Senior Software Engineer, Annotations

We Love AI Jobs; San Francisco (CA); On-site; USD 208,000 - 260,000; Full time

Job summary

Handshake, leading AI data operations, seeks a Senior Software Engineer to join the Annotations team in San Francisco. You will own full-stack features and drive production delivery for annotation tooling and workflows.

You will mentor engineers, shape engineering practices, and collaborate with product, design, data, and operations to deliver reliable software that improves task quality and customer outcomes. This high-ownership role thrives in a fast-paced environment.

Qualifications

• 6+ years of software engineering experience building and operating production systems.
• Strong proficiency in Python, Node.js, TypeScript, React, PostgreSQL, and backend APIs.
• Experience designing scalable, reliable software and making architectural tradeoffs.
• Track record of owning complex projects from ambiguity through delivery.
• Excellent communication and collaboration with technical and non-technical partners.
• Mentoring engineers and elevating team practices.
• Comfort in a fast-moving environment where priorities change quickly.

Responsibilities

• Build and scale operator tooling to manage annotation projects.
• Design workflows and quality-control systems to improve task accuracy and throughput.
• Lead projects from concept to production delivery, including rollout and monitoring.

Skills

Python

Node.js

TypeScript

React

PostgreSQL

backend APIs

distributed systems

testing

Job description

# Senior Software Engineer, AnnotationsHandshakeSan Francisco, CAFull-time$208,000 – $260,000 / yearUpload your resume once and Scout applies for youApply with ScoutShare this job:LinkedInXSave imageThe 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 expertisePythonNode.jsTypeScriptReactPostgreSQLbackend APIsdistributed systemstesting### 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 comparesCompared 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 descriptionAbout HandshakeHandshake 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 RoleWe’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/TypeScript, 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 reviews and architecture discussions, and help unblock the team.• Improve engineering processes, testing practices, observability, and operational health across the squad.You have• 6+ years of software engineering experience building and operating production systems.• Strong proficiency in Python, Node.js, Typescript, React, PostgreSQL, and backend APIs.• Experience designing scalable, reliable software and making sound architectural tradeoffs.• A track record of owning complex projects from ambiguity through delivery.• Strong product judgment and an ability to connect technical decisions to customer and business outcomes.• Excellent communication skills and the ability to work effectively with technical and non-technical partners.• A quality mindset: you write maintainable code, test thoughtfully, debug deeply, and address root causes.• A collaborative leadership style, including experience mentoring engineers and elevating team practices.• Comfort working in a high-velocity environment where priorities and requirements evolve quickly.Bonus points• Experience building workflow, marketplace, operations, or internal-platform software.• Familiarity with AI/ML data pipelines, annotation systems, evaluation workflows, or human-in-the-loop products.• Experience working with distributed teams, expert networks, or high-volume operational processes.