# Senior AI Engineer, Post-Training at Carta

- Company: Carta
- What the company does: Carta’s ERP for private capital combines software and services to deliver connected clarity and control across equity, fund, and portfolio management. Backed by Lightspeed and a16z.
- Company website: https://carta.com/
- Type: Startups (AI role)
- Level: Senior
- Location: San Francisco, CA; New York City, NY
- Work setup: On-site
- Pay: $242K to $285K base salary per year (USD)
- Posted: 2026-09-21
- Apply by: 2026-11-05
- Apply: https://job-boards.greenhouse.io/carta/jobs/7992629003
- Page: https://www.1752.vc/careers/jobs/carta-senior-ai-engineer-post-training/

## About the role

You’ll join Carta’s ML Engineering team, embedded in Carta Law, our legal tech platform built around autonomous AI agents, specialized legal models, document intelligence and contract workflows. You’ll have end-to-end ownership across model development and applied AI, from post-training and evaluation through model serving and the agents and systems built around those models. You'll work closely with the engineers building the product and bringing these capabilities to users.

## What they're looking for

- Post-train open-weight language models on proprietary legal data, owning the model development lifecycle end-to-end, from data, objective design, and base-model selection through training, evaluation, and iteration
- 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 needed to run experiments reliably, using managed or self-hosted infrastructure as appropriate, and understand distributed training well enough to diagnose and optimize training runs
- Build and operate the systems that take models into production, including model serving, agents, evaluation pipelines, and the surrounding tooling and infrastructure
- Partner with product and agent engineers on model/system co-design, deciding what belongs in the model versus the agent harness, tools, context, and workflow
- Work directly with lawyers and other domain experts to translate real workflows into model, data, and evaluation decisions

Tags: Data & Machine Learning