Senior Data Engineer / Data Architect – Azure Data Explorer, IoT streaming (Freelance)

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Currently we are looking for a Senior Data Engineer with architect skills to join an environmental monitoring platform for industry. You'll take over a working proof of concept of a streaming IoT measurement pipeline on Azure and bring it to production – from edge devices, through the raw layer, to read-optimised data and rollups in Azure Data Explorer.

Location: Remote/Warsaw Office
Salary (PLN): 160-200 net + VAT (B2B)
Start: November

What will you do?
• Take over the PoC and bring it to production – the data semantics are already defined, so you can focus on the pipeline.
• Build the stream processor from Event Hubs to Azure Data Explorer.
• Design and schedule the cascade of rollups and time-window aggregations.
• Implement reprocessing of data after configuration changes.
• Model and optimise ADX tables, update policies, materialized views, retention policies and queries for large data volumes.
• Work closely with our PM, our ADX specialist, the client's engineering team and our DevOps.

What we're looking for:

Must-have:
• At least 2–3 data pipeline projects taken from zero to production in the role of architect or lead data engineer, with Azure Data Explorer in production in at least one of them.

Experience:
• Senior experience in data engineering (around 5+ years), including IoT streams and time-series data
• Broad, hands-on experience with Azure data services

Tech skills:
• Azure Data Explorer (Kusto) and KQL: table modelling, update policies, materialized views, retention policies, query optimisation for large volumes
• Streaming ingestion on Azure: IoT Hub, Event Hubs, parsing functions (e.g. Azure Functions), Blob Storage
• Layered data architecture (raw/Bronze → Silver → aggregates), designing rollups and time-window aggregations
• Python
• Terraform

Soft skills:
• Independence – you can own a production pipeline end to end without hand-holding
• At least B2 in English – we work internationally, so that's a must
• Strong collaboration and communication skills – you'll work with several teams
• Attention to detail

Nice-to-haves:
• Environmental data (spectra, multi-parameter data, interval and event data)
• Preparing data for ML (e.g. anomaly detection) and near-real-time queries
• PostgreSQL/PostGIS and spatial data
• Edge devices / edge computing
• TypeScript/NestJS

How to apply
Along with your CV, please send a short description of 2–3 data pipelines you took to production. For each one: your role, scope, stack, data scale, what went wrong and what you would do differently – plus a link or reference if possible.
Note: Please keep in mind that this is a part-time, freelance opening.