Mario Balug, software architect and product-minded engineer
From idea to production, without the overhead of a full development team.
I design and build custom software, cloud platforms and AI-powered workflows from idea to production. One experienced technical partner, direct communication and no unnecessary layers.
Describe your project
What I can build
Custom software and mobile apps
Internal tools, dashboards, customer portals and workflow systems that replace spreadsheets and manual steps, plus hybrid mobile apps for iOS and Android with the backend behind them.
AI integration and automation
Assistants, search and automation built into the software you already run, connected to your real data and APIs.
Cloud and backend systems
APIs and services that stay fast and understandable as load and team size grow. Databases, messaging, infrastructure.
IoT, edge and industrial integration
Both sides of connected hardware: services on Linux devices that talk to equipment over Modbus and vendor-specific protocols, and the cloud side that manages, monitors and controls the fleet. Works with the cloud you already use.
Speech and AI platforms
Streaming speech-to-text, transcription pipelines and integrations with external AI providers, built for production load.
Architecture and technical consulting
A second opinion or a plan before you commit: architecture reviews, MVP scoping, modernization and hard production bugs.
Projects
A selection of projects I've designed, built and taken to production, from mobile apps and internal tools to industrial edge systems and cloud platforms. Client details are kept confidential; screens are illustrations.
Fleet platform for battery storage
Energy and IoT. The cloud system behind a growing number of battery storage cabinets: it collects their measurements, keeps the history, controls who can see which sites, and lets engineers work on units remotely.
Go, MQTT, NATS, ClickHouse, PostgreSQL
Edge services for industrial equipment
Industrial and edge. Programs on Linux gateways that read and control equipment over Modbus and vendor protocols, hold data while the connection is down, and send it to the cloud platform the customer uses.
Linux, Go, Modbus TCP/RTU, MQTT
Speech-to-text platform
Speech and AI. Dictation for Windows that works in any app: Word, Notepad, a browser. The desktop app streams audio to a backend in the cloud and types the text into the active window about 100 to 200 ms later.
Python, Cloud Run, Cloud Armor, streaming audio
Diagnostics assistant for operators
AI operations. An AI assistant in the operations console. It can only use a fixed set of tools, looks up live data and past cases, opens tickets for the right team, and asks a person before changing anything.
LLM, MCP server, existing APIs, human approval
Mobile app and cloud API for device control
Mobile and connected devices. A cloud API and an iOS and Android app for switching devices, setting schedules and checking energy use at home. Commands go through a hub in the house that talks to lights, heating and locks.
React Native, Expo, Go, Zigbee, Z-Wave, MQTT
Admin console for thousands of users
Business software. An internal tool, similar to a CRM, where administrators manage settings for thousands of users. Sign-in with the company account and a log of every change.
Python, Google Firebase, single sign-on, audit log
Event processing pipelines
Cloud backend. Backend services that take in a constant flow of messages from devices and other systems, process and store them without losing any, and pass them on to customers' systems.
Go, NATS JetStream, GKE, monitoring
Methodology
- Discovery. We define the business problem, who it affects and how success will be measured. I review existing systems and constraints, and confirm whether custom software is the right investment at all.
- Solution design. Architecture, technology choices, security model and a phased delivery plan, set out in a concise written proposal with a realistic estimate for each phase.
- Iterative delivery. Working software from the first weeks, with regular demos and progress updates. Priorities can be adjusted between iterations without renegotiating the whole project.
- Launch and support. Production deployment with monitoring, backups and documentation. After launch: maintenance and further development, or a structured handover to your own team.
About me
I started in 2018 as an embedded Linux engineer, writing C++ for devices. From there I moved up the stack to applications, cloud services and edge devices. After four years of hands-on development I became tech lead of a team of ten, responsible for the main technical decisions across the whole stack. Today I design and build distributed systems as an architect, on my own or with a team, depending on what the project needs.
That path is why I am at home on every layer, from a device on a site to the cloud and the app a customer uses. My background in electrical engineering helps whenever software meets hardware.
Education
- MSc, Electrical Engineering, Faculty of Electrical Engineering and Computer Science (FERI), University of Maribor, Slovenia, 2016 to 2018
- BSc, Electrical Engineering: Automation and Process Computing, Zagreb University of Applied Sciences, Croatia, 2013 to 2016
AI is used where it creates real business value.
AI is one component inside a larger system: connected to your data, limited to what it should touch, and measured against the work it replaces. Sometimes the best recommendation is not to use it.
- Answering questions from your documents, tickets or operational data
- Extracting and classifying information from emails, forms and PDFs
- Assistants inside existing software that can call your own APIs
- Spotting anomalies in telemetry or business metrics
- Speech-to-text for calls, meetings and dictation
- Automating repetitive work your team does by hand every day
Security is part of the design, not a final checklist.
Connected devices, customer data and AI agents all widen the ways a system can be misused. I build with that in mind from the first sketch, using proven tools and simple rules that your team can understand and keep up.
- Access control: Who can see and do what, down to individual sites, devices or records. Multi-tenant from day one when customers share a platform.
- Identity and sign-in: Single sign-on, OIDC and MFA through proven identity providers instead of home-made login code.
- Devices and edge: Each device with its own identity, encrypted connections to the cloud, and remote access that is approved, time-limited and recorded.
- Data protection: Encryption in transit and at rest, secrets kept out of code, and only the personal data you actually need.
- AI with limits: Assistants and agents get the narrowest access that does the job. Read-only by default, with a person approving anything that changes data.
- Visibility: Audit logs, alerts and monitoring that show who did what and when, so incidents are found early and explained quickly.
Tell me about the problem. You don't need to know the solution yet.
Describe what's slow, manual, fragile or missing. I'll reply within two working days with questions or a first idea of how to approach it. Start a conversation
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