Nixmio is an independent software studio run by Viacheslav, a senior software developer who designs, builds, and launches mobile apps, SaaS platforms, and custom software end to end.

Who builds the apps at Nixmio?

Every project is built directly by Viacheslav. There are no account managers or hidden development teams — you work with the person responsible for the architecture, code, and launch.

What can Nixmio build?

Nixmio builds iOS and Android apps, payment and subscription systems, AI features, booking and business systems, Laravel SaaS backends, and hardware/BLE integrations.

What products has Nixmio launched?

Nixmio has launched Nutrido (AI nutrition tracking), Remidue (a private bill and payment reminder app for iPhone), and App Charts (a live App Store chart tracker for indie developers).

What technologies does Nixmio use?

Nixmio works with Laravel and PHP, Flutter and Dart, native iOS with Swift and SwiftUI, Python and FastAPI, MySQL, and integrations like Stripe and RevenueCat.

Where is Nixmio based?

Nixmio is based in Europe and works with clients worldwide, communicating directly throughout the project.

How do I start a project with Nixmio?

Use the contact form on nixmio.com to describe what you want to build, your stage, and the help you need. Viacheslav replies directly with a practical next step.

Independent software studio by Viacheslav

Build your app with a senior developer, not a faceless agency.

I turn ideas into complete products — mobile apps, payments, AI features, booking systems, and hardware integrations — without you having to manage developers, servers, app stores, or technical decisions. I build production-ready mobile apps, SaaS platforms, and integrations: native iOS and Flutter, API-first Laravel/FastAPI backends, Stripe and RevenueCat billing, AI flows, BLE/IoT, queues, and deployment workflows.

Start a project View products

Top Rated Plus on Upwork 100% Job Success · 8,000+ hours

“Always delivered on time and with great quality. He took care of the entire release process. Will hire again.”

Experienced Flutter mobile developer required

Verified Upwork client · Nov 2021 – Mar 2022

“A true professional! Strong skills in mobile development, top-notch communication, and he met all deadlines.”

Flutter developer (Front-End & API integration)

Verified Upwork client · Mar 2021 – Aug 2022

“A hard-working, trustworthy professional. You can trust it will be delivered on time with the right quality. A top guy!”

Long-term full-time Flutter developer

Verified Upwork client · Dec 2021 – Feb 2025

“Works fast, delivers high quality work, communicates really well and is just a really nice guy.”

Flutter developer long-term

Verified Upwork client · Jan 2022 – Sep 2022

“Always delivered on time and with great quality. He took care of the entire release process. Will hire again.”

Experienced Flutter mobile developer required

Verified Upwork client · Nov 2021 – Mar 2022

“A true professional! Strong skills in mobile development, top-notch communication, and he met all deadlines.”

Flutter developer (Front-End & API integration)

Verified Upwork client · Mar 2021 – Aug 2022

“A hard-working, trustworthy professional. You can trust it will be delivered on time with the right quality. A top guy!”

Long-term full-time Flutter developer

Verified Upwork client · Dec 2021 – Feb 2025

“Works fast, delivers high quality work, communicates really well and is just a really nice guy.”

Flutter developer long-term

Verified Upwork client · Jan 2022 – Sep 2022

About

Built personally. Built properly.

Nixmio is my independent software studio. I'm Viacheslav, a senior software developer focused on building apps, SaaS products, and digital platforms with clean architecture, thoughtful UX, and long-term maintainability. Nixmio is a one-person studio shipping production software: Laravel SaaS, native iOS, and Flutter — with typed backends, tested critical paths, and deployment workflows I maintain personally.

Unlike a traditional agency, you do not get passed between sales people, project managers, and unknown developers. You work directly with me — the person responsible for the architecture, code, quality, and launch. Direct ownership means no telephone game on requirements: I handle architecture, implementation, code review, and release — optionally pulling in trusted specialists when it clearly helps.

For selected projects, I may involve trusted specialists when it makes sense, but the product ownership and communication stay direct. When specialists join (design, QA, DevOps), integration points and delivery still run through me so the codebase stays coherent.

At a glance

Senior software developer
Mobile apps, SaaS & backends
Payments, SoftPOS & subscriptions
AI features & hardware/BLE
Laravel, Flutter, iOS, Python
Europe-based, worldwide clients

Products

Products by Nixmio.

Apps and digital products designed, built, and launched independently by Viacheslav. Shipped products across mobile (Flutter, SwiftUI) and Laravel SaaS — each with its own brand, store listing, or subdomain.

Real products, built with the same care I bring to client work. Nutrido, Remidue, and App Charts are production codebases I own end-to-end — architecture through launch.

Live

Nutrido

AI-powered nutrition tracking with a simple photo-first experience. Flutter mobile app with on-device and cloud meal analysis, macro tracking, and optional account sync.

Dedicated brand: nutrido.io

View product

Live

Remidue

A calm bill and payment reminder app for iPhone — no accounts, no tracking, your data stays on your device. Native SwiftUI iOS app with local notifications, offline-first storage, and RevenueCat for optional one-time full-access purchase.

Dedicated landing page: remidue.nixmio.com

View product

Live

Fotom

A simple loyalty card wallet for iPhone — keep every reward and store card in one place, ready at checkout even offline. Native iOS app with barcode scanning, offline-first storage, optional secure cloud sync, family sharing, and subscription full access.

Dedicated landing page: fotom.nixmio.com

View product

Live

App Charts

See where your iOS app ranks in Apple's public App Store charts — by country, chart type, and movement over time. Laravel SaaS on a dedicated subdomain: hourly Apple RSS Marketing Tools sync, honest rank labelling, global coverage scoring, and admin feed monitoring.

Dedicated SaaS: appcharts.nixmio.com

View product

View all products

Services

How I can help.

From a first idea to a launched product — here are the main things I can build and run for you, end to end. Full-lifecycle delivery across mobile, payments, AI, backend, hardware, and infrastructure — architected, implemented, and deployed by one senior engineer.

Mobile apps — iOS & Android

I build polished mobile apps for iPhone and Android — fast, easy to use, and ready for the App Store and Google Play. Native iOS (Swift, SwiftUI, SwiftData, widgets, notifications) and Flutter cross-platform apps with clean architecture, state management, offline-first data, and store-ready release setup.
Payments, checkout & SoftPOS

I set up the parts that let you charge customers — online checkout, subscriptions, in-app purchases, and Tap to Pay on phones. Stripe Checkout/PaymentIntents, Stripe Terminal, SoftPOS/Tap to Pay, RevenueCat subscriptions, webhook reconciliation, receipts, and idempotent fulfillment.
AI features & automation

I add practical AI to your product — photo analysis, smart extraction, summaries, and assistants that save real time. AI image understanding, document/data extraction, content generation, and usage-limited AI endpoints with human-review flows, caching, and audit logs.
Booking & business systems

I build the systems your business runs on — bookings, events, ticketing, customer records, and admin dashboards. Reservation/availability logic, event ticketing, QR check-in, role-based admin panels, reporting, and CRM-style internal tooling on Laravel.
Backend & SaaS platforms

I build web platforms where users sign up, pay, manage their account, and use your product online. Laravel 13 / PHP 8.4 and FastAPI backends: authentication, billing, roles, REST APIs, queues, scheduled jobs, webhooks, and admin tooling with tests on critical paths.
Hardware, BLE & IoT

I connect apps to physical devices — sensors, readers, and custom hardware — with dashboards to monitor them. BLE scanning, custom GATT services/characteristics, Raspberry Pi gateways, Python device services, telemetry ingestion, and device-status dashboards.
Cloud, hosting & deployment

I put your product online and keep it running reliably — servers, domains, security, and backups handled. VPS setup, Nginx, CloudPanel, DNS/SSL, deploy scripts, migrations, queue/cron workers, logging, and backups for maintainable production environments.

What I can build

What I can build for you.

Concrete products I can deliver end to end. If yours is not listed, the same building blocks usually apply. Reference solution scopes assembled from the same building blocks — mobile, payments, AI, hardware, and backend — delivered to production.

Booking & reservation system

Let customers book slots online, pay upfront, and get reminders — with a dashboard for you to manage it all. Calendar availability, online payments, reminder notifications, staff dashboard, invoices, and admin reporting.
Event & ticketing platform

Sell tickets, take payments, and check guests in at the door — all from one platform you control. Event listings, Stripe ticket payments, QR check-in, confirmation emails, refunds/cancellations, and an admin panel with reports.
SoftPOS / Tap-to-Pay app

Accept card payments directly on a phone — no extra terminal hardware needed. Android Tap to Pay via Stripe Terminal, backend PaymentIntents, receipts, transaction logs, device diagnostics, and a QR/payment-link fallback.
AI photo-analysis app

Point the camera at something and get instant, structured results your users can review and correct. Mobile photo capture, AI image analysis, structured result review with confidence display, history, stats, subscriptions, and a cloud backend.
Subscription SaaS dashboard

A web product with accounts, paid plans, and the dashboards your users and your team rely on. Accounts, plans, Stripe billing, usage limits, team permissions, scheduled imports, analytics, and reporting dashboards.
Loyalty & customer app

Reward repeat customers with a branded app — offers, QR loyalty, and push notifications. Mobile app with QR loyalty, customer profiles, push notifications, offers, payment integration, and an admin dashboard.
BLE hardware controller

A mobile app that connects to and controls your physical device, with a dashboard to monitor it. Mobile BLE app, custom characteristics, Raspberry Pi gateway, firmware protocol docs, telemetry backend, and a device dashboard.
Internal automation tool

Turn a slow, manual process into an internal tool that runs the busywork for you. Admin dashboards, integrations, file processing, AI summaries, scheduled tasks, and notification workers.

Describe what you need

Why Nixmio

Why work directly with Viacheslav?

Direct communication

You speak directly with the person building your product. No account managers — requirements and decisions go straight to the engineer shipping the code.

Personal ownership

No handoffs, no unclear responsibility, no hidden layers. One owner for architecture, implementation, and production issues — easier to debug and iterate.

Senior-level execution

Architecture, UX, performance, and maintainability are considered from the beginning. Validation, authorization, caching, queues, and tests on critical paths — not bolted on after launch.

Product thinking

I help you make practical decisions around scope, launch, pricing, payments, analytics, and long-term growth. Scope cuts, integration choices (Stripe, RevenueCat, Apple RSS), and observability planned before the first deploy.

Clean architecture

Your product should be easy to maintain, extend, and hand off. Laravel-native structure: Form Requests, Policies, Services, config-driven products — readable for the next developer.

Launch focus

The goal is not just to write code — the goal is to ship a real product. Store listings, DNS, migrations, asset builds, and smoke tests included in the definition of done.

Client reviews

Trusted by clients on Upwork.

Top Rated Plus · Senior Flutter Developer · Full Stack

Years of full-time and contract work delivered through Upwork — consistently five-star, with a 100% job success score across every project.

Job Success: 100%
Hours worked: 8,000+
Average rating: 5.0
Mobile development: 8+ yrs

View Upwork profile

“Slava did a great job on our Android and iOS Apps. He understood the requirements, always delivered on time and with great quality. He took care of the entire release process so we had nothing to do except ask for more features. He is a great professional to work with and comes highly recommended. Will hire again.”

Experienced Flutter mobile developer required

Verified Upwork client · Nov 2021 – Mar 2022

Reliable
Committed to Quality
Clear Communicator
Professional

“Slava is a true professional! He delivered good work on our EdTech Flutter app and I enjoyed working with him. He has strong hard skills in mobile app development and his communication was top-notch, he met all deadlines. I really enjoyed working with Slava and will definitely have additional jobs for him in the future.”

Flutter developer (Front-End & API integration)

Verified Upwork client · Mar 2021 – Aug 2022

Professional
Clear Communicator
Reliable
Collaborative

“A hard-working, trustworthy professional and overall a very nice colleague. Slava is the type of person with whom you can discuss ideas and, after agreeing on requirements, you can trust that what was discussed will be delivered on time with the right quality. Most work has been Flutter-based, but Slava never hesitates digging into other parts of the software stack and handling release processes. He single-handedly designed and implemented three Flutter MVP apps from scratch, surpassing expectations in functionality, design, and speed. He's genuinely a top guy!”

Long-term full-time Flutter developer

Verified Upwork client · Dec 2021 – Feb 2025

Trustworthy
Full Stack
MVP from scratch
Top guy

“Slava works fast, delivers high quality work, communicates really well and is just a really nice guy. We wish him all the best!”

Flutter developer long-term

Verified Upwork client · Jan 2022 – Sep 2022

Clear Communicator
Committed to Quality

“Slava did a great job on our Android and iOS Apps. He understood the requirements, always delivered on time and with great quality. He took care of the entire release process so we had nothing to do except ask for more features. He is a great professional to work with and comes highly recommended. Will hire again.”

Experienced Flutter mobile developer required

Verified Upwork client · Nov 2021 – Mar 2022

Reliable
Committed to Quality
Clear Communicator
Professional

“Slava is a true professional! He delivered good work on our EdTech Flutter app and I enjoyed working with him. He has strong hard skills in mobile app development and his communication was top-notch, he met all deadlines. I really enjoyed working with Slava and will definitely have additional jobs for him in the future.”

Flutter developer (Front-End & API integration)

Verified Upwork client · Mar 2021 – Aug 2022

Professional
Clear Communicator
Reliable
Collaborative

“A hard-working, trustworthy professional and overall a very nice colleague. Slava is the type of person with whom you can discuss ideas and, after agreeing on requirements, you can trust that what was discussed will be delivered on time with the right quality. Most work has been Flutter-based, but Slava never hesitates digging into other parts of the software stack and handling release processes. He single-handedly designed and implemented three Flutter MVP apps from scratch, surpassing expectations in functionality, design, and speed. He's genuinely a top guy!”

Long-term full-time Flutter developer

Verified Upwork client · Dec 2021 – Feb 2025

Trustworthy
Full Stack
MVP from scratch
Top guy

“Slava works fast, delivers high quality work, communicates really well and is just a really nice guy. We wish him all the best!”

Flutter developer long-term

Verified Upwork client · Jan 2022 – Sep 2022

Clear Communicator
Committed to Quality

Reviews shown verbatim from Upwork. Hover to pause.

Process

From idea to launch.

STEP 01
Understand the product

We start with what you are trying to build, who it is for, and what success looks like. Discovery on domain, users, constraints, and risks. Define non-functional requirements early.
STEP 02
Define the scope

We decide what to ship first and what can wait — so you launch sooner without cutting corners. Scope shaping, MVP cut, dependency mapping, sequencing, and clear acceptance criteria.
STEP 03
Plan the architecture

I design how the product is built so it stays simple, reliable, and ready to grow. Domain model, API contracts, data layer, queue boundaries, environments, and a deployment topology.
STEP 04
Build the product

I build the product in clear steps so you can see real progress, not just code. Iterative delivery with typed code, validated input, authorized actions, and tests on critical paths.
STEP 05
Test and polish

Before launch, we make sure the product feels right and works reliably for real users. Automated and manual QA, accessibility checks, performance budgets, observability, and security review.
STEP 06
Launch and improve

We ship the product and keep improving it based on what real users do, not assumptions. Production deployment, error monitoring, analytics events, release workflow, and a clear backlog for follow-up.

Work

Selected work and product experience.

Some work cannot be shown publicly, but the experience behind Nixmio includes mobile apps, SaaS platforms, backend systems, admin dashboards, payment flows, subscriptions, app store launches, and product improvements. Representative stack: Laravel 13, PHP 8.4, Flutter, SwiftUI, MySQL, queues, Stripe/RevenueCat, App Store Connect, and CloudPanel VPS deployments.

iOS · Android · AI