment, and model observability and evaluation.
• Translate business needs into ML solutions: Gather product requirements and translate them into robust ML system design requirements.
• Build recommendation and ranking systems: Architect and launch ranking and recommendation infrastructure from scratch, initially via integrated off-the-shelf models, and evolving to targeted and customized solutions in the long term.
• Solve complex problems: Work on a variety of information extraction, information storage and information retrieval problems for both structured and unstructured data.
• Collaborate cross-functionally: Partner with cross-functional (product, infra, data engineering, and software engineering) teams to build robust, high-scale systems that underlie all of our data processing and ML Operations.

Qualifications

Don’t meet every single requirement? Studies have shown that women and people of color are less likely to apply to jobs unless they meet every qualification. At Affinity, we are dedicated to building a diverse, inclusive, and authentic workplace, so if you’re excited about this role, but your past experience doesn’t perfectly align with the qualifications above, we encourage you to apply anyways. You may be just the right candidate for this or other roles.

Required

• 5+ years of experience in software engineering and/or Machine Learning experience in applying machine learning in production.
• Hands‑on experience developing ranking or recommendation systems from scratch, deployed at scale using techniques such as learn‑to‑rank, explainable recommendations.
• Strong understanding of machine learning techniques, including clustering and decision trees.
• Experience with serving ML models for streaming and batch inference at scale.
• Experience with vector or graph databases.
• Proficiency in Python and modern ML frameworks (PyTorch, Scikit-learn, or similar).
• Track record of building maintainable, testable, and production‑grade codebases.
• Experience with observability tools for online and offline model evaluation, A/B testing, and tracing for AI applications.

Nice to Have

• Experience with dataset engineering, including data curation, augmentation, and synthesis, to assist ML model improvement.
• Experience with graph‑based recommendation systems, such as graph NN.
• Experience with packaging, CI/CD, and pipeline automation.

Tech stack

Our ML pipeline manages multiple Python services that support various AI features, including utilizing OCR to extract information from unstructured data, serving embedding models to vectorize chunks, and ranking a list of recommendations based on relevance and user preference.

How we work

Our culture is a key part of how we operate, as well as our hiring process:

• We iterate quickly. As such, you must be comfortable embracing ambiguity, be able to cut through it, and deliver value to our customers.
• We are candid, transparent, and speak our minds while simultaneously caring personally with each person we interact with.
• We make data‑driven decisions and make the best decision for the moment based on the information available.

If you’d like to learn more about our values, click here.

Work Location: San Francisco, New York, or US Remote (Affinity is registered to employ in certain U.S. states)

For those located in San Francisco or New York, for this role we're embracing a hub‑hybrid model, designed to balance flexibility with meaningful in‑person collaboration. Team members within commuting distance are expected in‑office 2–3 days per week, typically Tuesday through Thursday. We believe great things happen when people come together intentionally to connect, create, and build momentum as a team.

What you'll enjoy at Affinity

• We live our values: As owners, we take pride in everything we do. We embrace a growth mindset, engage in respectful candor, act as playmakers, and "taste the soup" by diving deep into experiences to create the best outcomes for our colleagues and clients.
• Health Benefits: We cover your medical, dental, and vision insurance premiums with comprehensive PPO, HDHP and HMO options (in CA), and offer flexible personal & sick days to support your well‑being.
• Retirement Planning: We offer a 401(k) plan to help you plan for your future.
• Learning & Development: We provide an annual education budget and a comprehensive L&D program.
• Wellness Support: We reimburse monthly for things like home internet, meals, and wellness memberships/equipment to support your overall health and happiness.
• Team Connection: Virtual team‑building activities and socials to keep our team connected, because building strong relationships is key to success.

Please note that the role compensation details below reflect the base salary only and do not include any equity or benefits. This represents the salary range that Affinity believes, in good faith, at the time of this posting, that it will pay for the posted job.

A reasonable estimate of the current range is $160,000 to $235,000 USD. Within the range, individual pay depends on various factors including geographic location and review of experience, knowledge, skills, abilities of the applicant.

About Affinity

With more than 3,000 customers worldwide and backed by some of Silicon Valley's best firms, Affinity has raised $120M to empower dealmakers to find, manage, and close more deals. How? Our Relationship Intelligence platform uses the wealth of data exhaust from trillions of interactions between Investment Bankers, Venture Capitalists, Consultants, and other strategic dealmakers to deliver automated relationship insights that drive over 450,000 deals every month. We are proud to have received Inc. and Fortune Best Workplaces awards as well as to be Great Places to Work certified for the last 5 years running. Join us on our mission to make it possible for anyone to cultivate and fully harness their network to succeed.