
Michal Kalis
Verified Expert in Engineering
Software Developer
Prague, Czech Republic
Toptal member since February 22, 2016
Michal is a senior iOS developer with 10+ years of experience in Swift, SwiftUI, and some UIKit. He built Splash Sports (★4.8, 2.2M+ users) and RunYourPool (★4.9) from scratch. He previously led iOS development at Ciphr, an encrypted messenger. He's currently at Česká televize working with Swift 6 concurrency, SwiftUI, and GraphQL. He's using Daily Claude Code across four projects, including CLAUDE.md, rules, sub-agents, skills, hooks, and MCP integrations. Builder: missinghue.com, kozahive.com.
Portfolio
Experience
- iOS - 10 years
- Scrum - 9 years
- Git - 8 years
- Swift - 8 years
- REST - 6 years
- Objective-C - 4 years
- SwiftUI - 3 years
- Claude Code - 1 year
Preferred Environment
Git, Xcode, Figma, Claude Code
The most amazing...
...challenge I've tackled is porting a C/C++ crypto library to iOS and building an encrypted messenger from scratch.
Work Experience
Senior iOS Developer
Ceska Televize
- Used Claude Code daily to ship features faster on ČT sport and ČT24 - live videos, deeplinks, player analytics, iPad layouts, and more.
- Set up Claude Code with a project guide, a script that adds Swift files to Xcode automatically, custom commands, and hooks that run code generation on every edit.
- Suggested UI and UX improvements on screens and features.
- Refactored views using compositions mostly, DRY-ed services and views, and improved network performance.
Senior iOS Engineer
Splash Sports
- Developed two sport-related apps. RunYourPool is a service for hosting and managing sports pools and SplashSport is a platform for organizing sports contests with cash prizes.
- Designed and developed the core application using an MVVM-C architecture.
- Led continuous integration (CI) and continuous delivery (CD) using GitHub Actions and Fastlane.
- Communicated with designers, other platform developers, and stakeholders.
- Prepared the code to implement unit tests, using dependency injection and following SOLID principles.
iOS Developer
Ciphr (via Toptal)
- Developed a secure communication app with encrypted messenger, email, and storage.
- Designed and developed the core application, including networking, persistence, logic, and UI.
- Ported a C and C++ crypto library built for BlackBerry to iOS.
- Integrated the Double Ratchet Algorithm library and other crypto primitives using AES, HKDF, SHA, and more.
- Created audio playback and recording by decoding and encoding OGG files.
- Wrote unit tests for logic and UI parts of code.
- Led Continuous Integration (CI) and Continuous Delivery (CD) using Xcode Server and Fastlane.
- Communicated with designers, other platform developers, and stakeholders.
- Dealt with and resolved threading issues, mostly socket related.
iOS and Node Developer
Autobeacon (via Toptal)
- Drove iOS and back-end development including architectural decisions and implementation.
- Developed the whole app from architecture design to distribution.
- Used multiple technologies for dash cam recording, audio monitoring, location tracking, push notifications, background usage, geofence and iBeacon monitoring, route calculation, and more.
- Communicated with many third party APIs for (e.g.) breathalyzer tests, retrieving iBeacon information, face detection via Clarifai API, speed checking via Google Maps Premium API, or turn-by-turn navigation.
iOS Developer
Westwing (via Toptal)
- Suggested and implemented ways to make one of the screens (Magazine) look more native.
- Added unit tests using fake objects, dependency injection, and asynchronous expectations.
- Designed and implemented preloading of content in the Magazine screen.
- Added custom modal screen transitions.
iOS Developer
The Diary (via Toptal)
- Collaborated to develop a health tracking app helping patients and doctors to communicate with each other.
- Developed new features and changed existing parts of the app.
- Implemented custom collection view layouts and animations.
- Fixed bugs, refactored, tested, and made UX improvements.
- Managed projects under Scrum methodology in a team of seven iOS developers.
iOS Developer
STRV
- Focused on pixel-perfect designs, interactive UI, custom layouts, and animations.
- Analyzed and developed a music app (StereoCast) in a month; later led a team of two other iOS engineers.
- Involved in the whole development process from discussing ideas with clients, discussing UX and UI, programming, testing, and distribution.
- Conducted unit testing.
- Started learning back-end development in Node.js.
iOS Developer
Cleverlance Enterprise Solutions
- Developed iOS applications for Czech, Slovak and German clients.
- Led development of two apps: CEZ ON-LINE and SprachBox Pro.
- Focused keenly on security, as multiple clients were banks.
- Worked on projects using Scrum methodology.
Experience
Hangs - Voice-first Quiz App (WIP)
iOS: SwiftUI, Swift 6, MVVM + service layer; ElevenLabs STT with OpenAI Whisper fallback; StoreKit paywall; Sentry crash reporting; XCTest suite written alongside features
Back end: Python / FastAPI on Fly.io; ChromaDB for semantic search over a question corpus; OpenAI for generation and scoring; pytest suite
CI/CD: fastlane + GitHub Actions, TestFlight distribution via fastlane match
Claude Code setup configured personally: CLAUDE.md with stack-specific rule files, sub-agents for code review and testing, project skills for repeated workflows (deploy, TestFlight release, crash inspection, question verification), PostToolUse hooks running swiftformat / ruff / pytest, MCP integrations (Figma, pencil, context7)
Approach: Claude Code ships better code when it can observe and verify its own work - added Sentry early so it can read real crash reports, wired test runs into hooks, wrote rule files so conventions don't need re-explaining.
Design flow: Figma, Google Stitch, pencil
Ask for TestFlight access.
SplashSports
https://splashsports.comAdditionally, I prepared unit test applications by implementing dependency injection and adhering to SOLID principles, ensuring the high quality and maintainability of our codebase.
Ciphr
I was responsible for porting a proprietary cryptographic library written in C/C++ for BlackBerry to iOS. Afterward, my job was to build the core app and implement the messenger part utilizing cryptographic primitives and protocols from the library. Our team got the app to a production-ready state with a fully functional chat, email, and storage during the engagement, including features like push notifications, file transfers, audio recording and playback, taking photos, contact verification, and more.
All features—heavily focused on security and privacy—needed to be properly designed considering possible edge cases, security risks, and conformance to proprietary protocols.
StereoCast
Feeln
SprachBox Pro
Ripple
Education
Bachelor's Degree in Information Management
College of Information Management and Business Administration - Prague, Czech Republic
Bachelor's Degree in Information Technology
Brno University of Technology - Brno, Czech Republic
Certifications
AI Developer
robot_dreams by Laba
Skills
Libraries/APIs
Alamofire, REST APIs, Camera API, BACtrack Breathalyzer API, Xcode Server, Sockets, Node.js
Tools
Xcode, TestFlight, iTunes Connect, Auto Layout, Adobe Photoshop, Git, Sketch 3, Claude Code, Sublime Text, Sketch, WebView, Jira, Fastlane, Figma, GitHub, Sentry
Languages
Objective-C, Swift, JavaScript, GraphQL, Python, Swift 6
Frameworks
SwiftUI, Core Data, Core Location, Core Motion, UIKit
Platforms
iOS, Keychain, Firebase
Paradigms
Scrum, REST, Behavior-driven Development (BDD), Unit Testing, Dependency Injection, Model View ViewModel (MVVM), Continuous Delivery (CD), Continuous Integration (CI), Model Context Protocol (MCP)
Storage
JSON, Realm
Other
Software Architecture, Push Notifications, IMAP, OAuth, Chromecast, Ogg, iBeacon, Recording, Cryptography, AVFoundation, User, App Groups, MVVM-C, Cursor AI, AI Development, AI Agents, Open-source LLMs, Large Language Models (LLMs), Fine-tuning, Agentic AI, Prompt Engineering, AI-augmented Software Engineering (AIASE), FastAPI, GitHub Actions
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