Rafael Cuevas — Web & mobile apps · Electronic engineer
From the chipto the app.
Web and mobile apps, plus the electronics behind them. I design every layer, from circuit to cloud to screen, so your connected product works as one system.
- years building apps
- 6+
- apps delivered
- 30+
- IoT projects
- 15+
- Next.js
- TypeScript
- iOS
- Android
- Flutter
- Dart
- BLE
- Circuit design
- PID control
- Microcontrollers
- Sensors
- Firebase
- Firestore
- Cloud Functions
- Google Cloud
- SQLite / Drift
- Kotlin
- Swift
- C#
- HealthKit
- Google Fit
- Figma
About
An engineer who reads both the datasheet and the design file.
Before I wrote code for phones or browsers, I wrote it for microcontrollers. I come from electronic engineering, from assembling boards and building robots, and that “whole system” mindset never left me. Today I build web and mobile apps, but my process is still the same: first I understand how the invisible wires connect the frontend, the backend and the devices. I especially enjoy technical challenges where the physical and the digital meet and have to talk to each other.
15+
IoT projects where the app was one piece of the system
- Electronic engineer by training
- Remote, with clients across the Americas
- English & Spanish
How it all connects
Five layers. One person who sees the whole path.
Most connected products fail between layers, not inside them. I work across all five.
L1
Circuits & sensors
Design circuits and control loops (PID) so the device measures and acts with precision.
15+ IoT builds · university roboticsL2
Firmware
Understand the device protocol and its limits (packets, timing, power) so the app asks for data the right way.
Valyant: built on the ring's custom BLE SDKL3
Connectivity
Keep BLE and Wi-Fi links alive in the real world: dropped connections, background limits, retries.
Valyant: auto-reconnect with exponential backoffL4
Backend & cloud
Move data from device to cloud without losing it: offline-first storage, sync rules, real-time streams.
Valyant: SQLite ⇄ Firestore sync in 500-record batchesL5
App & web
Turn raw readings into screens people understand and trust, on iOS, Android and the web.
30+ apps shipped · Pharma B2B on web and mobile
Services
What I build
- What you get
- A mobile app with a BLE layer that reconnects on its own, offline-first storage and a cloud backend.
- Example
- Valyant smart ring
- What you get
- Circuit design, control systems (PID), firmware integration, backend and app, owned by one person. Robotics prototypes included.
- Example
- 15+ IoT projects · university robotics
- What you get
- One production app: layered architecture, security from day one, real-time features, payments and store release.
- Example
- Realay · SSGB · Ubetcha
- What you get
- Web apps that share logic with your mobile app, or fast Next.js sites that search engines can read.
Selected work
Products in the wild
Most client work is private. These are the projects I can show.
How I think
Four rules I follow on every project.
Ideas
Products we could build together.
These aren't past projects. They're ideas that combine things I've already built.
- Possibility
Connected medical devices
Wearables or bedside devices that stream vitals to patients, clinicians and the cloud.
Built on: BLE health data (Valyant)
- Possibility
Remote equipment monitoring
Sensors on machines that report status and alert your team before something fails.
Built on: IoT builds + real-time apps
- Possibility
Fleet & asset telemetry
Trackers and driver apps that show where every vehicle or asset is, and what state it is in.
Built on: Fleet app (TLE) + BLE
Off the clock
Away from the screen.
I still stop to look at how bridges are built. 
My dogs make sure I take breaks. 
Have a product where hardware and software need to talk? Let's build it.
Tell me what you're building and where it gets stuck.