I build beautiful, high-converting e-commerce stores, high-speed Next.js websites, and robust NestJS business systems (POS, ERP, CRM) with seamless payment integrations (M-Pesa, Stripe, cards). Optimized for speed, search visibility, and checkout conversion — taking products from raw idea to first paying customer.
Taking on new projects · E-commerce, websites, payment integrations & business systems.
I'm Valentine, a freelance full-stack engineer in Nairobi specializing in Next.js, NestJS, e-commerce, and payment integrations. I partner with founders and businesses to launch online stores and websites that rank high and convert, alongside custom business software (POS, ERP, CRM) and seamless payment gateways (M-Pesa, Stripe, cards) that automate cashflow and operations. No agency overhead — just fast code, reliable payment flows, and direct revenue growth.
Websites that sell. Systems that run.
E-Commerce & High-Converting Websites
Fast Next.js storefronts, technical SEO, and sub-second speed that attract traffic, reduce bounce rates, and turn visitors into buyers.
Payment Integrations & Gateways
Frictionless checkout experiences with M-Pesa (STK Push, Daraja API), Stripe, card payments, automated receipts, and multi-currency billing.
Business Systems (POS, ERP, CRM)
NestJS APIs, inventory management, customer records, and operations software that keeps your business running smoothly.
Idea to First Paying Customer
End-to-end product delivery: store architecture, payment flows, customer onboarding, and reliable cloud deployment.
Things I shipped. Live right now.
- 01Nine Hertzmedic.devalentine.comPersonalreact / nestjs / docker
- 02Devaltechdevaltech.co.keBrandnext.js / react
- 03lazyDLPgithub.comPersonalreact / ink tui
- 04Journalingjournauling.devalentine.comPersonalreact native / expo / ai
- 05University Computer Societycomputersocietyofkirinyaga.orgVolunteernext.js / tailwind
- 06Tekoblisstekobliss.comClientreact / branding
From raw idea to paying customers.
Blueprint
Build
Launch
Production systems & impact.
- 01Active
Freelance & Client Systems
Freelance Full-Stack Engineer Direct Client Work
Partnering with businesses to build high-converting Next.js websites and custom NestJS business software (POS, ERP, CRM). Engineered for maximum page speed, Google visibility, M-Pesa payment integration, and converting visitors into paying customers.
- next.js
- nestjs
- pos
- erp
- 02Active
Transcom Media
Full-Stack Engineer & Consultant Client Systems
Architecting custom business websites, automation tools, and content management platforms for corporate clients to streamline operations and enhance digital presence.
- php
- codeigniter
- wordpress
- mysql
- 03Active
University Computer Society
Lead Platform Architect & Vice Chair Product & Growth
Led development of the organization's community platform with NestJS and Next.js, integrating automated M-Pesa payments and member dashboards. Active users grew by 40% under my technical direction.
- next.js
- nestjs
- m-pesa
- community
- 04
Nine Hertz (Clinic Management)
Full-Stack Product Engineer Healthcare SaaS
Engineered a comprehensive clinic management and booking platform handling patient medical records, appointment scheduling, SMS reminders, and operational cashflow insights.
- react
- nestjs
- docker
- postgresql
- View track record