Denis Sazonov
Software engineer, 12+ years. Backend is my anchor, but I move between backend, DevOps & CI/CD, platform engineering, CLI tooling, and quantitative / trading systems depending on what the problem needs. Currently Lead Backend at Swipe Games — core platform, payments, public API, CI/CD, and games logic.
What I do
I design and ship production systems end-to-end. Backend is where I spend most of my time — payment flows, multiplayer game servers, public APIs, 3rd-party integrations — but I routinely step into DevOps / CI-CD, platform engineering, CLI tooling, and quantitative / trading infrastructure when a project needs it. I care about systems that stay simple as they grow: clear contracts, strong observability, and infrastructure that doesn’t fall over under real traffic.
Most of my career has been in fintech and iGaming — two domains that punish you for getting it wrong. That discipline stuck.
Highlights
- 12+ years shipping production software across fintech, iGaming, ATS, surveillance/video, and consumer products
- Led backend end-to-end on two iGaming platforms: Swipe Games and Playhub — core platform, payments, public API, games logic, CI/CD
- Scaled a casino platform to 5,000+ CCU at 1K+ RPS (Tangelo Games) and migrated it from IBM to AWS
- DRI for a B2B fintech credit card product at finmid — real-time scoring, merchant logos, risk tooling
- Built a QA API and ClearBank simulator at Fondy and wired them into existing CI/CD pipelines
- DevOps & tooling: built custom CI/CD and monitoring tools (TopDog), authored internal CLI tooling, owned GitHub Actions / Jenkins pipelines across multiple teams, Terraform + Kubernetes + Helm in production
- Quant / trading systems: deep interest in HFT and algorithmic trading infrastructure from the engineering side — low-latency services, market data handling, execution plumbing (engineer, not quant researcher)
- Co-founded and built Klever Thoughts Inc. from zero — product, team, stack; shipped desktop apps, CLI tools, and ML for image recognition
- Comfortable in Go, Kotlin, Java, TypeScript, Python, and C — picking the right tool rather than the familiar one
Areas of interest
- Backend & distributed systems — high-load, microservices, event-driven architectures
- DevOps & Platform Engineering — CI/CD, Kubernetes, Terraform, observability, infra-as-code
- CLI tools & developer experience — internal tooling, automation, dev-loop ergonomics
- Quant & trading systems (engineering side) — HFT, algorithmic trading infrastructure, low-latency services
- Fintech — payments, crypto, embedded finance, BNPL, neobanks
- Games — iGaming, meta servers, networking, multiplayer infrastructure
- AI — LLMs, agentic workflows, AI-assisted coding, building CLI tools and AI-powered workflows
- Languages — Go (Golang), Python, TypeScript, Kotlin, Java, C
Professional experience
Swipe Games — Lead Back End Developer
Jul 2025 – Present · Full-time · iGaming development and consultations
Leading the core platform, architecture, CI/CD, and games logic including high-load single- and multiplayer games — including new video-based reels (TikTok-like). Owns 3rd-party integrations, payment gateway, public API, and documentation.
Stack: iGaming · Go · Postgres · Redis · GRPC · GitHub · AWS
Playhub — Lead Back End Developer
Jan 2023 – Jul 2025 · Full-time · iGaming development and consultations
Led backend on the core platform, architecture, CI/CD, and games logic including high-load multiplayer games. Owned 3rd-party integrations, payment gateway, public API, and documentation.
Stack: iGaming · Go · Postgres · Redis · Kafka · Websockets · GRPC · GitHub · GCP
finmid — Back End Developer
Mar 2022 – Jan 2023 · Full-time · B2B credit card / BNPL fintech
DRI for the fintech credit card product. Shipped merchant logos, real-time scoring, and back-office risk-related improvements. Built the initial version of the platform public API.
Stack: Fintech · Kotlin · Java · Spring Boot · Go · Postgres · AWS · Kafka · Terraform · GitHub
Fondy — Back End Developer
Sep 2021 – Mar 2022 · Full-time · Neobank, B2B
Built a QA API from scratch for a complex fintech neobank and integrated it into the existing CI/CD pipeline. Delivered the initial version of the ClearBank simulator and supporting infrastructure.
Stack: Fintech · Java · Spring Boot · Go · GCP · Postgres · Redis · PubSub · Bitbucket
Talent Funnel — Full Stack Developer
Jun 2020 – Oct 2021 · Full-time · Applicant tracking system for HR agencies
Built external integrations (payroll providers and additional services) inside a high-load, distributed/microservices architecture.
Stack: ATS · Kotlin · Java · Spring Boot · Go · GCP · MongoDB · Redis · RabbitMQ · Bitbucket
Klever Thoughts Inc. — Lead Full Stack Developer
Oct 2017 – Dec 2023 · Part-time · Surveillance industry software
Built a full pack of editors and tools for the surveillance industry — customer management portal, video-processing desktop applications, and ML for image recognition. Helped start the company from scratch.
Stack: Video Processing · Adobe Air · Go · C · FFmpeg · Bitbucket · Windows · OSX
Tangelo Games, Israel — Back End Developer
Mar 2016 – Jul 2019 · Full-time · Facebook-based online casino platform
Refactored the platform from Smartfox to Smartfox 2 and migrated it from IBM to AWS. Delivered a new API for the Unity client. Scaled to 5,000+ CCU at 1K+ RPS. Built the initial version of BI.
Stack: iGaming · Java · Go · MySQL · Smartfox · Jenkins · Docker · AWS · Git
Christian Filipina — Full Stack Developer
Feb 2014 – Oct 2016 · Full-time · Dating portal with web and mobile apps, voice and video chat
Delivered the complete solution for the dating portal end-to-end: backend, web, and mobile apps; text and video chats; profile matching.
Stack: Java · JavaScript · Postgres · Adobe Air · Adobe Flex · Red5 · Wowza · Bitbucket
TopDog — Back End Developer
Jan 2012 – Feb 2014 · Full-time · International flights / accommodation booking portal
Built custom DevOps CD/CI and monitoring tools.
Stack: Java · Postgres · Git
Skills
Backend languages
- Java — 8 years
- Go (Golang) — 5 years
- Kotlin — 5 years
- C — 5 years (native functionality for specific projects)
- TypeScript / JavaScript — 3 years
Data & messaging
- SQL — Postgres, MySQL — 8 years
- Redis — 5 years
- Kafka, RabbitMQ, PubSub — 4 years
- MongoDB — 3 years
Cloud & infrastructure
- Docker, Kubernetes, Helm — 5 years
- GCP (Cloud Run, Functions, GKE, Cloud SQL, PubSub) — 4 years
- AWS (EC2, S3, EKS, RDS, Lambda, SQS, SNS, Kinesis) — 4 years
- Terraform, Jenkins, GitHub Actions — 4 years
APIs & protocols
- gRPC, OpenAPI/Swagger, GraphQL, REST, WebSockets — 4 years
Frontend / Node
- Node.js, React.js — 4 years
Go ecosystem
- testify, mockify, gomock, logrus, go-openapi, xo, squirrel, gin, echo, protobuf/grpc — 5 years
Tools
- IntelliJ IDEA, VS Code — 10 years
Education
- M.Sc. in IT — Microcontrollers and Processor Programming. Moscow Power Engineering Institute
Languages
- Russian — native
- English — B2
Get in touch
Fastest ways to reach me: LinkedIn · GitHub · Telegram · Twitter/X · Medium · Upwork
Open to full-time, contract, and consulting work — especially roles where backend systems actually have to work under real load.