Open to interesting problems
Hi, I'm Douglas Wanjala
Software Engineer, Product Builder & DevOps Engineer. I design and ship scalable backend systems, APIs, and full-stack products — from architecture to production.
About
Software Engineer with a product owner's instincts
I'm a Software Engineer with 8+ years of experience building scalable backend systems, APIs, and digital products across telecom, SaaS, and consumer platforms. I'm proficient in Java, Spring Boot, PHP, Flutter, and PostgreSQL — and beyond my professional roles, I independently architect and ship full-stack products end-to-end, from system design to production operations, combining technical depth with strong product ownership.
- Years of experience
- 8+
- Products shipped end-to-end
- 5
- Core stack
- Java · PHP · Flutter
Skills
Technical toolbox
Languages & Frameworks
Databases
Cloud & DevOps
Architecture
Security
Tools
Experience
Where I've worked
Software Engineer · Safaricom PLC
Mar 2022 – Present- Led development of a Home Fibre Payment Reminder platform, improving billing adherence and reducing customer support volume on account status inquiries.
- Introduced downloadable invoices and payment reminders, boosting accessibility for employer-sponsored billing customers.
- Contributed to Securenet API transformation, enhancing digital channel reliability, performance, and data security.
- Built a 5G router contract eligibility-check platform and supported PTMP deployment for differentiated home internet delivery.
Senior Software Engineer · MwalimuPLUS Ltd
May 2018 – Mar 2022- Designed and implemented backend APIs for web and mobile applications using Yii2 and Laravel.
- Integrated multiple backend systems and databases; managed offline server deployment for low-connectivity environments.
- Diagnosed production issues, resolved defects, and optimized application performance across the full software lifecycle.
Education
B.Sc. Health Records and Information Management
Kenyatta University · Second Class Honors (Upper Division)
2011 – 2015
Kenya Certificate of Secondary Education
Teremi High School · B Plain
2006 – 2009
Projects
Selected product portfolio
- Architected a secure multi-tenant SaaS with RBAC, M-Pesa subscription billing (feature-flagged), and field-level PII encryption via PostgreSQL pgcrypto.
- Integrated a Python AI microservice for task risk scoring, weekly family insights, meal suggestions, and shopping list generation.
- Built a multi-tenant merchant portal with schema-level tenant isolation for payment operations across M-Pesa, Stripe, Airtel Money, and PesaLink.
- Implemented dashboard analytics, team/role permissions, API key onboarding, and AES-encrypted credential storage with TOTP-based 2FA.
- Built a schema-per-tenant SaaS for service businesses (salons, barbershops, car washes) to log jobs, customers, and revenue.
- Implemented tiered M-Pesa STK Push subscription billing (Starter, Business, Pro) targeting Nairobi's informal service sector.
- Developed collaborative shopping lists with multi-store pricing and role-based controls.
- Integrated M-Pesa Daraja; provisioned and secured full production infrastructure.
Retail Intelligence Platform
Price Intelligence
- Built Puppeteer scrapers for Carrefour, Naivas, and Jumia.
- Engineered an LLM-powered ETL pipeline using the Claude API for product normalization and cross-store matching.
Contact
Let's build something together
Have a project in mind, or just want to talk shop? I'm always open to hearing about interesting problems.