We are seeking a Senior Python + Data Systems Engineer for a US-based SaaS company in marketing analytics.

Please note that the working hours for this position are until 11 PM Kyiv time.

About the Client
The client is an American SaaS company in marketing analytics. Its platform helps e-commerce brands understand which ad spend truly drives revenue. It collects tracking data, combines it with data from major ad platforms, and uses ML modeling to turn it into reporting.
The company’s customers spend millions per month on advertising, so data volumes are large and business decisions depend on data accuracy.

About the Project

There are several projects in progress

Conversion API (main project): reprocessing tracking signals and delivering them to ad-platform APIs in real time. Each platform’s API works differently and has its own quirks, so integrations require careful work. Stack: Python streaming, Google Pub/Sub, Shopify JS tracking.
Mobile attribution SDK (greenfield): a new SDK for JavaScript and iOS.
Analytics data pipelines: pipelines built as part of the SaaS product, not internal BI.
Full-stack product development: application features and integrations.

Requirements

7+ years of commercial experience with Python in production at Senior level.
Strong SQL skills. You are confident working with complex queries and large data volumes, as data accuracy directly drives clients’ business decisions
Hands-on experience building and maintaining integrations with third-party APIs
Experience with streaming or event-driven systems (message queues, pub/sub, real-time data processing), as the main project delivers tracking signals to ad platforms in real time
Experience with GCP and BigQuery
Track record of building customer-facing products, not just internal tools or dashboards
Experience with SaaS products used by external customers is a strong fit
Ability to design engineering abstractions and discuss architectural decisions with the team, explaining trade-offs
Fluent English (C1) for daily communication with the US team: syncs, technical discussions and written communication

Nice-to-have

Experience with Snowplow or OpenSnowcat
Experience with Conversion APIs
Background in marketing analytics and e-commerce
Experience with Google Pub/Sub and Airflow

Responsibilities

Work as a backend-heavy engineer on integrations, APIs, services and streaming pipelines
Develop the Conversion API: reprocess tracking signals and deliver them to ad-platform APIs in real time, handling the specifics of each platform’s API
Build analytics data pipelines as part of the SaaS product
Contribute to architecture discussions and engineering abstractions