Full-stack software engineer building payment systems, fintech applications, SaaS platforms, and distributed business software from Nairobi, Kenya.

• Payment infrastructure & integrations — production M-Pesa Daraja integrations including STK Push, C2B, B2C, Paybill/Till workflows, callback processing, transaction status handling, reconciliation, payment notifications, retry mechanisms, and integration abstractions for connecting applications with payment providers.

• Financial software & transaction systems — digital wallet components, account ledgers, transaction histories, balance management, payment tracking, invoicing, billing workflows, reconciliation tools, financial reporting, merchant dashboards, and auditable transaction processing.

• API-driven platforms — REST APIs and backend services designed around authentication, authorization, request validation, rate limiting, structured error handling, idempotency, webhooks, background jobs, caching, logging, and reliable third-party integrations.

• Distributed & event-driven systems — asynchronous processing pipelines using queues, workers, Redis, event-driven workflows, scheduled jobs, webhook consumers, retry strategies, and service-to-service communication for applications that need reliability beyond a single request/response cycle.

• SaaS & multi-organization applications — scalable business platforms with organization-aware data models, role-based permissions, subscription and billing workflows, administrative dashboards, tenant isolation, configurable business rules, audit trails, notifications, and API access.

• Business automation platforms — systems that connect payment providers, messaging services, internal business tools, databases, and external APIs to automate repetitive operational workflows and reduce manual processing.

• Real-time applications — WebSocket services, live dashboards, real-time notifications, event broadcasting, Redis pub/sub, connection management, background processing, and state synchronization between clients and backend services.

• Offline-first applications — Progressive Web Applications designed for environments with unreliable connectivity, using local storage, IndexedDB, synchronization queues, conflict handling, and eventual synchronization with backend services.

• Messaging & commerce integrations — WhatsApp Business API integrations, Telegram bots, SMS workflows, automated notifications, subscription management, customer communication systems, and API-driven messaging workflows.

• Data & business intelligence — transaction reporting, operational dashboards, analytics pipelines, data aggregation, business metrics, database optimization, and systems that turn application data into useful operational insights.

• Security & application architecture — authentication systems, authorization, API security, secure credential handling, signed requests, webhook verification, input validation, database constraints, audit logging, and defensive backend design.

• Production infrastructure — Linux servers, Nginx reverse proxies, Docker, systemd services, GitHub Actions CI/CD, SSL/TLS configuration, DNS, database administration, application deployment, monitoring, logging, and VPS infrastructure.

My work sits at the intersection of software engineering, financial technology, APIs, distributed systems, and business automation.

I particularly enjoy working on systems where reliability and data integrity matter — especially applications involving payments, transactions, external APIs, asynchronous processing, and real-time communication.

Some areas I work with include:

• Payment processing workflows
• Transaction lifecycle management
• API architecture
• Webhook-driven systems
• Distributed background processing
• Idempotent transaction handling
• Database consistency
• Caching strategies
• Real-time communication
• Authentication & authorization
• Business workflow automation
• Observability and structured logging
• Cloud and VPS deployments

• Building payment-focused software and reusable integrations around modern financial APIs
• Developing business platforms with Laravel, React, Python, and MySQL
• Working on transaction processing, reconciliation, reporting, and financial workflows
• Building API-driven automation connecting business systems and external services
• Improving production infrastructure, deployment workflows, and application reliability

Backend Engineering

Laravel • PHP • Python • Node.js • FastAPI • REST APIs • WebSockets • Queues • Background Jobs

Frontend Engineering

React • Next.js • TypeScript • Tailwind CSS • Progressive Web Apps • Offline-first applications

Data & Infrastructure

MySQL • Redis • Linux • Nginx • Docker • VPS • CI/CD • GitHub Actions

Payments & Integrations

M-Pesa Daraja • Payment APIs • Webhooks • Transaction Processing • Reconciliation • Notifications • API Integrations

Architecture

Event-driven systems • Distributed processing • Caching • Idempotency • Authentication • Authorization • Role-based access control

Freelance and contract — payment integrations, fintech software, SaaS platforms, backend systems, REST APIs, business automation, Laravel applications, Python services, React applications, database-driven systems, and cloud infrastructure.

Stack: Laravel, PHP, Python, TypeScript / React, Node.js, MySQL, Redis, Docker, Linux.

Reach me at hi@felixmuhoro.dev or via felixmuhoro.dev.