Backend Engineer

• Join a product team building payment infrastructure for merchants and partner platforms
• Own end-to-end payment flows in TypeScript/NestJS services, including authorization, capture, void, refund, dispute handling, and payout initiation and confirmation
• Build and maintain acquirer and processor integrations using clean internal abstractions
• Design embedded and hosted checkout experiences, including hosted fields, iframes, and tokenization, to minimize PCI scope
• Implement fee calculation and rate logic, including tiers, interchange-plus, flat structures, rounding rules, special rates, and edge cases
• Build reconciliation and settlement layers matching processor reports and settlement files against internal records
• Design event handling with idempotency keys, out-of-order and duplicate webhooks, retries with backoff, and state machines
• Integrate fraud, bank-account verification, and KYC providers and tune decisioning against real outcomes
• Handle ACH mechanics, including submission windows, returns, return codes, NOCs, and retry rules
• Maintain domain correctness, complete audit trails, and reconciliation evidence
• Act as the team's payments expert, advise product on rail capabilities, and review payment-adjacent code
• Collaborate daily with a US-based team with 4–6 hours of overlap with US Central Time

Senior Backend Engineer – Payments, Go, TypeScript, Node.js

• Build and evolve systems collecting and maintaining 400M+ creator profiles across Instagram, TikTok, and YouTube
• Keep billions of data points fresh for search, analytics, APIs, and customer-facing products
• Design resilient services handling third-party API instability, rate limits, provider outages, platform changes, and partial failures
• Improve collection coverage and freshness while controlling request, proxy, storage, and compute costs
• Own the full production lifecycle from problem definition and architecture through coding, review, release, monitoring, and iteration
• Build monitoring, observability, and operational safeguards to detect gaps and regressions
• Collaborate with Data Search, Data Insights, product teams, and company leadership
• Participate in system design, indexing dependency work, request-routing reviews, and data-quality improvements

Senior Backend Engineer, Data Core

• Design, develop, and continuously improve the overall IAM/IGA architecture
• Create technical solution concepts and define integration strategies for IAM/IGA ecosystems
• Ensure a coherent and scalable end-to-end architecture across all identity-related services and platforms
• Design interfaces and integration mechanisms between IAM/IGA solutions and connected enterprise applications
• Identify architectural risks, dependencies, technical constraints, and mitigation strategies
• Ensure architectural compliance with security policies, regulatory requirements, and industry standards, including ISO 27001, BSI IT-Grundschutz, NIS2, and KRITIS
• Collaborate with client-side architects, security experts, and technical teams to drive architectural decisions
• Provide technical leadership and architectural guidance throughout the entire solution lifecycle
• Support governance processes and ensure architectural consistency across the program
• Review solution designs and recommend improvements in line with security and compliance requirements

IAM Technical Architect, German

• Architect, implement, and maintain scalable architecture and RESTful APIs using Java and Spring
• Engineer reliable backend services to manage multi-step business logic, status lifecycles, and event-driven notifications
• Design secure interfaces connecting internal modules with external systems while adhering to healthcare data privacy principles
• Optimize relational database schemas and query performance
• Enforce software engineering best practices through code reviews, automated unit/integration testing, and technical mentoring

Senior Java Developer

• Join one of two AI initiatives: ChatCPI, an LLM-powered assistant for intelligent search and question answering over large technical documentation, or a Knowledge Graph Platform focused on structuring and connecting enterprise information for AI-driven use cases
• Design and implement LLM-based features and RAG pipelines from data ingestion to answer generation
• Build and optimize retrieval using vector embeddings and hybrid semantic and keyword search
• Process, clean, and structure source information to improve the accuracy and relevance of AI-generated output
• Evaluate model quality, experiment with new approaches, and bring proven solutions into production
• Work closely with the team to integrate AI components into the wider platform
• Own changes end-to-end, including design, implementation, testing, and deployment
• Work independently while proactively communicating blockers, scope questions, and technical trade-offs

Middle Python Developer, ML

• Own end-to-end data extraction workflows across complex websites
• Ensure complete coverage, accuracy, and reliable delivery of structured datasets
• Use available tools and custom workflows to accelerate data collection, validation, and task execution
• Extract data reliably from dynamic and interactive web sources, adapting to JavaScript-rendered content and changing site behavior
• Enforce data quality through validation checks, cross-source consistency controls, formatting specifications, and systematic verification
• Scale scraping operations for large datasets using efficient batching or parallelization
• Monitor failures and maintain stability against minor site structure changes
• Utilize tools such as Apify, OpenRouter, and other technologies

Senior Python Data Scraping Engineer – Freelance

• Own end-to-end data extraction workflows across complex websites
• Ensure complete coverage, accuracy, and reliable delivery of structured datasets
• Use available tools and custom workflows to accelerate data collection, validation, and task execution
• Extract data reliably from dynamic and interactive web sources, adapting to JavaScript-rendered content and changing site behavior
• Enforce data quality through validation checks, cross-source consistency controls, formatting specifications, and systematic verification
• Scale scraping operations for large datasets using efficient batching or parallelization
• Monitor failures and maintain stability against minor site structure changes
• Use tools such as Apify, OpenRouter, and other technologies alongside technical expertise and custom approaches

• Dołączenie do nowo powstającego zespołu odpowiedzialnego za platformę zarządzania cyklem życia rezerwacji
• Projektowanie i rozwój usług backendowych przetwarzających dane w dużej skali
• Podejmowanie decyzji dotyczących niezawodności, wydajności i kosztu rozwiązania
• Diagnozowanie problemów produkcyjnych i udział w analizie incydentów
• Prowadzenie code review i wspieranie rozwoju innych osób w zespole
• Współpraca z zespołami produktowymi, DevOps i Agile Coach
• Obsługa danych rezerwacyjnych oraz przepływu powiązanych danych i procesów biznesowych, w tym rozliczeń, raportowania, analityki, przygotowania danych dla AI i wykorzystania narzędzi sztucznej inteligencji

Backend Engineer – .NET

• Scrape various APIs on an industrial scale (TBs/day)
• Build backend services using Python for high-load, data-intensive systems
• Optimize data pipelines and analytics
• Write and review backend code for quality, security, and best practices
• Implement automated unit and end-to-end testing
• Participate in CI/CD processes
• Monitor, troubleshoot, and improve system stability and performance

Backend Developer, Python

• Design, develop, and maintain high-quality software using modern C++
• Contribute to browser, platform, and systems-level components across Opera products
• Develop new product capabilities and improve existing functionality
• Solve complex engineering challenges related to performance, reliability, and resource efficiency
• Investigate and resolve technical issues across application and system boundaries
• Work with complex codebases while improving architecture, maintainability, and code quality
• Collaborate with engineers across browser, product, and other technology teams
• Contribute to technical design, code reviews, and engineering best practices
• Participate in Opera's ongoing engineering talent pipeline for anticipated future hiring needs

Backend Engineer jobs in Poland

Senior Backend Engineer – Payments, Go, TypeScript, Node.js

Senior Backend Engineer, Data Core

IAM Technical Architect, German

Senior Java Developer

Middle Python Developer, ML

Senior Python Data Scraping Engineer – Freelance

Senior Python Data Scraping Engineer – Freelance

Backend Engineer – .NET

Backend Developer, Python

Senior C++ Engineer