Custom websites and
mobile apps, built solo.
Freelance web & mobile developer — working remotely with clients worldwide
One developer, zero handoffs. I design, build, and ship your web or mobile product end-to-end.
I build your product end-to-end, solo.
I'm Mateusz — the developer behind MefjuDev. I build custom websites and mobile apps from scratch: clean code, direct communication, no outsourcing. You work with me from first call to launch.

Three core services.
One developer who ships.
Every project gets a stack chosen for its goals — React, Swift, Flutter, or whatever fits best.
Websites & Web Apps
Landing pages, SaaS dashboards, and e-commerce stores built with React and Next.js — Core Web Vitals passing, Lighthouse 90+.
Native Mobile Apps
Native iOS and Android apps with full hardware access — camera, push notifications, offline storage, and native gesture performance.
Cross-Platform Apps
One codebase running on iOS, Android, and web. Ship faster without sacrificing the native experience your users expect.
Shipped projects across web, iOS, and Android.

LenderBridge.ai
Negotiates with mortgage lenders to prevent foreclosure via short sales.

E-Commerce Store
Handmade wire bouquet store with Stripe checkout and inventory.

PintRadar
Find pint bars nearby, rate them, and connect with beer enthusiasts.

Moums
Find makeup artists, book appointments, and manage payments.

Creator Creator
AI-powered insights to grow your social media audience.
CashFlow
Track income, expenses, and budgets with visual insights.
What clients say after working with me.
Real feedback from real clients on Upwork and Fiverr. 5.0 average across every project.
“Every request was handled professionally, and he went above and beyond to make sure everything worked perfectly. Communication was smooth, delivery was fast, and the final result exceeded my expectations.”
“Mateusz was great to work with throughout the project. Communication was clear, he was responsive to feedback, and delivered the app as requested. He was patient with revisions and always willing to help when questions came up. I'd be happy to work with him again on future projects.”
“So responsive, helpful, understanding and thorough in supporting me through coding and launching my apps on the App Store. Really appreciate it.”
“Thank you for completing the project. I really appreciate the great communication, the frequent updates, and how quickly you handled the bug fixes. It was a pleasure working with you!”
“Delivered above and beyond my expectations — a pleasure to work with!”
From discovery to launch,
in four moves.
Discovery, planning, weekly builds, and launch. You test working software, not mockups.
- STEP 01
Listen First
I start with your business goals, users, and constraints — not code. You get a written scope before any build begins.
- STEP 02
Scope & Plan
We nail down the features, tech stack, and timeline. You know exactly what's being built and how long it'll take — no surprises.
- STEP 03
Build in the Open
Agile sprints with live demos. You get working software to test every week, not a big reveal at the end.
- STEP 04
Launch & Own It
I deploy, test on real devices, and hand everything over. Need ongoing support? I'm here. Want to take it in-house? It's all yours.
Tell me about your project.
Tell me what you're building — the more detail, the better. I'll review your project, reply within 24 hours with my thoughts, and if it's a fit, we'll map out next steps together. No sales calls — just a reply with my thoughts on your project.