Senior Backend Engineer at HumanSignal

<div class="content-intro"><h2><strong>About HumanSignal</strong></h2> <p>Real-world data is the competitive edge in AI.</p> <p>HumanSignal is a human data partner for companies building AI models and products. Our customers ship better AI, faster, because we partner with their researchers from real-world data creation to annotation to delivery.</p> <p><br>We design and create datasets from scratch, recruit and manage the domain experts who evaluate model output, and run everything through our own platform, Label Studio, the open-source standard for data labeling and evaluation, used by over 1 million practitioners worldwide.</p> <p><br>We specialize in the operationally complex: real-world data collection, multimodal pipelines, and multi-step workflows. Advanced ML and AI teams use our enterprise platform to run their own data factories, and our services team to extend their reach where in-house capacity runs out.</p> <p><br>If you want to do work that materially shapes how the next generation of AI products gets built, we'd love to talk.</p></div><p style="text-align: center;"><span style="font-size: 12pt;"><strong>This is a product-engineering role:</strong> not “build what you’re told,” but <strong>shape what we build</strong>—own the problem, propose solutions, and ship outcomes that matter to users and the business.</span></p> <h1 style="text-align: left;"><strong>About the role</strong></h1> <p>We’re hiring a <strong>Senior Backend Engineer with product vision</strong>. You’ll design and operate services in <strong>Python/Django</strong> that power labeling and <strong>evaluation</strong> 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 <strong>simple</strong>, <strong>reliable</strong>, and <strong>fast</strong> for users.</p> <h2><strong>Responsibilities</strong></h2> <ul> <li>Design, build, and operate backend services/APIs in <strong>Python/Django</strong> with <strong>Postgres/Redis</strong>.</li> <li><strong>Own outcomes, not tasks:</strong> refine scope, suggest trade-offs, and land increments that deliver value quickly and safely.</li> <li>Model data and author migrations; tune queries and caching; manage <strong>background jobs/queues</strong> for high-volume workflows.</li> <li>Evolve API contracts with FE; keep interfaces clear, versioned, and resilient to change.</li> <li>Improve reliability and performance (timeouts, retries, idempotency, rate limits, pagination, backpressure).</li> <li>Implement secure, multi-tenant patterns: auth, permissions/RBAC, auditability, and safe data boundaries.</li> <li>Contribute to testing strategy (unit/integration), error handling, and graceful failure modes.</li> <li>Partner with <strong>Support</strong> to investigate production issues and turn learnings into fixes and prevention.</li> <li>Engage with our <strong>open-source community</strong> (issues, discussions) to understand real-world needs and improve developer experience.</li> <li>Participate in architecture discussions and code reviews; mentor teammates and improve patterns across the codebase.<br><br></li> </ul> <h2><strong>What you’ll bring</strong></h2> <ul> <li>Senior-level experience shipping production backends in <strong>Python/Django</strong> (or a close equivalent) and <strong>SQL</strong>.</li> <li>Strong <strong>product sense</strong>: you’ve made scope/trade-off decisions and iterated based on real-world usage and feedback.</li> <li>Depth in REST API design, relational modeling, migrations, and performance tuning.</li> <li>Experience with <strong>background processing/queues</strong> (e.g., Celery/RQ/Kafka-backed workers) and operational concerns.</li> <li>Clear written communication at a Senior IC level—concise RFCs/PRDs, actionable reviews, and crisp decision records.</li> <li><strong>Nice to have:</strong> GraphQL familiarity; Kafka/streaming; Spark/BigQuery; security/compliance exposure; multi-region architectures.<br><br></li> </ul> <h2><strong>Our stack</strong></h2> <p>Python/Django, JS/TS, React, OpenAI API, Spark, BigQuery, Kafka, Jest, Cypress, AWS, Kubernetes, Postgres, Redis.</p> <h2><strong>How we build</strong></h2> <p>Trunk-based development with small, reviewable PRs; feature flags for safe rollouts; strong code reviews; pragmatic testing; and close collaboration with Product/Design/Support.</p> <h2><strong>How we work</strong><strong><br></strong></h2> <p>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.</p> <p>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 tasks that never quite fit into regular sprints but really help us feel good about our codebase and workflows.</p> <h2><strong>Location &amp; Compensation</strong></h2> <p>At HumanSignal we pay based on regional compensation market rate ranges across the globe. We are hiring for this role across North and South America as well as Europe. The base cash compensation range is $140,000 to $200,000 USD. These ranges are provided by market data and are in good faith. The final offer details are determined by several factors including candidate experience, expertise, as well as applicable industry knowledge and may vary from the pay ranges listed above.</p> <p><strong>It’s an exciting time at HumanSignal.</strong> We’re growing quickly, and roles evolve as we learn. We’ve put thought into your first initiatives, but we’ll refine them together. If this sounds exciting, come build with us.</p>