MailerLite seeks a Machine Learning Engineer to build and ship predictive models on large-scale behavioral data and fine-tune LLMs to power a goal-driven assistant. Responsibilities include data preparation, training and inference pipelines, evaluation harnesses, and production serving. Requires 3+ years of production ML experience, hands-on LLM fine-tuning, strong Python and modern ML stack skills, and at least 4 hours overlap with CET. Remote-first role with advertised annual salary range €55k–€80k.

Remote role (Poland, Romania, Hungary, Serbia, Lithuania) as Associate Director, Data Engineering (Platform and Analytics). Responsible for lake house strategy (medallion architecture), engineering across ingestion, transformation, storage and optimization, ensuring data quality, security and lifecycle management. Leads and mentors global data engineering teams, champions cloud engineering and tools (notably Azure Databricks), and collaborates with Data & Technology and business stakeholders to enable analytics, AI readiness and sponsor data delivery. Bachelor's in CS/Information Systems (or equivalent experience) required; Master’s preferred. Experience expectations include enterprise cloud data initiatives, medallion architecture implementations, advanced SQL and Python, CI/CD, Power BI (preferred), and familiarity with GxP in life sciences.

Responsible for designing, building and supporting large-scale AI/HPC infrastructure with emphasis on networking (InfiniBand, EVPN/BGP/OSPF/VXLAN), switch/router platforms (Cumulus Linux, SONiC, IOS, JunosOS, EOS), automation (Ansible, Salt, Python), CI/CD, and monitoring. Requires BS/MS/PhD or equivalent and at least 8 years' professional networking experience. Strong English communication and customer focus required. Poland-specific annual salary ranges are provided in the posting.

Cast AI is hiring a Europe-remote Product Manager to own product areas end-to-end for a cloud-native, Kubernetes-powered platform. Candidates must have proven B2B product experience, strong Kubernetes knowledge (CKA preferred/required within 6 months), experience using AI/LLMs in product work, and enterprise customer engagement skills. Role accepts applicants residing in specified European countries. Cast AI does not provide visa sponsorship.

Wikimedia Foundation is hiring a Senior Site Reliability Engineer for Wikimedia Enterprise to design, develop, and maintain reliable, scalable infrastructure for high-volume API services. Responsibilities include defining SLOs/SLIs, building observability, running Kubernetes and cloud infrastructure, implementing CI/CD/GitOps (e.g., GitLab, ArgoCD), incident response and on-call duties, and collaborating with distributed teams. Strong SRE, cloud, IaC, observability, and automation skills are required.

Join Wikimedia Foundation as a remote Senior Site Reliability Engineer focused on data persistence. Responsibilities include operating and automating public-facing infrastructure (deployment, configuration, troubleshooting), using tools like Puppet and Kubernetes, collaborating with product teams, participating in a 24/7 on-call rotation and incident response, and mentoring peers. Requires 6+ years SRE/Operations/DevOps experience and strong English; preferred experience includes Prometheus/Grafana, Ceph/OpenStack Swift, distributed storage/databases, and LAMP technologies.

Time & material freelance role designing and shipping firmware for connected devices (wearables, audio, health-tech). Requires 4+ years professional firmware development, strong C/C++, hands-on ESP32 (ESP-IDF/ADF) and STM32 experience, BLE and IoT protocol knowledge, and English at B2+. Fully remote, flexible hours; potential path to permanent contract after an initial freelance period.

Freelance Senior Android Developer role working remotely (Warsaw-based office optional). Responsibilities include designing, building and maintaining Android apps that communicate with hardware over BLE, writing Kotlin, using Jetpack Compose, applying unit testing/TDD, reviewing code, and using AI tools in the workflow. Initial freelance/time & material engagement (paid by hours); potential path to permanent contract and benefits after ~3 months. English (B2+) required.

Freelance Senior Flutter Developer to deliver cross-platform Flutter apps that interact with firmware and physical devices via BLE (experience with flutter_blue_plus preferred). Fully remote (Warsaw office & Gdansk cowork optional), paid on B2B hourly basis (90–180 PLN/h). Path to permanent contract possible after initial 3 months. Role requires commercial Flutter and Dart experience, platform debugging (iOS/Android), and strong problem-solving and collaboration skills.

Freelance Senior iOS Developer role (fully remote, Warsaw office available). Paid hourly B2B (90–180 PLN/h). Responsibilities: build and maintain iOS apps communicating with BLE hardware, write unit tests (XCTest/Quick/Nimble) with a TDD mindset, maintain CI/CD (GitHub Actions/Bitrise/Travis), review PRs, and collaborate with firmware, design, QA, and PMs. Path to permanent contract possible after initial 3 months.

Senior backend engineer (freelance, T&M) to own end-to-end backend architecture for IoT/connected-device projects: data ingestion, APIs, cloud infra on AWS (EKS, Aurora, DynamoDB, Timestream, S3), Kubernetes, Docker, Terraform, MQTT and CI/CD. Requires 7+ years backend experience, strong Node.js in production, deep AWS and infra experience, English B2+. Fully remote with optional Warsaw office/coworking in Gdansk. Initial freelance period may lead to a permanent contract.

Join as a freelance Mobile Developer owning the mobile side of connected-product projects (wearables, sensors, health-tech). Design and implement robust BLE communication flows, debug device interactions, and work alongside firmware, backend, design, QA and PMs. Role is fully remote (optional Warsaw/Gdansk offices), paid 90–180 PLN/h B2B, with a path to a permanent contract after a successful initial 3-month period. Recruitment and day-to-day work in English (B2+).

Lead and mentor engineers to plan, schedule, and execute projects to create, optimize, and deploy training and inference deep learning workloads. Coordinate across teams and geographies, work on optimized numerical and DL algorithms, interact with scientific teams, and occasionally travel to conferences or customers. Minimum BSc and 8 years related experience (including 3 years management).

Lead the Data Science functional team to set multi-team roadmaps, provide hands-on mentorship, and guide projects involving statistical modeling, experiment design, classifier implementation, ML/NLP and LLM work. Requires 10+ years in data science or ML engineering (including 4+ years leading teams), production-grade Python and SQL skills, familiarity with columnar databases (BigQuery, ClickHouse, Redshift, Druid), and experience designing experiments and privacy-aware analytics. Position is remote (locations listed), expects ~40 hours/week, and requires travel ~2x/year. Compensation listed at $243,800 USD annually plus stock options.

Lead a distributed engineering team responsible for Kraken Pro's trading interface. Own technical direction, frontend architecture and delivery, partner with Product and Design, mentor engineers, and drive improvements in performance, accessibility, and reliability. Requires 8+ years software engineering experience and 3+ years leading engineers; deep experience with TypeScript and React (including React Native) is expected.

Lead the technical roadmap and manage a distributed engineering team for Wikimedia Enterprise, focusing on architecting, building, and maintaining high-volume data ingestion and B2B services. Responsibilities include team development and coaching, owning technical decisions, collaborating on product strategy, hiring, budgeting, and ensuring reliability/SLA delivery. Technologies mentioned include AWS, Kafka, Node.js, Go, PHP, Kubernetes/ECS and observability tooling.

Kraken is hiring a Staff React Native Engineer to own the technical vision and architecture of the Kraken Pro mobile app, working with React Native and TypeScript to improve performance, reliability, and scalability. The role requires 8+ years of software engineering experience, deep mobile expertise (iOS/Android), and experience leading or mentoring engineers across teams. Hiring is open in the countries listed in the posting.

Role owns full lifecycle of GPU compute clusters (procurement, provisioning, config management, monitoring, deprecation) across heterogeneous Linux environments. Requires 5+ years administering large-scale HPC/ML clusters, strong Linux and scripting skills, experience with Slurm, Ansible, storage solutions (NFS/Lustre/WekaFS), container runtimes, and high-speed networking technologies.

Join a senior team of DBAs, SREs, and platform engineers to scale PostgreSQL and vector search infrastructure, strengthen HA/DR and backup practices, build automation and GitOps workflows, improve observability and security, and collaborate with service and AI teams. Requires 5+ years operating PostgreSQL in high-volume production environments.

Primer seeks a senior Product Ops Lead to own the operating model for the full product organisation (planning cadences, roadmap governance, OKR cycles), define how product performance is measured (instrumentation and dashboards), set product tooling strategy, lead go-to-market readiness across functions, resolve systemic friction, and build documentation/onboarding/decision-records. Substantial senior Product Operations or equivalent experience, strong analytical capability (working with data and dashboards), cross-functional influence, and multi-quarter strategic thinking are required. Remote, distributed role with hiring markets in the listed countries.