Denys Demchenko is a web development lead at PLANEKS with deep expertise in FastAPI and Flask, microservices architecture, and payment gateway integrations. He helps startups and growth-stage companies ship reliable, high-performance web platforms by aligning product goals with clear technical roadmaps—so teams can move from MVP to scale with confidence.
Denys focuses on Python web development using FastAPI/Flask, OpenAPI-driven contracts, and event/webhook patterns that keep services decoupled and easy to evolve. He designs microservices with clean boundaries, async processing, and observability (tracing, metrics, logging) to keep latency low and uptime high.
A key part of Denys’s work is payment enablement: integrating providers such as Stripe/Adyen/PayPal, implementing 3-D Secure, recurring billing and subscriptions, refunds, payouts, and idempotent webhook handling to prevent double charges. He also advises on gateway selection, risk/fraud tooling, and the operational playbooks that keep checkout conversion and finance reconciliation on track.
Focus areas: FastAPI & Flask web development, microservices & async workers, payment gateway integration (3-D Secure, webhooks, recurring), performance tuning, reliability engineering, and secure release practices from MVP to scale.
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