Senior Software Engineer, Annotations

# Senior Software Engineer, Annotations Handshake San  Francisco, CAFull-time $208,000 – $260,000 / year Upload your resume once and Scout applies for you Apply with Scout Share this job:

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The Senior Software Engineer builds annotation tools and quality-control workflows used to produce human data for frontier AI companies. The role owns full-stack projects from planning through production, while also setting technical direction and mentoring engineers.
* Permanent* On-site
* 6+ years### Skills and expertise

Python

Node.jsType Script React Postgre SQLbackend APIsdistributed systems testing### Key responsibilities
* Build and scale tools for creating, managing, prioritizing, and auditing annotation projects.
* Develop workflow and quality-control systems that improve task accuracy, throughput, and customer outcomes.
* Lead projects through production delivery, mentor engineers, and improve team engineering practices.## How this job compares

Compared with 1,635 open senior engineering jobs on October 10, 2026.Pay:
This job pays $208K to $260K a year. The 719 open senior engineering jobs that publish US pay start at $164K on average, so this job starts about 27% higher.

Similar open jobs:
We Love AI Jobs lists 1,635 open senior engineering jobs at 344 companies.

Remote work:
This job is on site. 271 of the 1,635 senior engineering jobs (17%) are remote.

AI in this role:
Medium. The role uses AI tools and works with AI systems as a regular part of the job. The role builds annotation software and workflows that provide human data to frontier AI companies. It supports AI data operations but does not directly build or train models.## Full description

About Handshake Handshake was founded on a simple belief that everyone deserves a path to a great career, regardless of where they went to school or who they know. Today, we power 25 million job seekers, 1 million+ employers, and 1,600 educational institutions.

About Handshake AIHuman data is the core infrastructure to AI advancement. Frontier AI labs currently improve model capabilities with various data-intensive post-training techniques. We believe that data spend for AI training will increase by 3-5x in the next few years and continue for much longer as models take on new domains. Handshake AI supports all of the frontier AI labs, working on their most complex data at the largest scale.

The Role We’re looking for a Senior Software Engineer to join our Annotations team and build the systems that power high-quality human data for frontier AI companies. You’ll work at the intersection of product engineering, distributed systems, and AI data operations—designing tools that help operators manage annotation projects, improve task quality, and scale expert workflows.

This is a high-ownership role in a fast-moving environment. You’ll partner closely with product, design, data, operations, and engineering teams to turn ambiguous problems into reliable, intuitive software used across the annotation lifecycle.

What you’ll do
• Build and scale operator tooling that enables teams to create, manage, prioritize, and audit annotation projects.
• Design workflows and quality-control systems that improve task accuracy, throughput, and customer outcomes.
• Develop performant full-stack features using Python, Node.js/Type Script, React, PostgreSQL, and backend APIs.
• Establish technical direction for complex projects, balancing speed, maintainability, reliability, and operational needs.
• Partner with product, design, operations, and data teams to define requirements and ship impactful solutions.
• Lead projects from initial concept through high-quality production delivery, including rollout, monitoring, and iteration.
• Mentor engineers, raise the quality of code…