Lead Data Scientist

Middesk
San Francisco, US
Hybrid

Who this role is best for

Aimed at senior ML experts who have shipped risk/fraud models and can mentor peers in a hybrid SF/NYC setting.

Best fit for

  • Senior ICs with production ML experience in fraud detection and entity resolution.
    — “5+ years of production ML experience in one or more of the following areas
  • Applied ML practitioners comfortable with extreme class imbalance and sparse signals.
    — “know the messy realities of imbalanced data, low labels, and changing behavior
  • Technical leaders who can establish ML infrastructure foundations while mentoring peers.
    — “Comfort as a senior IC: setting technical direction, mentoring peers, and establishing best practices

Things to consider

  • Hybrid model requires 2 days per week in SF/NYC offices.
    — “expectation of 2 days per week in our SF/NYC office
  • Must be commutable to SF/NYC for in-person collaboration.
    — “Candidates should be based within a commutable distance

How to stand out

  • Showcase specific examples of shipping external-facing risk/fraud models.
    — “Track record of shipping external-facing ML applications in one or more of these domains
  • Highlight hands-on experience with knowledge graphs for business identities.
    — “Hands-on experience building, querying, or extracting signals from knowledge graphs
  • Demonstrate innovations in feature engineering for imbalanced datasets.
    — “Innovate in feature engineering & labeling: Use graph-based techniques, weak supervision, LLMs, and AI agents
Pace · Fast PacedCollaboration · HighAutonomy · MediumDecision Impact · TeamLevel · Senior

Derived from job-description analysis by Serendipath's career intelligence engine.

What success looks like

  • Build risk & fraud ML applications
  • Tackle hard data problems
  • Establish ML infrastructure foundations
Typical background
5+ years of production ML experience in risk, fraud, credit, or trust & safety

Skills & requirements

Required

Risk And Fraud ML ApplicationsClassification Problems With Extreme Class ImbalanceFeature Engineering And LabelingML Infrastructure FoundationsKnowledge Graph SolutionsLlms For Graph Construction

Preferred

B2B Saas ExperienceML Pipeline And Automation Engineering

Stack & domain

Ml ApplicationsRisk/fraud SpaceImbalanced DataSparse SignalsCold StartFeature StoresModel ManagementMl Training/serving PipelinesGraph-based TechniquesWeak SupervisionLlmsAi AgentsKnowledge Graph SolutionsEntity ResolutionBusiness Identity VerificationFraud DetectionRisk DecisioningLeadershipCommunicationMentorshipAi-driven ApplicationsRisk/fraudMl InfrastructureKnowledge Graph

About the role

Original posting from Middesk via Ashby

ABOUT MIDDESK:

Middesk makes it easier for businesses to work together. Since 2018, we’ve been transforming business identity verification, replacing slow, manual processes with seamless access to complete, up-to-date data. Our platform helps companies across industries confidently verify business identities, onboard customers faster, and reduce risk at every stage of the customer lifecycle.

Middesk came out of Y Combinator, is backed by Sequoia Capital and Accel Partners, and was recently named to Forbes Fintech 50 List.

ABOUT THE ROLE:

We are actively building AI-driven applications that streamline customer workflows, focusing on business onboarding. With our proprietary identity data assets and deep domain expertise, we are uniquely positioned to expand into a broader set of AI-powered solutions that drive long-term growth.

We’re looking for a hands-on applied ML expert to help build the technical foundation for these efforts. Ideally you have shipped external-facing models in the risk/fraud space and know the messy realities of imbalanced data, low labels, and changing behavior. This is a highly technical, hands-on role with wide influence on how we design, build, and scale ML at Middesk.

We follow a hybrid work model, and for this role, there is an expectation of 2 days per week in our SF/NYC office. Candidates should be based within a commutable distance, as we believe in the value of in-person collaboration and building strong team connections while also supporting flexibility where possible.

WHAT YOU'LL DO:

  • Build risk & fraud ML applications: Deliver production ML models in fraud, trust & safety, KYB, and compliance domains, with measurable impact on customer workflows.
  • Tackle hard data problems: Work on classification problems with extreme class imbalance, sparse signals, and “cold start” label challenges.
  • Innovate in feature engineering & labeling: Use graph-based techniques, weak supervision, LLMs, and AI agents to improve signal extraction and automate labeling process.
  • Establish ML infrastructure foundations: Partner with the ML infra team to design feature services, model training pipeline, model serving standards, and orchestration to scale multiple ML use cases.
  • Design and implement knowledge graph solutions: Leveraging LLMs for graph construction, querying, and retrieval to enhance entity resolution and business identity use cases.

WHAT WE'RE LOOKING FOR:

  • 5+ years of production ML experience in one or more of the following areas:
  • Building Production ML for risk, fraud, credit, or trust & safety: Track record of shipping external-facing ML applications in one or more of these domains.
  • Knowledge graph applications: Hands-on experience building, querying, or extracting signals from knowledge graphs—ideally over business entity networks (companies, persons, addresses, relationships) to support identity verification, fraud detection, or risk decisioning.
  • Entity resolution for business or individual identities: Experience disambiguating and linking records across noisy, incomplete, or conflicting data sources—particularly in KYB, KYC, AML, or identity verification contexts where the same real-world entity may appear under different names, addresses, or tax IDs.
  • Expertise in classification with real-world ML challenges, for example: imbalanced labels, sparse signals, cold start, and production version management.
  • Hands-on ML infrastructure experience: feature stores, model management, ML training/serving pipelines.
  • Comfort as a senior IC: setting technical direction, mentoring peers, and establishing best practices.

NICE-TO HAVE:

  • B2B SaaS experience, ideally building ML products for enterprise customers.
  • ML pipeline and automation engineering: Experience building end-to-end training harnesses that automate feature engineering, data validation, and model training.
  • Experience scaling ML across multiple products or risk domains.

Source: Middesk careers (Ashby)

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