Senior Backend Engineer, Customer Data Platform

Piano is a global technology company providing a Digital Experience Cloud that helps organizations understand and influence customer behavior through unifying customer data, behavior analytics, and personalized customer journeys. The Customer Data Platform team, headquartered in Kyiv with an office in Warsaw, develops services mainly using Node.js and TypeScript, including event pipelines, Elasticsearch query layers, background processing, and sandboxed customer logic execution. Piano serves notable clients across multiple continents and has been recognized for innovation and growth.

• Daily, fluent practice with Claude Code on production code and discernment in agent trust.
• Strong expertise in Node.js and TypeScript with ESM, strict tsconfig, and testing using Jest/Mocha.
• Deep knowledge of Elasticsearch 8.x including mappings, reindexing, sorting, range semantics, deep pagination, and backpressure.
• Experience with Kafka at scale covering partitioning, consumer concurrency and lag, dead-letter handling, and topic lifecycle.
• Habitual production ownership including on-call responsibility, root cause analysis, Datadog instrumentation, toggle-gated rollouts, and profiling.
• Proficiency with PostgreSQL using an ORM, including migrations, indexing, and transaction semantics.
• Willingness to manage Kubernetes, Helm, GitOps, and GitLab CI, as well as dependency and CVE triage.
• Clear technical English communication skills for collaboration with product and business stakeholders.

Nice to have:

• Experience building MCP servers, agent skills, or tooling enhancing agent coding.
• Knowledge of efficient JavaScript execution environments like V8 isolates.
• Familiarity with ClickHouse, Aerospike, ArangoDB, and Redis.
• Experience with gRPC, Testcontainers, WireMock, and stabilizing time-dependent tests.
• Use of large-repository tools such as Rush and pnpm workspaces.
• Experience with high-volume, multi-tenant data platforms.
• Maintenance experience in Java end-to-end test suites.

• Deliver code through Claude Code, improving context, tooling, and evaluation of agent output.
• Own event-pipeline services, handling load spikes, backpressure, retries, and dead lettering.
• Manage Elasticsearch query and search layers, including deep pagination and memory/rate limit behavior.
• Own sandboxed execution of customer logic and integrations with other Piano products and third-party systems including API contracts.
• Lead integration efforts across teams, negotiating technical contracts and coordinating rollouts.
• Scope epics and trade-offs with technical, product, and business stakeholders and produce decision records.
• Perform comprehensive code reviews scaled to risk and ensure test determinism.
• Conduct production changes end to end using Helm and FluxCD GitOps.
• Participate in recurring on-duty rotations for alert triage, hotfixes, and customer communications.

Applicants must be authorized to work in Poland without sponsorship from Piano. Piano is an equal opportunity employer.