Senior AI Engineer, Post-Training

Carta
San Francisco, New York
Workplace: OnsiteFull timeUSD 242,250 - 285,000Function: Data Science & Machine LearningSkills: ["Technical judgment","Communication","Cross-functional collaboration","Execution","Problem solving"]

Own the full lifecycle of LLM post-training for Carta’s legal AI platform, from data and objective design through training, evaluation, iteration, and production serving. Lead model-centric projects using techniques like supervised fine-tuning, preference optimization, and reinforcement learning. Build training datasets, pipelines, and distributed training experiments, then co-design model/agent workflows with product and domain experts to ship capabilities to real users.

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FursaFursa
Carta
Carta
1 day ago

Senior AI Engineer, Post-Training

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Canonical indexed version, validated from employer's careers page.

Source: Company careers pageValidated by: Fursa AI
Last checked: 12 hours agoStatus: Live

Job Summary

Own the full lifecycle of LLM post-training for Carta’s legal AI platform, from data and objective design through training, evaluation, iteration, and production serving. Lead model-centric projects using techniques like supervised fine-tuning, preference optimization, and reinforcement learning. Build training datasets, pipelines, and distributed training experiments, then co-design model/agent workflows with product and domain experts to ship capabilities to real users.
Location: San Francisco, New York
Workplace: Onsite
Employment Type: Full time
Job Function: Data Science & Machine Learning
Seniority: Mid level

Key Responsibilities

  • •Post-train open-weight language models on proprietary legal data end-to-end, including data, objective design, base-model selection, training, evaluation, and iteration.
  • •Apply appropriate training techniques (supervised fine-tuning, preference optimization, reinforcement learning) with careful attention to reward/grader design and evaluation of model behavior.
  • •Build and improve training datasets and data pipelines, including labeling guidance, model-generated data, and human feedback loops with domain experts.
  • •Own the training stack for reliable experiments, using managed or self-hosted infrastructure as needed and diagnosing/optimizing distributed training runs.
  • •Build and operate systems to take models into production, including model serving, agent/evaluation pipelines, and surrounding tooling and infrastructure.

Pay and Benefits

Salary: USD 242,250 - 285,000
Equity and Bonus:Equity
Perks:Equity

Key Requirements

  • •Hands-on experience with LLM post-training using PyTorch or equivalent frameworks, including training, evaluation, and inference systems.
  • •Comfort building both model-centric solutions and the surrounding product/infrastructure (agents, tools, services, and production infrastructure).
  • •Owned model development or post-training work in applied settings with shipped AI systems that improved real user outcomes.
  • •Ability to turn ambiguous model or product problems into tractable technical work, making pragmatic trade-offs and driving projects to production.
  • •Strong judgment on model selection, data, training objectives, and evaluation—knowing when to use training versus improving agent/tools/context and defending decisions with data.
Experience:AIApplied research
Skills:Technical judgmentCommunicationCross-functional collaborationExecutionProblem solving
Languages:English
Tech Stack:PyTorchLLMsSupervised fine-tuningPreference optimizationReinforcement learningDistributed trainingModel servingEvaluation pipelines

Company Brief

Carta
Provides equity management, cap table software, and valuation services for private companies and investors. Carta streamlines ownership tracking, employee equity plans, and compliance for startups, venture-backed firms, and venture capital investors.
Industry: Fintech Infrastructure
Company Size: Enterprise (1,001+ employees)
Growth: Scaleup
Valuation: Unicorn (USD 1B+)
Funding: Series G
Headquarters: San Francisco, United States
Founded: 2012
WebsiteLinkedIn