Yohannes is available for hire
Hire YohannesYohannes Mesay
Verified Expert in Engineering
System Architecture Developer
Addis Ababa, Ethiopia
Toptal member since October 7, 2026
Bio
Yohannes is a full-stack developer specializing in React, Next.js, and Node.js/NestJS, building production-grade web applications end-to-end. He recently architected a multi-tenant Banking-as-a-Service platform for a fintech client, handling compliance, account management, and payment infrastructure. He also builds AI agents, chatbots, and automation workflows as part of his development practice
Portfolio
An Online Freelance Agency
API Integration, Database Design, Docker, Next.js, System Design, Express.js...
Immigration Law Firm
Database Design, API Integration, Next.js, Docker, PostgreSQL, Open Source...
Backos Technologies
API Integration, Jira, Database Design, Docker, Express.js, Git, GitHub...
Experience
- Full-stack - 5 years
- System Architecture - 5 years
- React - 4 years
- TypeScript - 4 years
- Git - 4 years
- Next.js - 4 years
- PostgreSQL - 4 years
- NestJS - 3 years
Work Experience
Full-Stack Engineer & Software Architect
2024 - PRESENT
An Online Freelance Agency
- Built a Banking-as-a-Service platform on Apache Fineract, an open-source core banking ledger, extended with custom account and transaction services.
- Implemented KYC/AML compliance and multi-currency account support for a regulated, multi-tenant fintech platform.
- Designed inventory and order-tracking systems synced with Stripe payments, giving the business real-time visibility into stock and sales.
- Developed a property tax management platform that streamlined property information, pricing, and tax-related workflows through a centralized web application.
- Built a full-stack eCommerce and CRM platform for a comic book retailer, integrating Stripe for end-to-end checkout and payment processing.
- Performed full-stack development and system design for high-performance applications.
Technologies: API Integration, Database Design, Docker, Next.js, System Design, Express.js, React, Git, GitHub, TypeScript, Full-stack, Large Language Models (LLMs), Artificial Intelligence (AI), Claude Code, AI-assisted Development, AI Integration, Claude, Cursor AI, Amazon Web Services (AWS), AI Tools, Agentic AI, AI Agents, Financial Services, Digital Banking, Apache Fineract, Databases, Spreadsheets, PostgreSQL, HTML5, CSS, CRM, Sanity Studio, Workflow Automation, Technical SEO, Web Development, Full-stack Development, CI/CD Pipelines, Software Architecture, Front-end, Single-page Applications (SPAs), Angular, REST APIs, Streaming, Orchestration, LLM Agents, Amazon S3 (AWS S3), Vite, Drizzle, Prisma, Instagram, Shopify, APIs, CSS3, HTML, AWS Lambda, DevOps, Back-end, Serverless Framework, BigCommerce, eCommerce, AI Consulting, AI Workflow, Automation, Integration, Integrations, ChatGPT API, Claude API, Reporting, ChatGPT, Python, AI Engineering, RAG Systems, Software Engineering, LangChain, Web Content Accessibility Guidelines (WCAG), GraphQL, System Architecture, Rust, API Architecture, Component-based Architecture, Design Systems, Microservices, Jenkins, Codex, Security, Architecture, Scraping, Jest, React Native, NestJS, Visual Studio Code (VS Code), Visual Studio, React Testing Library, Webpack, System Requirements, Web Applications, User Interface (UI), OpenAI, SaaS, Web App Development, Minimum Viable Product (MVP), UI Design, Marketplaces, Mobile UX, Mobile Development, AI-generated Code, Compliance, GDPR, Expo, Supabase Auth, Offline Data Synchronization, API Development, Retrieval-augmented Generation (RAG), Prompt Engineering, Tailwind CSS, Node.js, Shadcn UI, Tailwind UI, Back-end Development, Software Development, Front-end Development, Software Development Lifecycle (SDLC), Business Services, JavaScript, Android, Mobile Architecture, Application State Management, Push Notifications, AI Chatbots, LLM Integration, Chatbots, Stripe, AI Voice Agents, AWS IoT, Vector Databases, Redux, Email Integration, Material UI, Payments, QR Codes, React Hooks, Responsive UI, Vercel
Full-stack Developer
2025 - 2026
Immigration Law Firm
- Integrated 10+ services, including Stripe, Docassemble, Documenso, Chatwoot, Nextcloud, and USCIS, into a unified staff CRM and client portal workflows.
- Designed and built a white-label immigration law platform replacing a legacy CRM for a Massachusetts immigration firm.
- Implemented VAWA-compliant PII redaction and immutable audit logging so sensitive client data access is restricted, logged, and traceable by role.
- Delivered multilingual staff and client experiences across 4 locales (English, Portuguese-BR/PT, Spanish) with locale-prefixed routing via next-intl.
- Modeled 16 immigration case types and the full matter lifecycle: intake wizard, questionnaires, documents, deadlines, billing, and e-signatures.
- Containerized production with multi-stage Docker builds, standalone Next.js output, and automated Prisma migrations on container startup via Coolify.
- Structured the codebase into 14 domain modules using Server Actions, shared Zod schemas, and cached services for maintainable staff and portal features.
Technologies: Database Design, API Integration, Next.js, Docker, PostgreSQL, Open Source, GitHub, Git, Twilio, Chatbox, AI Chatbots, SEO Tools, WhatsApp Business, Stripe, E-signatures, DocuSign, Full-stack, Large Language Models (LLMs), Claude Code, AI-assisted Development, AI Integration, Claude, Cursor AI, Artificial Intelligence (AI), AI Tools, Agentic AI, AI Agents, Databases, Spreadsheets, JavaScript, TypeScript, Express.js, React, HTML5, CSS, Technical SEO, Web Development, Full-stack Development, CI/CD Pipelines, Software Architecture, Front-end, Single-page Applications (SPAs), REST APIs, Orchestration, LLM Agents, Amazon S3 (AWS S3), Vite, Prisma, APIs, CSS3, HTML, DevOps, Back-end, AI Workflow, Integration, Integrations, ChatGPT API, Reporting, ChatGPT, Software Engineering, Web Content Accessibility Guidelines (WCAG), System Architecture, API Architecture, Component-based Architecture, Design Systems, Security, Architecture, Jest, NestJS, Visual Studio Code (VS Code), Visual Studio, React Testing Library, Webpack, Web Applications, User Interface (UI), OpenAI, Web App Development, Minimum Viable Product (MVP), UI Design, AI-generated Code, Compliance, GDPR, Offline Data Synchronization, API Development, Retrieval-augmented Generation (RAG), Prompt Engineering, Tailwind CSS, Node.js, Shadcn UI, Tailwind UI, Back-end Development, Software Development, Front-end Development, Software Development Lifecycle (SDLC), Business Services, Mobile Architecture, Application State Management, Push Notifications, LLM Integration, Chatbots, AI Voice Agents, Redux, Email Integration, Material UI, Payments, QR Codes, React Hooks, Responsive UI, Vercel
Full-Stack Engineer & Software Architect
2022 - 2024
Backos Technologies
- Architected and integrated a WebRTC video-chat module used daily by more than 950 teachers and parents.
- Boosted appointment bookings by 30% through the scheduling dashboard.
- Built the core back-end and data model for a healthcare appointment platform covering scheduling, patient records, and staff management.
- Architected and deployed a full-scale school management platform serving 1,000+ students, teachers, and parents across multiple role-based dashboards.
- Built a real-time parent-teacher chat system using WebSockets, reducing communication delays and replacing manual phone-based coordination.
- Developed an attendance tracking system with automated alerts to parents, improving daily reporting accuracy across all classrooms.
- Built a grade management module with exportable reports, replacing a fully manual spreadsheet-based workflow used by the institution.
- Delivered the platform end-to-end from database schema to production deployment, including CI/CD pipeline setup and environment configuration.
- Designed the core front-end architecture and state-management approach used across multiple modules of an appointment scheduling ERP.
Technologies: API Integration, Jira, Database Design, Docker, Express.js, Git, GitHub, JavaScript, Jest, ClickUp, Linux, NestJS, MongoDB, Next.js, Node.js, Deno, Postman, Python, React, n8n, Redux, Slack, Socket.IO, Supabase, System Architecture, System Design, System Requirements, Tailwind CSS, TypeScript, Zod, Full-stack, Large Language Models (LLMs), AI-assisted Development, AI Integration, Claude, Cursor AI, Artificial Intelligence (AI), AI Tools, Agentic AI, AI Agents, Databases, Spreadsheets, PostgreSQL, HTML5, CSS, Technical SEO, Web Development, Full-stack Development, Software Architecture, Front-end, Single-page Applications (SPAs), Java, Spring, REST APIs, Streaming, Orchestration, LLM Agents, Vite, Drizzle, Prisma, Shopify, APIs, CSS3, HTML, DevOps, Back-end, Serverless Framework, eCommerce, AI Workflow, Automation, Integration, Integrations, ChatGPT API, Reporting, ChatGPT, AI Engineering, Software Engineering, Web Content Accessibility Guidelines (WCAG), GraphQL, PHP, Amazon Web Services (AWS), API Architecture, Component-based Architecture, Design Systems, Microservices, Jenkins, Laravel, Figma, Security, Architecture, Scraping, Playwright, React Native, Visual Studio Code (VS Code), Visual Studio, React Testing Library, Webpack, Web Applications, User Interface (UI), Browser Automation, Gemini, OpenAI, SaaS, Web App Development, Minimum Viable Product (MVP), UI Design, Marketplaces, Mobile UX, Mobile Development, AI-generated Code, Compliance, GDPR, Expo, Supabase Auth, Offline Data Synchronization, API Development, Retrieval-augmented Generation (RAG), Prompt Engineering, Shadcn UI, Tailwind UI, Back-end Development, Software Development, Front-end Development, Software Development Lifecycle (SDLC), Business Services, Android, Mobile Architecture, Application State Management, Push Notifications, AI Chatbots, LLM Integration, Chatbots, Stripe, AWS IoT, Vector Databases, Email Integration, Material UI, Payments, QR Codes, React Hooks, Responsive UI, Vercel
Front-end-focused Full-stack Engineer
2021 - 2022
Backos Technologies
- Gathered client requirements through direct discussions, mapped business workflows, and translated their needs into practical system features and user-focused solutions.
- Designed and developed responsive, user-friendly interfaces with reusable components and maintainable frontend architecture, aligning the user experience with client requirements.
- Tested application workflows, identified and fixed defects, and improved performance, reliability, and security to deliver stable applications that met functional and user requirements.
- Prepared clear technical documentation, setup instructions, and user guides to help clients navigate their systems, test delivered features, and manage day-to-day workflows.
- Optimized frontend rendering, resource usage, and responsive layouts to improve page responsiveness, provide smoother interactions, and deliver a better user experience.
Technologies: Front-end, Next.js, React, TypeScript, Jest, REST APIs, API Integration, Deployment, MkDocs, Web Applications, User Interface (UI), Gemini, OpenAI, SaaS, Web App Development, Minimum Viable Product (MVP), UI Design, Marketplaces, Mobile UX, Mobile Development, Compliance, GDPR, Expo, Supabase Auth, Offline Data Synchronization, API Development, Tailwind CSS, Python, Shadcn UI, Tailwind UI, Full-stack Development, Back-end Development, Software Development, Front-end Development, Software Development Lifecycle (SDLC), Business Services, JavaScript, React Native, Android, Mobile Architecture, Application State Management, Push Notifications, Node.js, AI Chatbots, LLM Integration, PostgreSQL, Stripe, Redux, Email Integration, Material UI, Payments, React Hooks, Responsive UI
Project History
Banking-as-a-Service Platform
I architected and built a multi-tenant Banking-as-a-Service platform for fintech companies and neobank builders. I worked across the full stack, including system architecture, data modeling, REST API design, account management, transaction processing, balance tracking, and 3rd-party financial integrations.
The platform used Apache Fineract as its core banking and ledger foundation and added custom services for IBAN accounts, digital wallets, multi-currency payments, and card issuing. I also implemented KYC/AML workflows and transaction monitoring for a regulated financial product, with isolated workspaces for different clients. My role covered technical architecture, back-end services, database design, integrations, and infrastructure decisions.
The platform used Apache Fineract as its core banking and ledger foundation and added custom services for IBAN accounts, digital wallets, multi-currency payments, and card issuing. I also implemented KYC/AML workflows and transaction monitoring for a regulated financial product, with isolated workspaces for different clients. My role covered technical architecture, back-end services, database design, integrations, and infrastructure decisions.
Music & Video Streaming Platform
https://afrombira.com/AfroMbira is a production music and video streaming platform that brings together media delivery, subscription management, authentication, and content administration. I developed core parts of the consumer application and admin dashboard, contributing to a platform designed to support ongoing usage and continued growth.
My work included integrating HLS playback through Cloudflare Stream, implementing authentication and subscription workflows, integrating Stripe payments, and building API-driven interfaces for content discovery and management. I also worked on application state management, automated testing, and reliable communication between front-end components and back-end services. The platform brings together multiple services within a unified experience, with an architecture designed to support maintainability, additional features, and future client applications.
My work included integrating HLS playback through Cloudflare Stream, implementing authentication and subscription workflows, integrating Stripe payments, and building API-driven interfaces for content discovery and management. I also worked on application state management, automated testing, and reliable communication between front-end components and back-end services. The platform brings together multiple services within a unified experience, with an architecture designed to support maintainability, additional features, and future client applications.
Cactus Browser: Native Linux Web Browser (Rust, WebKitGTK, GTK4)
https://cactus-browser.tech/Cactus Browser is a native Linux-first web browser I designed and built in Rust. I architected a multi-crate workspace (core, UI, WebKit integration, and privacy) and implemented the desktop shell using GTK4 and libadwaita, including multi-tab browsing, an omnibox with suggestions, bookmarks, history, downloads, private windows, and session restore. I integrated WebKitGTK 6 for rendering and hooked navigation policy to block ads and trackers using EasyList/EasyPrivacy, plus cosmetic CSS filtering and a local privacy dashboard with zero first-party telemetry. Persistent state lives in SQLite and TOML under standard XDG paths. I set up GitHub Actions to deploy the marketing site to a custom domain (cactus-browser.tech), wrote build/docs for contributors, and shipped the project under MPL-2.0 as an open-source daily driver for GNOME/Wayland.
Education
2020 - 2024
Bachelor's Degree in Software Engineering
Addis Ababa Science and Technology University - Addis Ababa, Ethiopia
Skills
Libraries/APIs
Zod, Node.js, React, Stripe, REST APIs, Drizzle, Claude API, React Testing Library, API Development, Playwright, Socket.IO, Stripe API
Tools
Git, GitHub, Claude Code, Claude, AI SDK, Spreadsheets, Prisma, ChatGPT, Jenkins, Codex, Visual Studio, Webpack, Expo, Shadcn UI, Figma, Drizzle ORM, n8n, Slack, Jira, Postman, Chatbox, Amazon Elastic Container Service (ECS), GNOME
Languages
TypeScript, JavaScript, Python, Coolify, HTML5, CSS, CSS3, HTML, GraphQL, Java, PHP, Rust
Frameworks
Next.js, Tailwind CSS, Redux, Express.js, React Native, NestJS, Angular, Serverless Framework, Laravel, Material UI, Jest, Spring, Selenium
Paradigms
DevOps, Automation, API Architecture, Microservices, UI Design, Mobile Development, Database Design
Platforms
Docker, Visual Studio Code (VS Code), Amazon Web Services (AWS), Apache Fineract, Sanity Studio, Android, AWS IoT, Vercel, Twilio, Shopify, AWS Lambda, BigCommerce, Linux
Storage
MongoDB, PostgreSQL, Databases, Amazon S3 (AWS S3), SQLite
Other
Supabase, System Architecture, API Integration, AI Chatbots, Full-stack, Chromium, APIs, Security, Cursor AI, Artificial Intelligence (AI), Large Language Models (LLMs), Banking as a Service (BaaS), AI Integration, AI Tools, AI-assisted Development, Agentic AI, AI Agents, Financial Services, Digital Banking, Support, Streaming, CRM, Workflow Automation, Technical SEO, Web Development, Full-stack Development, CI/CD Pipelines, Software Architecture, Front-end, Single-page Applications (SPAs), Orchestration, LLM Agents, Vite, Back-end, eCommerce, AI Consulting, AI Workflow, Integration, Integrations, ChatGPT API, Reporting, AI Engineering, RAG Systems, Software Engineering, LangChain, Web Content Accessibility Guidelines (WCAG), Component-based Architecture, Design Systems, Architecture, Scraping, Web Applications, User Interface (UI), Browser Automation, Gemini, OpenAI, SaaS, Web App Development, Minimum Viable Product (MVP), Marketplaces, Mobile UX, AI-generated Code, Compliance, GDPR, Supabase Auth, Offline Data Synchronization, Retrieval-augmented Generation (RAG), Prompt Engineering, Tailwind UI, Back-end Development, Software Development, Front-end Development, Software Development Lifecycle (SDLC), Business Services, Mobile Architecture, Application State Management, Push Notifications, LLM Integration, Chatbots, AI Voice Agents, Vector Databases, Email Integration, Payments, QR Codes, React Hooks, Responsive UI, WhatsApp Business, Instagram, Deno, System Requirements, System Design, Algorithms, ClickUp, Open Source, SEO Tools, E-signatures, DocuSign, Privacy engineering, WebKitGTK, GTK4, Privacy, Deployment, MkDocs
Collaboration That Works
How to Work with Toptal
Toptal matches you directly with global industry experts from our network in hours—not weeks or months.
1
Share your needs
Discuss your requirements and refine your scope in a call with a Toptal domain expert.
2
Choose your talent
Get a short list of expertly matched talent within 24 hours to review, interview, and choose from.
3
Start your risk-free talent trial
Work with your chosen talent on a trial basis for up to two weeks. Pay only if you decide to hire them.
Top talent is in high demand.
Start hiring