10/14/2026 updated
100 % available
Senior Backend, Platform and Automation Engineer
Krosno, Poland
Only remote
Backend Development
Expertise in building backend systems using Go, Python, TypeScript and Node.js, including REST APIs, API integrations, and multi-tenant architectures with tenant isolation at the PostgreSQL row level.
Infrastructure and DevOps
Proficiency with Kubernetes, Hetzner, Linux, NetBird, Docker, NixOS, Git, OpenTelemetry, and self-hosting and management of 10+ servers.
AI Agent Development
Building agentic development workflows using LLM agents, MCP, Temporal Go SDK, human approval workflows, and AI output verification for production software platforms.
Data and Messaging
Working with PostgreSQL, Redis, SQLite, S3-compatible storage, row-level security, queued jobs, retry and backoff mechanisms.
Mobile Development
Building iOS and Android mobile apps using Flutter, Riverpod, go_router, with Firebase push notifications, Patrol end-to-end tests, and Fastlane for automated releases.
Workflow Automation
Designing and implementing automated workflows using Temporal, including release trains, CI/CD pipelines, health probes, migrations, and rollback strategies.
E-commerce and Marketplace Integrations
Building operations platforms with synchronization of products, prices, stock and orders through BaseLinker APIs, integrating with Allegro, Amazon, eBay, Temu, Erli, and Joom.
Payment and Billing Systems
Implementing billing layers with provider plug-ins, idempotent payment processing, amount validation, state machines, refunds, and status handling.
Trading and Real-time Data Systems
Designing 24/7 automated systems for exchange integrations, trading bots, real-time market data processing, monitoring, and alerting.
Expertise in building backend systems using Go, Python, TypeScript and Node.js, including REST APIs, API integrations, and multi-tenant architectures with tenant isolation at the PostgreSQL row level.
Infrastructure and DevOps
Proficiency with Kubernetes, Hetzner, Linux, NetBird, Docker, NixOS, Git, OpenTelemetry, and self-hosting and management of 10+ servers.
AI Agent Development
Building agentic development workflows using LLM agents, MCP, Temporal Go SDK, human approval workflows, and AI output verification for production software platforms.
Data and Messaging
Working with PostgreSQL, Redis, SQLite, S3-compatible storage, row-level security, queued jobs, retry and backoff mechanisms.
Mobile Development
Building iOS and Android mobile apps using Flutter, Riverpod, go_router, with Firebase push notifications, Patrol end-to-end tests, and Fastlane for automated releases.
Workflow Automation
Designing and implementing automated workflows using Temporal, including release trains, CI/CD pipelines, health probes, migrations, and rollback strategies.
E-commerce and Marketplace Integrations
Building operations platforms with synchronization of products, prices, stock and orders through BaseLinker APIs, integrating with Allegro, Amazon, eBay, Temu, Erli, and Joom.
Payment and Billing Systems
Implementing billing layers with provider plug-ins, idempotent payment processing, amount validation, state machines, refunds, and status handling.
Trading and Real-time Data Systems
Designing 24/7 automated systems for exchange integrations, trading bots, real-time market data processing, monitoring, and alerting.
Experience
Professional experience10+ years
Freelancer since2012
Languages
EnglishFluentPolishNative speaker
Project history
Developer tooling and AI automation. Internal platform for AI agent development and the production workflow used to build and release software platforms. Builds the Go kernel of an agentic development harness that orchestrates LLM coding and review agents. Implements workflows that write, gate, verify and ship pull requests, with hundreds of test files and daily execution. Provides concurrency primitives, Temporal Go SDK workflows, an MCP server and a Bubble Tea terminal interface.
AI SaaS and automated website development. Platform in development where AI agents build client websites through long-running workflows, human approval steps and checked AI output. Designed long-running Temporal workflows for AI agent execution, human approval and output checks before publication. Built a billing layer with provider plug-ins behind one contract for checkout or transfer, notification verification, refunds and status handling. Implemented idempotent payment processing, amount validation and an awaiting to paid to refunded state machine that refuses invalid transitions. Connected paid orders to Temporal fulfilment workflows with retry, backoff and skipping of completed steps on rerun.
Booking software and barber services. Multi-tenant booking platform where each business has isolated staff, services, calendars and client-facing portals. Designed and built the backend with tenant isolation at the PostgreSQL row level, authentication, storage, workers and 209 API routes. Built customer and barber mobile apps for iOS and Android with live booking and calendar updates, push notifications, tenant-tagged crash reporting and navigation reporting. Designed an automated release train using Temporal workflows, Mac build workers, Fastlane and Patrol end-to-end tests, with pinned images, migrations, health probes and rollback. The platform is built and released through an agentic development workflow that writes, gates, verifies and ships pull requests daily.