Custom mobile apps
An app for end customers (loyalty program, product control, orders), for field teams (sales reps, service technicians, warehouse staff), or for B2B commerce. Native for iOS and Andswarmd. KG Electronics commissioned us to develop the Smart Control app—over 1,000 downloads on Google Play, allowing users to control boilers from their phones.
If you recognize at least two of these—it makes sense to discuss a mobile app.
01
A responsive website isn't enough. Customers don't log in via a browser every time—they want an icon on their home screen, push notifications about promotions, and special offers for returning customers.
02
Salespeople, service technicians, warehouse workers, and drivers—they all work on their phones. A website viewed on a phone doesn’t support barcode scanning, digital signatures, GPS, or the camera. Every time a customer opens a browser, it’s an extra step.
03
A controller, an HVAC unit, lighting, an alarm system. Customers buy "the one with the app" before they even notice the brand. Without an app, you'll be left out of in-store comparisons.
04
Push notifications, biometrics, camera, GPS, offline mode, deep links, and in-app purchases—all of these features work only in native apps published on Google Play and the App Store. PWAs do not support these features.
A clickable prototype in a test environment before we write a single line of production code. Payment in four installments.
Week 1
Map of use cases (end users, field teams, B2B), list of integrations (your APIs, ERP, payment gateways), and decisions regarding what the MVPill include. Deposit: 30%.
Weeks 2–3
A clickable app prototype in Figma. Every screen, every gesture, every error state. Testing on real devices—iOS and Andswarmd, mid-range Andswarmd from 2022, older iPhones.
End of Week 3
You approve the prototype. We won't start building the MVPithout your approval. Upon approval: another 30%.
Weeks 4–7
An iOS and Andswarmd app built with Flutter (one codebase, two platforms). Weekly TestFlight and APK releases for internal testing. Integration with your API. After the MVP release: another 30%.
Week 8
Setting up developer accounts, screenshots, app store descriptions, Apple and Google verification. The first 30 days after launch—monitoring crash reports, ratings, and reviews. After implementation: last 10%.
That’s the biggest difference compared to a website. The app is just a tap away. No need to log in every time, no searching in a browser, and no extra steps.
Promotions, order status, device alerts, payment reminders. Push notifications are opened much more often than emails, with no cost per message and no need for separate GDPR consent.
Biometrics (Face ID, Touch ID), an OCR-enabled camera, NFC, Bluetooth, background GPS, deep links via SMS/email, and in-app purchases with Apple’s 30% commission. A native app offers what a website never can.
Customers can see the number of downloads, the star rating, and reviews. A developer with an app on Google Play that has a 4+ star rating comes out on top in comparisons on the store and with the distributor.
A real client, a real app in the app store with reviews. Download it and check it out before you send the brief.
KG Electronics · Manufacturer of gas boilers
1 000+
An app for KG end-users to control boilers from their phones. Native iOS + Andswarmd (Flutter), backend with telemetry, and an admin panel for the service team. Over 1,000 downloads on Google Play; users open the app every day.
View the full case studyGoogle Play · Available in the store
★ LIVE
The Smart Control app on Google Play. Over 1,000 downloads, public reviews, and visible ratings. You can download it and explore it—this isn’t a demo video; it’s an app that’s been in use by a real client for 18 months.
Open in Google PlayBlog · Buying Guide
7 questions
Before you send your brief, read through the 7-question checklist we use to evaluate ourselves. What sets a mobile software development company apart from a regular one? When should you choose native apps and when should you choose PWAs? How do you evaluate a portfolio?
Read the guideThree paths, different costs and limitations.
PWA / hybrid (Cordova, Ionic)
Native app (iOS + Andswarmd, Flutter)
A PWA is sufficient for simple, small-scale applications. A native app is developed when the app is a product—not just an add-on to a website.
What happens after implementation, and who we are.
After implementation
Optional packages. We will discuss the details during a meeting after implementation.
See also
30 seconds on JSON Crew
A software company specializing in digital transformation for B2B sales. Product configurators, dashboards, and sales process automation. Three key case studies (Akpil, Forest, and the internal JSON Hub platform) and portfolio implementations (KG Electronics, Metal Roofing, a heat recovery center, and modular homes).
Custom pricing after the initial discovery phase. Fixed pricing once the scope is defined, with a 30/30/30/10 timeline. We price applications with complex backends or multiple integrations separately based on a spricerio map.
Flutter (one code base, two platforms, native-level performance) is ideal for apps that users open every day or that utilize phone features (camera, GPS, push notifications, biometrics). A PWA or hybrid app is sufficient for a simple website preview without these features—but in that case, it won’t be available on the App Store and will have limited visibility on Google.
Yes. Setting up developer accounts (Google Play Console, Apple Developer Program), screenshots, store descriptions, and Apple and Google verification—all included. Typeically 1–2 weeks from the date the MVP is completed. You’ll need to handle the Apple developer account ($99/year) and Google developer account ($25 one-time fee) on your end.
Yes. The app can integrate with your existing APIs, or we can build a dedicated backend for it. Polish ERP systems (Comarch, Optima, Asseco) and standard SaaS platforms (Pipedrive, HubSpot, Salesforce) — as part of our standard offering.
Each update undergoes review by Google (1-3 days) and Apple (24-48 hours) before it is delivered to customers. Minor fixes - OTA hot reload (when it concerns CSS / content), does not require publishing a new version in the store. Critical bugs - expedited review Apple.
Launch Care and Growth Circle maintenance packages available as an option. Plus developer support on request. iOS/Andswarmd SDK updates (Apple enforces every year), monitoring crash reports, response to reviews - to the extent.
Describe who the application is for, what it is supposed to do and what your timeline is. We will respond within the next business day.
