This is a product-engineering role: not “build what you’re told,” but shape what we build—own the problem, propose solutions, and ship outcomes that matter to users and the business.

About the role

We’re hiring a Senior Backend Engineer with product vision. You’ll design and operate services in Python/Django that power labeling and evaluation workflows at scale: clean API contracts, robust data models, efficient background jobs, and dependable performance. You’ll partner early with PM/Design/FE to frame problems, prototype to learn, and make pragmatic scope calls—so complex workflows feel simple, reliable, and fast for users.

Responsibilities

• Design, build, and operate backend services/APIs in Python/Django with Postgres/Redis.
• Own outcomes, not tasks: refine scope, suggest trade-offs, and land increments that deliver value quickly and safely.
• Model data and author migrations; tune queries and caching; manage background jobs/queues for high-volume workflows.
• Evolve API contracts with FE; keep interfaces clear, versioned, and resilient to change.
• Improve reliability and performance (timeouts, retries, idempotency, rate limits, pagination, backpressure).
• Implement secure, multi-tenant patterns: auth, permissions/RBAC, auditability, and safe data boundaries.
• Contribute to testing strategy (unit/integration), error handling, and graceful failure modes.
• Partner with Support to investigate production issues and turn learnings into fixes and prevention.
• Engage with our open-source community (issues, discussions) to understand real-world needs and improve developer experience.
• Participate in architecture discussions and code reviews; mentor teammates and improve patterns across the codebase.
  
  

What you’ll bring

• Senior-level experience shipping production backends in Python/Django (or a close equivalent) and SQL.
• Strong product sense: you’ve made scope/trade-off decisions and iterated based on real-world usage and feedback.
• Depth in REST API design, relational modeling, migrations, and performance tuning.
• Experience with background processing/queues (e.g., Celery/RQ/Kafka-backed workers) and operational concerns.
• Clear written communication at a Senior IC level—concise RFCs/PRDs, actionable reviews, and crisp decision records.
• Nice to have: GraphQL familiarity; Kafka/streaming; Spark/BigQuery; security/compliance exposure; multi-region architectures.
  
  

Our stack

Python/Django, JS/TS, React, OpenAI API, Spark, BigQuery, Kafka, Jest, Cypress, AWS, Kubernetes, Postgres, Redis.

How we build

Trunk-based development with small, reviewable PRs; feature flags for safe rollouts; strong code reviews; pragmatic testing; and close collaboration with Product/Design/Support.

How we work

At HumanSignal, we follow a six-week cycle known as "Build and Ship" followed by a "Cooldown." During the first four weeks, the team focuses on creating new features and shipping improvements. We also rotate a small group to handle customer support, ensuring everyone stays in touch with real user needs and we can respond quickly to issues.

After those four weeks, we have a two-week "Cooldown" period. This is when we tackle technical debt, refine our integration processes, and wrap up those lingering ta