Senior Backend Engineer

About the Company

HumanSignal is a human data partner for companies building AI models and products. We design and create datasets from scratch, recruit and manage domain experts, and run everything through our own platform, Label Studio, the open-source standard for data labeling and evaluation.

Responsibilities

• Design, build, and operate backend services/APIs in Python/Django with Postgres/Redis
• Own outcomes by refining scope and suggesting trade-offs
• Model data, author migrations, tune queries, and manage background jobs/queues
• Evolve API contracts with frontend teams to keep interfaces clear and resilient
• Improve reliability and performance including timeouts, retries, and rate limits
• Implement secure, multi-tenant patterns such as RBAC and auditability
• Contribute to testing strategy, error handling, and graceful failure modes
• Partner with Support to investigate and fix production issues
• Engage with the open-source community to understand real-world needs
• Participate in architecture discussions, code reviews, and mentor teammates

Requirements

• Senior-level experience shipping production backends in Python/Django and SQL
• Strong product sense and experience making scope/trade-off decisions
• Depth in REST API design, relational modeling, and performance tuning
• Experience with background processing and queues (e.g., Celery, RQ, or Kafka)
• Clear written communication for RFCs, PRDs, and decision records

Preferred Qualifications

• GraphQL familiarity
• Kafka or streaming experience
• Spark or BigQuery experience
• Security/compliance exposure
• Multi-region architecture experience