Alex Sirchenko
Verified Expert in Engineering
Full-stack Software Engineer and Developer
Kiev, Ukraine
Toptal member since June 5, 2020
Alex is a full-stack developer with 8+ years of experience specializing in React, TypeScript, and Node.js. He's built scalable web apps, custom Salesforce integrations, and internal tools using Salesforce APIs. Alex is experienced in designing SQL workflows, automations, and cross-channel customer journeys, and he delivers production-ready solutions within Agile, cross-functional teams.
Portfolio
Experience
- Docker - 8 years
- React - 8 years
- Node.js - 8 years
- TypeScript - 8 years
- Full-stack Development - 8 years
- Salesforce - 6 years
- Web App Development - 5 years
- Next.js - 4 years
Preferred Environment
TypeScript, React, Node.js, Full-stack, Python, Amazon Web Services (AWS), AI Agents, Software Architecture
The most amazing...
...work I've done is building a Next.js cross-channel app to connect Salesforce Marketing Cloud with the system via custom activity, including a full CI set up.
Work Experience
Lead Full-stack Software Developer
MailSplash AI LLC
- Led the transition of an AI-powered email platform from MVP to production readiness, auditing the Next.js/Firebase codebase, prioritizing critical gaps, and defining the production roadmap.
- Developed and maintained the mobile CRM application using React Native, delivering new features and cross-platform improvements for iOS and Android, and supporting 6,000+ users.
- Designed and enhanced backend-for-frontend (BFF) services with NestJS, building API integrations and business logic that streamlined communication between front-end applications and back-end services.
- Developed back-end services and APIs using Python and FastAPI, implementing business logic, integrations, validation, and scalable API endpoints to support AI and platform workflows.
- Optimized PostgreSQL queries and data access using Drizzle ORM and Prisma, improving query performance by 20%, reducing response times, and improving maintainability and type safety.
- Implemented missing product capabilities and resolved core stability issues across React, TypeScript, Firebase, Supabase, Prisma, NestJS, and FastAPI, accelerating the platform’s transition from MVP to production.
- Built an AI-driven video-generation pipeline integrating multiple providers, including Sora and Veo 3, as well as faceless and UGC workflows, enabling automated multimedia content creation and expanding the platform’s AI capabilities.
- Integrated Stripe payments, subscriptions, and billing workflows, enabling secure transactions and supporting 1,000+ subscriptions.
- Introduced AI-assisted development workflows using Claude and Cursor, reducing development time for selected tasks by 50% and improving delivery speed, code quality, and developer productivity.
Back-end Software Developer
Art Smart Adventures Inc.
- Diagnosed and resolved critical API integration issues between the company website and two third-party booking systems, restoring full booking functionality and preventing loss of customer reservations.
- Troubleshot and stabilized Stripe payment integrations, ensuring successful transaction processing and accurate booking confirmations across all tours.
- Implemented robust error handling and logging in Node.js to improve system reliability and make future troubleshooting more efficient.
- Collaborated with stakeholders to document the integration architecture, identify recurring issues, and recommend long-term improvements for API resilience.
Lead Full-stack Software Engineer
Volvo Cars
- Led a cross-functional engineering team of 4 software engineers, defining development, testing, and release strategies for Salesforce Marketing Cloud campaigns, ensuring scalable, high-quality customer engagement solutions.
- Designed and deployed AWS-backed infrastructure (S3, SQS, Lambda, Cognito) supporting event-driven data pipelines, with a focus on scalability and operational reliability.
- Implemented shared native SDK integrations (push notifications, analytics, authentication, deep linking, and crash reporting) across React Native and Flutter modules to ensure consistent mobile platform behavior.
- Developed and maintained back-end services in Java for enterprise-scale applications, focusing on system stabilization, bug fixing, and new feature implementation.
- Built and optimized RESTful APIs and microservices using Java and Spring Boot, improving application performance, reliability, and scalability for high-volume customer workflows.
- Developed a custom Marketing Cloud reporting dashboard using React and Node.js, leveraging Salesforce APIs to provide actionable insights and improve visibility into journey performance.
- Built high-throughput back-end services in Python and Node.js to process and route large volumes of structured data, integrating with downstream ML workflows and third-party APIs.
- Created and managed audience segmentation strategies using Data Extensions and SQL queries.
- Monitored campaign performance, data quality, and delivery processes to ensure reliable customer communications.
- Designed and implemented a custom Salesforce Marketing Cloud activity integrated with the Iterable system using a Next.js and TypeScript application.
Lead NetSuite Software Engineer
DataArt
- Leveraged NetSuite API to generate test data for Sales Orders, Purchase Orders, Item Adjustments, and other record types, enabling automated testing and validation of business workflows across multiple environments.
- Developed a NetSuite application for large-scale data generation within the UI using React and SuiteScript 2.0, enabling users to efficiently create and manage bulk test records directly from a custom interface.
- Automated web applications using JavaScript and TypeScript, Protractor, and Jasmine, as well as managed test execution on CI (TeamCity).
- Migrated the existing Protractor framework to Playwright, seamlessly integrating the solution with the custom integration testing framework.
- Led and managed a team of four QA automation engineers, overseeing test strategy and execution.
- Optimized Map/Reduce and scheduled scripts for performance.
- Implemented performance automation tests using k6.io.
- Migrated an automation project from JavaScript to TypeScript.
- Facilitated the interview process for incoming team members.
Front-end Software Developer
ReadySet Technologies
- Delivered new UI for a VR eCommerce app with TypeScript, React, Redux, and Hooks, implementing responsive, accessible, and maintainable front-end components.
- Refactored codebase to improve performance and readability; introduced scalable React patterns and best practices.
- Implemented best practices for scalable and maintainable React development.
- Set up CI/CD from scratch in GitLab using runners and Docker Compose, designing pipelines for lint/build/test, managing artifacts and secrets, and automating deployments (beyond test execution alone).
- Optimized UX via code-splitting, lazy loading, and performance profiling to improve Core Web Vitals.
- Designed and implemented unit and end-to-end (E2E) automation tests for the web application.
Software Developer in Test
Star (formerly Cogniance)
- Automated web applications using JavaScript, TypeScript, and Cypress.io.
- Managed test execution on CI using Docker and Travis.
- Implemented performance automation tests using JMeter.
- Created integration tests using the Java Testcontainers library.
- Ran sprint reviews for the customer, along with managing the release.
QA Automation Engineer
PitchBook
- Worked on market data systems covering public companies, investors, funds, venture capital, and private equity, ensuring accuracy and reliability of financial data.
- Built and maintained a Java-based E2E automation framework, integrating API testing with RestAssured for validation of RESTful services and end-to-end business flows.
- Conducted performance and API testing for high-volume financial datasets, identifying and reporting key issues that improved system scalability.
- Designed and implemented automated test suites using Selenium (Java), improving regression coverage.
QA Automation Engineer
Infopulse
- Designed, developed, and maintained automated test frameworks in Python for web and API testing.
- Built and integrated automated regression suites into CI/CD pipelines using Azure DevOps.
- Implemented and maintained API tests using Requests and HTTPX, validating responses with JSON schema validation to ensure contract integrity and reliability.
- Designed and executed unit, integration, and end-to-end test suites using pytest, improving application stability and confidence in deployments.
- Performed code reviews, static analysis, and contributed to testability improvements in production code.
QA Automation Engineer
TestMatick
- Developed and implemented UI automation tests from scratch using JavaScript with Detox for iOS mobile testing and WebdriverIO for web applications.
- Set up and managed test execution on Jenkins, creating and maintaining CI/CD pipelines.
- Developed and updated test suites and test cases, and extended test coverage. Also created a traceability matrix for the customer.
- Communicated with the customer to analyze and investigate defects.
- Configured a reporting system for clear test execution insights and issue tracking.
- Contributed to development by identifying and fixing bugs and enhancing overall software quality.
Experience
Healthcare Appointment and Patient Engagement Mobile Platform
Next.js App for Marketing Cloud Cross-channel
The application features a React-based UI for marketers to set input parameters, combined with back-end logic that manages secure data transmission and API authentication. It leverages Salesforce’s custom activity SDK to allow drag-and-drop configuration within Journey Builder and ensures state persistence via SFMC interfaces. To support enterprise workflows, the app is integrated into a Heroku CI/CD pipeline, automating build, test, and deployment processes, enabling rapid iteration and stable releases. Error tracking and logging are implemented to enhance reliability and maintainability.
The project involved working with new APIs and tools, requiring comprehensive problem-solving and cross-platform integration across the full development lifecycle, from architecture to deployment.
AI-driven Email Marketing Simplified
This tool stands out as a cost-effective alternative to traditional email marketing solutions, consolidating multiple functionalities into one platform. Users can navigate the user-friendly interface with ease, generate tailored emails quickly, and maintain brand consistency through customizable design features. While Mailsplash does leverage AI to streamline email generation, users still have the option to edit and approve the final output, ensuring that the emails align with their brand's voice and marketing objectives.
Education
Speсialist's Degree in Fire Safety Engineering
Academy of Fire Safety - Cherkasy, Ukraine
Certifications
Salesforce Certified Marketing Cloud Administrator
https://www.salesforce.com/trailblazer
Salesforce Certified Marketing Cloud Developer
Salesforce
Salesforce Certified Marketing Cloud Email Specialist
https://www.salesforce.com/trailblazer
ISTQB Certified Tester Foundation Level
ISTQB — International Software Testing Qualifications Board
Professional Scrum Master I
Scrum.org
Skills
Libraries/APIs
Node.js, REST APIs, React, Selenium WebDriver, Salesforce REST API, Salesforce SOAP API, Playwright, NetSuite API, React Query, Zod, SOAP APIs, Google Calendar API, React Testing Library, Drizzle, Vue, Stripe, Stripe API, OpenAI API, OpenAPI, Claude API, MobX, Shopify API
Tools
Git, TFS, Jenkins, Jira, TestRail, Apache JMeter, Gatling Load Testing, GitLab CI/CD, Postman, Mocha, Pytest, Docker Compose, JSX, Salesforce Marketing Cloud, Webpack, Cucumber, Lighthouse, Webpack Module Federation, TanStack Router, Prisma, Figma, REST Assured, TeamCity, Travis CI, Grafana k6, GitLab Runner, Redux Toolkit, Terraform, Firebase Authentication, Claude Code, Claude, Apache Maven, xUnit, GitLab, GitHub, ChatGPT, Retool, Pardot, Drizzle ORM, Shadcn
Languages
TypeScript, Python, JavaScript, Java, SQL, CSS, AMPscript, HTML, GraphQL, SuiteScript 1, SuiteScript 2, Elixir, Python 3, C#, PHP, Snowflake
Frameworks
Selenium, Cypress, Protractor, Appium, React Native, Detox, Next.js, NestJS, Redux, Jest, Tailwind CSS, Express.js, Swagger, Selenide, Spring Boot, Jasmine, TestCafe, Django, AngularJS, JUnit, NUnit, Angular, .NET, JUnit 5, TestNG, Flutter
Paradigms
Manual Testing, Test Automation, Load Testing, Automation, DevOps, Automated Testing, Testing, Microservices, Azure DevOps, Database Design, ETL, Search Engine Optimization (SEO), Serverless Architecture
Platforms
Docker, Amazon EC2, Amazon Web Services (AWS), iOS, Salesforce, Firebase, Apache Kafka, Azure, Vercel, Google Cloud Platform (GCP), MacOS, Iterable, Heroku, Kubernetes, AWS Lambda, WordPress, Amazon, PostHog, Android, Klaviyo, Shopify
Storage
PostgreSQL, MySQL, Amazon S3 (AWS S3), MongoDB, JSON, Google Cloud, Data Lakes, NoSQL, Data Pipelines, Elasticsearch, Microsoft SQL Server, Redis
Industry Expertise
Marketing, Automotive
Other
Certified ScrumMaster (CSM), QA Automation, Quality Assurance (QA), Mobile Device QA Automation, Performance Testing, Integration Testing, Mobile App Testing, Web App Testing, Regression Testing, Data Modeling, Data Management, Web App Development, QA Testing, Web Development, Full-stack, Software Architecture, NetSuite, Front-end, API Integration, Application State Management, CI/CD Pipelines, Front-end Development, React Hooks, APIs, Enterprise Resource Planning (ERP), Architecture, AWS DevOps, Leadership, Server-side Rendering (SSR), User Experience (UX), Technical Leadership, Back-end, API Gateways, Authentication, Responsive UI, Code Review, Source Code Review, Task Analysis, Technical Hiring, Interviewing, Team Management, API Testing, Automated UI Testing, Manual QA, Health, ESLint, Content Delivery Networks (CDN), User Interface (UI), eCommerce, Design Systems, SDET, Engineering Management, Team Mentoring, Software Testing Automation Framework (STAF), General Data Protection Regulation (GDPR), UI Components, UI Testing, Salesforce Marketing Cloud, Digital Marketing, Full-stack Development, ISTQB, Data Warehousing, AI Programming, REST API Automation, SAP CRM, System Administration, Salesforce, FastAPI, Vite, Single Sign-on (SSO), Dashboards, Tailwind UI, Startups, SaaS, Cross-browser Testing, Cloudflare, LangChain, AI Agents, WebSockets, Supabase, OAuth, Web Scraping, Apple Pay, Google Pay, NetSuite Connector, Inventory Management, Warehouse Management, Warehouse Operations, Supply Chain, Warehouse Management System (WMS), GitHub Actions, Serverless, Fractional CTO, CTO, Zustand, Enterprise Architecture, Static Site Generators, Artificial Intelligence (AI), Big Data, Cursor AI, Videos, AI Automation, AI Tools, Video Processing, Web & Mobile Applications, Enterprise, Server-side JavaScript, Large Language Models (LLMs), AI Integration, OpenAI, Engineering, Anthropic, Framer, Data Analytics, GDPR, Hono API, Neon DB, Video APIs, Veo
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