Full-Stack Developer & Systems Architect · $650K+ on Upwork · Now taking direct projects
Khalil Muhammad
12+ years building systems for the UN, fintech platforms, healthcare APIs, and enterprise SaaS. Clients keep coming back — many off-platform for years.
Companies I've Worked With
- United Nations – view case study
- Guest Supply – view case study
- The ID Register – view case study
- Inveterate – view case study
- Telnyx
- Hanover Research
- Crayon
- CCS
- ZOOMA
About Me
Full-Stack Developer & Systems Architect with 12+ years of experience designing, building, and scaling complex web applications. Expertise in workflow automation, AI-driven products, and deep API integrations across fintech, healthcare, e-commerce, and enterprise platforms.
Proficient in React, Golang, Node.js, Python, JavaScript, and TypeScript — with a strong foundation in system architecture, performance optimisation, and cloud infrastructure.
$650K+ earned on Upwork as a Top Rated freelancer. Clients consistently return for long-term engagements — many continuing off-platform for years. Now taking on select direct partnerships.
Trusted To Build Systems Used By
Global Multinational Organizations
United Nations, enterprise-scale platforms serving users worldwide
Enterprise SaaS Platforms
Shopify apps, ERP systems, and multi-tenant architectures
Fintech & Healthcare Systems
KYC, identity verification, secure API integrations
Tech Stack
C#
10+ yrs
Go
2 yrs
JavaScript
10+ yrs
Node.js
10+ yrs
TypeScript
10+ yrs
React
8+ yrs
Python
4 yrs
AWS
8+ yrs
GCP
3+ yrs
Azure
8+ yrs
SQL / MySQL
10+ yrs
NoSQL / MongoDB
10+ yrs
Docker & K8s
5+ yrs
Proven Results
100%
Data Backlogged to Save Millions
Impact0%
Customer Retention Achieved
Business Value0% → 0%
Conversion Growth
Outcomes$650K+
Earned on Upwork · Top Rated
Track Record30+
Microservices
Architecture99.9%
Zero Downtime
Migration5+
Multi-tenant
System DesignWhat I Help With
Scalable Backend Systems
Design and build high-performance APIs and microservices
Complex Integrations
Stripe, Shopify, Microsoft Graph, healthcare APIs, telecom
AI & Automation
LLM workflows, document processing, AI assistants
Identity & Security
OAuth, Entra ID, Cognito, enterprise authentication
How I Work
Flexible engagement models built around your needs — from a one-off build to a long-term technical partner.
Fixed-Scope Project
Defined deliverables and milestones with a clear estimate up front. Best for well-specified builds, integrations, and launches.
Hourly / Time & Materials
Transparent, flexible billing for evolving scope. Best for ongoing development, iterative product work, and support.
Monthly Retainer
Reserved senior-engineer capacity each month. Best for long-term product partnerships and a dependable technical lead.
What a typical engagement looks like
Scoping call
A free 30-minute call to understand the problem and your goals.
Proposal & plan
A clear plan, timeline, and honest estimate — no surprises.
Build in sprints
Iterative delivery with regular check-ins and working demos.
Handover & support
Documented, production-ready code and ongoing support.
Work Experience
Mar 2023 – Aug 2023
Telnyx
API Engineer
Developed REST API SDK in 6 languages with unit and integration tests for all SDKs.
Jun 2023 – Dec 2023
Hanover Research
Full Stack Developer
Created a PowerPoint add-in for high-quality research & analytics through a subscription model.
Sep 2023 – Mar 2025
Contact Center Specialists
Senior Full Stack Developer
Built APIs and integrations with Facebook, Sinch for VOIP solutions and marketing automation.
Jul 2024 – Feb 2025
Crayon
Full Stack Developer
Developed an application monitoring and improving Cargo Vessel performance.
Oct 2024 – Mar 2025
ZOOMA
Senior Back End Developer
Created an Azure Managed Application for Azure MarketPlace automating ADP-to-Entra ID syncing and on/off-boarding workflows.
Industries I've Worked In
International Organizations
United Nations
E-Commerce & SaaS
Shopify, Inveterate
Fintech & KYC
The ID Register
Hospitality & Supply Chain
Guest Supply
Telecom & VoIP
Telnyx, CCS
Maritime & Logistics
Crayon
Research & Analytics
Hanover Research
AI & Automation
ZOOMA, UN AI
Client Testimonials
"Khalil built our web application which integrates with CRM 2011 and pulls credit reports from third-party APIs from the ground up and did a great job. Good at communicating and collaborating, with a practical sense about how to approach big design challenges and come up with a solution. Very professional — I will absolutely work with Khalil for upcoming projects."
Mahfuz H.
Enterprise Architect · ThoughtCodes LLC
Financial Application · Aug 2020
"Khalil was very responsive and professional. He successfully completed the project on time and we are extremely happy with his work. We would definitely hire him again in the future."
Jeff K.
Project Manager · Hanover Research
PowerPoint Add-in · Sept 2023
"Khalil is awesome. English fantastic and work excellent."
Tim Bloore
CEO · Aussie Retail
Ecommerce Integration · Oct 2021
"Thank you Khalil! Great work as always!"
Jamen Tabesh
Project Manager · MMCHR
HR & Accounting System · May 2021
Frequently Asked Questions
What time zone are you in, and when can we meet?
I'm based in Islamabad, Pakistan (PKT, UTC+5). My hours comfortably overlap European afternoons and US mornings, and I keep flexible time for calls with clients in other zones.
Do you work on a fixed price or hourly?
Both. Fixed-scope projects for well-defined work, and hourly or monthly retainers for ongoing or evolving development. We'll pick whatever fits your project on our first call.
Can you sign an NDA?
Absolutely. I regularly work under NDAs and am happy to sign one before we discuss any sensitive details.
Do you work solo or with a team?
I work hands-on as your lead engineer and architect. For larger builds I can bring in vetted specialists while staying accountable for delivery end to end.
What size of project do you take on?
Anything from a focused integration or automation to a multi-month platform build. If you're not sure it's a fit, book a call and we'll scope it together.
How do we get started?
Book a free 30-minute scoping call. You'll walk away with a clear plan and an honest estimate — no obligation.
Book a Free 30-min Scoping Call
Get In Touch
© 2026 Khalil Muhammad Mirza. All rights reserved.