Sergii Safonov

Led Acquiring Stream (2 teams, 15 engineers) at mono — Ukraine's top neobank (9M+ clients). • Scaled payment processing for 70K+ merchants across E-com, POS, QR & Tap-to-Phone. • Automated QA in CI/CD pipelines, completely removing manual testing. • Built high-reliability culture: structured logging, key metrics & on-call duty. • Reformed team structure, hiring, and workflows to boost velocity. Tech: Golang, Kafka, RabbitMQ, Redis, PostgreSQL, K8s, Docker, GitLab CI

Led 6 engineers at Solidgate ($3B+ annual volume, 40+ PSPs, 20+ routing parameters) • Managed end-to-end payment flows: auth, capture, refunds, chargebacks • Built smart routing engine optimized for success rates & failovers • Delivered direct integrations with Visa, Mastercard, and Amex • Improved observability & delivery time (~40m); zero incidents in 9 mos • Reformed team structure, hiring, and processes to boost performance Tech: Golang, Kotlin, Kafka, RabbitMQ, Redis, Postgres, AWS, Docker, GitLab CI

Led R&D and architectural decisions for a complex blockchain-based online game (50+ services).

Designed and successfully delivered fintech rewards, e-commerce

Designed and successfully delivered the logistics system Octopus

Cryptocurrency Exchange. Node.js, TypeScript. ws, fix, rest, swagger. Postgres, Redis, RabbitMQ. Sequelize, TypeORM. Docker, Kubernetes, Helm, GitLab CI. Developing of the architecture of micro-services, their connections, security and used technologies. Configuration of a dev environment (CI/CD).

Dental Team Dentures Clear Scrum realization and development workflow organization. Part of our team was in Denmark, every day we had meetings and Skype calls in English. All of our daily meetings, demos, plannings, retro, etc was in English. Also, we had whole documentation in English (wiki, Jira, mails, etc). Development of the following cases: Full Denture, Customized Impression Tray, Removable Partial Denture, 3D Bite Plate. (Delphi, C#, 3D, WebGL, Scrum)

Java, Delphi, NodeJS, PHP Software development for State enterprise "Information judicial systems". Internal account resources, REST services, Digital signatures, Indexer. (Java, Delphi, NodeJS, PHP, PostgreSQL, Spring, Hibernate, Lucene)

Managing the work of developers team (10 - 20). Automatization developers workflow by using Atlassian Stack (Jira, Confluence, Bitbucket etc.). Taking a part in all projects stages from the beginning (idea) to support of fully working products. Developing architecture for all projects, database schemes, making decisions in uncertain moments.

Architect and Tech Lead in all projects in company. Had a small team for developing web systems. Also took a part in some projects as developer. (Delphi, PHP, Firebird, MySQL, PostgreSQL)

Document Management System for judicial system of Ukraine. (Delphi, Firebird, Yaffil, components: FIBPlus, DevExpress, QuickReport, BDE, Formula One, RX, TMS) Tools: Jira, SVN, Confluence, Inno Setup, EurekaLog. Managing the work of a team of programmers: - Analytics - Code standards definition - Task assignment - Estimation definition - Code review

Document Management System for judicial system of Ukraine. (Delphi, Yaffil, components: FIBPlus, QuickReport, BDE, Formula One, RX, TMS) Tools: Jira, CVS.

Delphi Software development for leasing, recruiting and insurance companies. "Forsage", "E-lis", "IT-Insurance" - accounting systems for companies. (Delphi, Firebird, components: FIBPlus, DevExpress, FastReport)

Freelance with a few employees. Generally: Delphi, С, PHP, MySQL, Oracle, Firebird Projects full life cycle for different clients. Some projects: Sites (based on Joomla, Virtuemart) KAP – Web site www.kap.org.ua . Show decisions of City Planning Council of the Kyiv. Statuses of people requests and documents. (PHP, MySQL, Oracle) iBuyOnline – Application for full management of internet shop www.ibo.ro . (Delphi, MySQL) MTS – Application to gathering and reporting information about clients of MTS (UMC) with

С (Embedded, ARM) Applications for POS Terminals. Projects: Keyboard – Application for testing the efficiency of POS terminals modules: display, keyboard, card reader (magnetic and chips), modem, RS232, LAN, WIFI, GPRS. OMNIPOS EMV 3 (http://www.inpas.ru/content/part/149/) – (The program complex for POS terminals). Developed some protocols for the exchange of information terminal with the banks. Supported, refined and corrected errors. As the debugging was very difficult, I received the upgrade my skill l

Company work for the Armed Forces of Ukraine. The accounting and monitoring of the presence and the status of material maintenance of the Armed Forces of Ukraine. Program complex of the accounting, monitoring and automation planning of the presence and the status of material maintenance for all services and units of the Armed Forces of Ukraine according to NATO standards. – A huge structure of a DB. – The optimized stored procedures for fast processing of the huge amount of data. (Delphi, MSSQL, Technologie

Delphi. GIS, CAD Some projects: KyivMap – Kyiv map based on vector data of Main Central Administrative Board of Architecture and Construction of Kiev. Loading objects from DB. Drawing on canvas more then 100 000 objects per sec. (Delphi, FIB , Firebird, GDI+, GIS, CAD)

С. GIS, CAD Some projects: Vector 2000 – Application at Microstation (GIS Editor) environment to automate the work of drafters. Complex mathematical algorithms for drawing vector objects. (MDL C) MapLoader - Application at Microstation (GIS Editor) environment for saving and loading vector objects from DB. Optimization, neat work with memory. (MDL C)