Senior Backend Engineer

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HumanSignal is building the platform that powers the creation, curation, and evaluation of high‑quality data for AI. Our open‑source product, Label Studio, is the de‑facto standard for labeling and evaluating data across modalities. This product‑engineering role will shape what we build, build the services that power labeling and evaluation workflows at scale, and deliver reliable, fast APIs and backend systems.

About the role

Senior Backend Engineer with product vision. 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. Partner early with PM, Design, or FE to frame problems, prototype, and ship outcomes that matter to users and the business.

Responsibilities

• Design, build, and operate backend services/APIs in Python/Django with Postgres/Redis.
• Own outcomes: refine scope, suggest trade‑offs, and land increments that deliver value quickly and safely.
• Model data, author migrations, tune queries and caching, and manage background jobs and queues for high‑volume workflows.
• 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 close equivalent) and SQL.
• Strong product sense: experience making scope and trade‑off decisions and iterating 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, and decision records.
• Nice to have: GraphQL familiarity; Kafka/streaming; Spark/BigQuery; security/compliance exposure; multi‑region architectures.

Our stack

Python/Django, JavaScript/TypeScript, 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, and Support.

Location & compensation

HumanSignal pays based on regional compensation market rate ranges across the globe. Base cash compensation range is $140,000 to $200,000 USD.