René Doháň

• Led product specification, architecture, and implementation of the React application, TypeScript APIs and workers, AWS infrastructure, secure integrations, Stripe billing, AI support, observability, and production operations; then integrated the application with the existing Next.js marketing site and published it through Vercel.
• Built deterministic scheduled and 24/7 monitoring runtimes using queues, idempotency, retries, failure recovery, auditable state, and unit, integration, end-to-end, UI-regression, and deployed smoke tests.
• Use AI coding agents to accelerate research and implementation, with explicit specifications and direct accountability for architecture, security, review, testing, deployment, and validation.

React · Next.js · TypeScript · AWS · SST · DynamoDB · SQS · Stripe · Vercel · Vitest · Playwright · AI coding agents

Case study: Coinomatic

• Maintain both production apps, modernizing an inherited Kotlin/Java Android codebase and extending the Swift/Objective-C iOS app originally delivered in 2017.
• Deliver UI, performance, push-notification, background-sync, mapping, media, and REST integration improvements while protecting established behavior across both platforms.

Kotlin · Java · Swift · Objective-C · REST APIs · Firebase Cloud Messaging

Case study: Motorkari.cz

• Delivered iOS and Android SDK work, extended existing iOS applications, and built Swift and Kotlin sample apps that demonstrated device integration.
• Aligned Kotlin SDK behavior with its iOS counterpart and used Gherkin scenarios to define testable behavior before implementation.
• Worked API-first in a multinational remote Scrum team using Git flow, code reviews, and extensive QA practices.

Swift · Kotlin · iOS SDK · Android SDK · SDK/API design · Gherkin

Case study: Biolinq Medical SDK

• Led native Android and iOS development, translating extensive and changing public-sector requirements into working applications on both platforms.
• Implemented offline data, CSV and service-driven updates, complex form rules, and on-device validation for field workflows that could not depend on continuous connectivity.
• Coordinated months of requirements refinement, acceptance cycles, stakeholders, and supporting developers through delivery under a fixed national deadline.

Kotlin · Swift · Android · iOS · offline data · form validation

Case study: SODB 2021 Slovak Census Apps

• Built and maintain an Objective-C iPhone/iPad app, a Java Android app, and a dedicated Android scoring terminal for an international archery platform.
• Separated mission-critical competition scoring from the general product and implemented stability controls, remote device commands, polling, push messaging, and resilience for difficult outdoor Wi-Fi conditions.
• Maintain three active native products while sustaining the client relationship and deep product knowledge across an engagement active since 2014.

Objective-C · Java · Android · iOS · REST APIs · push messaging · offline resilience

Case study: Rcherz Suite