01
Device companion apps (BLE)
Pairing, control, settings and data sync for your Bluetooth Low Energy device, with reconnection and offline buffering that hold up in real homes and sites.
FIG 01 · IoT App Development
IoT app development for connected devices and wearables
Bluetooth Low Energy companion apps, MQTT pipelines on AWS IoT Core, dashboards, and Apple Watch and Wear OS apps, built alongside your hardware team, who keep the firmware.
See how it works
FIG 02 · Quick answer
What does an IoT app development company do?
An IoT app development company builds the mobile apps, cloud back ends and dashboards that connect physical devices to people. Elgrith builds Bluetooth Low Energy companion apps, MQTT pipelines on AWS IoT Core, Apple Watch and Wear OS apps, and HealthKit or Health Connect integrations, working with your hardware team on firmware.
- Layers we build: app, cloud, dashboard and wearable
- 4
- Projects delivered since 2015
- 1,000+
- Clients across the USA, UK and India
- 250+
- Your code, cloud accounts and device data
- 100%
FIG 03 · Why it matters
Billions of devices. Each one needs an app that works.
From IoT Analytics (Oct 2025), the Bluetooth SIG (May 2026, citing ABI Research) and AWS’s IoT Core developer guide.
01
21.1B
Connected IoT devices by the end of 2025
IoT Analytics expected connected devices to “grow 14% year-over-year to 21.1 billion by the end of 2025”, and estimates they will reach 39 billion in 2030.
Source: IoT Analytics, 28 Oct 2025(opens in a new tab)02
8.1B
Bluetooth devices shipped a year by 2030
The Bluetooth SIG, citing ABI Research, expects Bluetooth devices to reach “over 8.1 billion units shipped annually by 2030”. Many companion apps start with a BLE connection.
Source: Bluetooth SIG blog, 4 May 2026 (citing ABI Research)(opens in a new tab)03
MQTT
Built for constrained devices
AWS describes MQTT as “a lightweight and widely adopted messaging protocol that is designed for constrained devices”. It is our default for device-to-cloud messaging.
Source: AWS IoT Core developer guide, MQTT(opens in a new tab)
FIG 04 · Architecture
How an IoT app works
Most connected products follow one path: the device talks Bluetooth Low Energy to a phone, the phone (or the device itself, over Wi-Fi or cellular) publishes MQTT messages to the cloud, and the cloud feeds apps, dashboards and alerts. Each layer has its own job.
| Layer | What it does | Typical tech | Who builds it |
|---|---|---|---|
| Device and firmware | Senses, acts and talks to the outside world | Microcontroller firmware and BLE GATT services | Your hardware team |
| Local link | Connects the device and the phone | Bluetooth Low Energy (GATT) or NFC | Agreed together: one GATT profile for both teams |
| Mobile app (gateway) | Pairs, controls, buffers offline and forwards data | Swift, Kotlin, Flutter or React Native | Elgrith |
| Cloud messaging | Receives device messages securely at scale | MQTT on AWS IoT Core or Azure IoT Hub | Elgrith |
| Back end and data | Stores readings, runs rules and sends alerts | Time-series database, APIs and a rules engine | Elgrith |
| Dashboards and wearables | Shows people what matters | Web dashboards, Grafana, Apple Watch and Wear OS | Elgrith |
Firmware stays with your hardware team. We agree the interface with them early and test against real devices throughout.
How apps get built, step by step: read our mobile app development processFIG 05 · What you get
IoT apps we build
Companion apps, cloud back ends and dashboards for connected products, from one smart device to a fleet of thousands.
02
Smart home and building apps
Apps and dashboards for thermostats, locks, lighting and sensors, over Wi-Fi, BLE, or Matter and Thread where your hardware supports them.
03
Industrial and asset-tracking dashboards
Live maps, sensor readings and alerts for equipment, assets and environments, with history in a time-series database.
04
Remote patient monitoring
Apps that collect readings from health devices and wearables and share them with care teams, built with the health-data rules in mind.
05
Fleet and logistics
Vehicle, cold-chain and shipment tracking from GPS and sensor data, with alerts and driver apps.
06
Wearable apps
Apple Watch and Wear OS apps with complications, workouts, notifications and HealthKit or Health Connect data.
07
OTA update flows
Firmware update delivery through the app or the cloud, built with your hardware team, with staged rollouts.
08
IoT dashboards
Web dashboards and Grafana boards for device fleets, readings and alerts.
Deliverables
12
deliverables, in writing
Included in every build, written into your fixed quote before work starts.
FIG 06 · Data path
From device to dashboard, step by step
Device, BLE, phone, MQTT, cloud, dashboard. Each step is designed for flaky connections, low batteries and fleets that grow.
- Sensor
- Wearable
- Smart device
- Tracker
Your IoT platform
- Mobile app
- Dashboard
- Alerts
- Data warehouse
1. Provision
- What
- Each device gets its own identity
- How
- X.509 certificates, registered in the cloud
- Why
- One stolen key can’t open the fleet
2. Pair over BLE
- From
- Your device’s GATT services
- To
- The phone app
- Handles
- Bonding, reconnection and permissions
3. Buffer offline
- Where
- On the phone or the device
- When
- No signal, flight mode, basements
- Then
- Synced in order once back online
4. Publish over MQTT
- To
- AWS IoT Core or Azure IoT Hub
- Security
- TLS and per-device policies
- Why
- Lightweight messaging for constrained devices
5. Store and process
- Where
- A time-series database and rules engine
- Does
- Thresholds, alerts and aggregates
- Feeds
- Your warehouse and analytics
6. Show and alert
- Where
- Web dashboards and Grafana
- Alerts
- Push, SMS or email
- Who
- Users, operators and support
7. Update over the air
- What
- Firmware and app updates
- How
- Staged rollouts, with a way back
- With
- Your hardware team
8. On the wrist
- Where
- Apple Watch and Wear OS
- Shows
- Glanceable data and alerts
- Syncs
- With the phone app
FIG 07 · Wearables
Wearable app development
Apps for the watch on someone’s wrist, built for today’s platforms: watchOS and Wear OS.
06principles
Apple Watch and watchOS
Standalone or companion watchOS apps in Swift and SwiftUI, with complications, workouts and notifications.
Wear OS
Wear OS apps in Kotlin with Compose for Wear OS, tiles and data sync with the phone.
HealthKit and Apple’s rules
Health data read and written with the user’s permission. Apple’s guidelines say apps “may not store personal health information in iCloud”, and limit how health data can be used, including for advertising.
Health Connect
On Android, Health Connect is the shared store for health and fitness data, with permissions the user controls.
Phone and watch sync
WatchConnectivity on Apple and the Data Layer on Wear OS, designed for when the phone is out of reach.
Health-data rules
Wearable data used for care can bring HIPAA or UK GDPR into play. Our healthcare app team covers the rules.
Healthcare app development
FIG 08 · Security
Security and updates
Connected devices are a target. We design security and updates in from the first sprint.
06principles
Device certificates
A unique X.509 certificate per device, provisioned at manufacture or on first setup, never a shared key.
Least privilege
Each device can publish and subscribe only to its own topics, enforced by cloud policies.
Signed OTA updates
Updates rolled out in stages and verified on the device by your firmware, with a path back if something fails.
Data retention
Readings kept as long as you need them and no longer, with retention rules per data type.
Revocation
Lost or compromised devices revoked from the cloud in one step.
Fleet monitoring
Connection drops, battery levels and failed updates visible on a dashboard, with alerts.
FIG 09 · Choosing
How to choose an IoT app development company
Questions to ask the IoT app development companies on your list, us included.
06principles
Do they ask for your GATT profile?
A good partner asks how your device exposes data before quoting, not after.
Can they explain offline sync?
Ask what happens when the phone loses signal mid-upload. The answer should be specific.
How do they provision devices?
Per-device certificates, not one shared key baked into every unit.
Do they test with real hardware?
Simulators help, but range, battery and reconnection only show up on real devices.
Who owns the cloud accounts?
Your AWS or Azure account, your certificates and your device data, from day one.
Do they use current names?
Wear OS, not Android Wear. Apple Watch, not iWatch. Outdated names in a proposal are a warning sign.
FIG 10 · Process · 7 steps
Hardware and software, one plan
Your hardware team and ours work from one interface spec. You get a written scope and a fixed quote after discovery, then weekly demos against real devices.
- Step 01
Discovery
Your device, firmware status, users and data. We agree the BLE GATT profile and message formats with your hardware team. You get a written scope and a fixed quote.
- Step 02
Architecture
Device identity, connectivity, cloud and data model designed, including the offline and update paths.
- Step 03
Design
App, dashboard and watch screens designed for pairing, status and alerts that people understand.
- Step 04
Build in sprints
App, cloud and dashboards built in sprints, with weekly demos on real hardware and simulators.
- Step 05
Field testing
Range, battery, reconnection, offline and update tests in the conditions your users live in.
- Step 06
Launch
App store submissions, fleet provisioning and monitoring in place.
- Step 07
Support
OS updates, new devices and new features, on terms agreed in your written scope.
FIG 11 · What you get
Everything included
Written into your fixed quote, so you know exactly what you are paying for before work starts.
12items
- Interface spec agreed with your hardware team
- Written scope and fixed quote
- BLE companion app for iOS and Android
- MQTT messaging on AWS IoT Core or Azure IoT Hub
- Device provisioning and certificates
- Offline buffering and sync
- OTA update flow, with your firmware team
- Web dashboard and alerts
- Apple Watch or Wear OS app, if needed
- Field test report
- Runbooks and monitoring
- Code, cloud accounts and docs, all yours
FIG 12 · Tech & tools
The tools behind the work
Proven, well-supported tools, chosen for your project and set up in accounts your business owns.
- Swift
- SwiftUI
- Kotlin
- Jetpack Compose
- Flutter
- React Native
- Core Bluetooth
- Bluetooth Low Energy
- MQTT 5
- AWS IoT Core
- Azure IoT Hub
- Matter
- HealthKit
- Health Connect
- Node.js
- Python
- PostgreSQL
- Grafana
FIG 13 · Who it’s for
IoT apps for hardware teams and the businesses that run devices.
In the US, the UK and India.
3 audiences
Hardware teams
Your device deserves an app as good as it is.
Consumer and B2B hardware teams with firmware in hand who need the companion app, cloud and dashboards.
- GATT profile agreed early
- iOS and Android companion apps
- Cloud and fleet dashboards
- Firmware stays with your team
Operations
See every asset, sensor and vehicle.
Businesses that run fleets, buildings or equipment and need tracking, alerts and history in one place.
- Asset and fleet tracking
- Sensor alerts
- Time-series history
- Data into your warehouse
Digital health
Wearables and devices for care.
Health teams adding remote monitoring with wearables and connected devices, built with HealthKit, Health Connect and the health-data rules in mind.
- Apple Watch and Wear OS
- HealthKit and Health Connect
- Care-team dashboards
- Built with our healthcare app team
FIG 14 · Working with us from the USA and UK
Built in New Delhi. Run on your hours.
Every project gets a point of contact in New York or London and an engineering team in New Delhi. Here is how today’s working days line up, live.
New York
North America
--:--ET
New Delhi team Your working day- Shared working time
- ≈ 3 hours today
- New Delhi is
- 10.5 h ahead
- Live calls, your time
- 9 a.m. to 12 p.m. ET
London
UK & Europe
--:--UK
New Delhi team Your working day- Shared working time
- ≈ 4.5 hours today
- New Delhi is
- 5.5 h ahead
- Live calls, your time
- 9 a.m. to 1:30 p.m. UK
Three ways to work together
- 01
Fixed-scope project
A written scope, one fixed price and a dated plan. Suits websites, apps and MVPs.
- 02
Dedicated team
Designers and engineers on your roadmap every month, billed monthly.
- 03
White label
For US and UK agencies: our work, your brand, unbranded deliverables.
Every engagement
- Fixed quote in USD, GBP or INR after a free 30-minute call
- NDA before discovery. You own all code, designs and content
- A working demo every sprint, not status slides
- Reply within one business day, calls inside your hours
Book a call
Calls on ET or UK hours
FIG 15 · Choose
Cross-platform or native for an IoT app?
Both work for IoT apps. The device features you need decide it.
| Native (Swift and Kotlin) | Flutter | React Native | |
|---|---|---|---|
| BLE access | Full, through Core Bluetooth and Android’s BLE APIs | Through plugins, with native code where needed | Through libraries, with native modules where needed |
| Watch apps | watchOS and Wear OS, natively | Phone app in Flutter; watch app usually native | Phone app in React Native; watch app usually native |
| Background work | The most control | Native code for edge cases | Native modules for edge cases |
| Codebases | Two: one per platform | One for iOS and Android | One for iOS and Android |
| Best for | Heavy BLE, background sync or watch-first products | Most companion apps | Teams already working in React |
FIG 16 · Definitions
BLE vs MQTT: what’s the difference?
They solve different problems, and most IoT apps use both.
| Bluetooth Low Energy (BLE) | MQTT | |
|---|---|---|
| What it is | A short-range wireless radio standard | A lightweight publish/subscribe messaging protocol |
| Range | Short: a room or a building | Anywhere with an internet connection |
| Connects | Device to phone or gateway | Device or phone to the cloud |
| Typical use | Pairing, setup and live readings nearby | Telemetry, commands and alerts across a fleet |
| In our builds | The phone app talks to your device | The app or device talks to AWS IoT Core or Azure IoT Hub |
FIG 17 · Compare
AWS IoT Core, Azure IoT Hub or your own MQTT broker?
| AWS IoT Core | Azure IoT Hub | Self-hosted MQTT broker | |
|---|---|---|---|
| Fits | Teams on AWS | Teams on Microsoft Azure | Full control or on-premises needs |
| Device identity | X.509 certificates and policies | X.509 certificates or keys, plus device twins | You build and run it |
| Running cost | Pay-as-you-go to AWS | Tiered pricing from Microsoft | Servers you run |
| Ops effort | Low | Low | High |
| Best for | Most new cloud-connected products | Microsoft-centric businesses | Sites that must stay on-premises |
FAQ
Frequently asked questions
Straight answers about IoT App Development with Elgrith.
It depends on the number of device types, the platforms (iOS, Android, web, watch), how much offline and update logic you need, cloud scale, health-data rules and how ready your hardware and firmware are. We don’t publish prices: after a free discovery call you get a written scope and a fixed quote. Cloud fees are paid to AWS or Microsoft.
FIG 18 · Related
Keep exploring
App Development
iOS, Android & cross-platformiOS App Development
Native Swift apps for iPhone & iPadFlutter App Development
One codebase for iOS & AndroidReact Native App Development
Cross-platform apps in React NativeHealthcare App Development
Patient & clinician appsData Engineering
Pipelines, warehouses & AI-ready dataData Visualization
Dashboards, Power BI & TableauCloud & Deployment
Hosting, CI/CD & DevOps
Free 30-minute call
Give your device the app it deserves.
Tell us about your device and where the firmware stands. After a free discovery call you get a written scope, an interface plan for your hardware team and a fixed quote.
Pick a day for your call
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