Chintan is available for hire
Hire ChintanChintan Patel
Verified Expert in Engineering
Senior iOS Developer
Ahmedabad, Gujarat, India
Toptal member since August 19, 2013
Bio
Chintan is an iOS Developer with 17+ years of experience and has shipped 25 apps with 15 million+ installs combined. Top clients include sovereign wealth funds like PIF Saudi Arabia with $900+ billion in AUM, and leading consumer apps like Cal AI and MyFitnessPal. He has extensive experience in communication, finance, secure crypto wallet apps, and AI-powered apps. He also has considerable Node.js experience, having worked on the Cal AI server and a private app with 1.7 million registered users.
Portfolio
Public Investment Fund
Design Systems, Swift, SwiftUI, Figma, Mobile Development, Design Thinking, iOS...
Cal AI
Swift, SwiftUI, Artificial Intelligence (AI), A/B Testing, Node.js, LangGraph...
SynapX Health
iOS, Large Language Models (LLMs), HealthKit, Apple HealthKit...
Experience
- iOS - 16 years
- Interface Builder - 14 years
- Xcode - 14 years
- UIKit - 14 years
- Swift - 7 years
- Objective-C - 6 years
- Firebase - 4 years
- SwiftUI - 3 years
Preferred Environment
MacOS, GitHub, Git, iOS, Xcode, Swift, Objective-C, UIKit, SwiftUI, Artificial Intelligence (AI)
The most amazing...
...app I developed is Cal AI Calorie Tracker, which became the #1 most downloaded health and fitness app and got acquired by MyFitnessPal for $100 million.
Work Experience
iOS Developer
2025 - PRESENT
Public Investment Fund
- Developed a WhatsApp-like chat interface with features like photo and video drawing, cropping, editing, adding emojis, stickers, etc.
- Created a PDF editor interface to allow annotations on large PDFs of more than 500 MB and 500 pages while keeping RAM consumption and performance of the app stable. Involved heavy performance optimization.
- Developed a Chatbot component for internal enterprise deployment, which allows employees to get quick answers from the corporate knowledge base.
- Developed an employee tracking system which allows managers to respond to employee leave requests, track attendance, work allocation, etc.
Technologies: Design Systems, Swift, SwiftUI, Figma, Mobile Development, Design Thinking, iOS, User Interface (UI), Mobile, Artificial Intelligence (AI), AI Chatbots, PDF, App Design, Apps, App Store, HTML5
Senior iOS Developer
2025 - 2026
Cal AI
- Conceptualized, designed, and developed Wrapped 2025, showcasing users' year in terms of app activity.
- Developed and maintained mission-critical payments systems for both Stripe and Apple In-App Purchase StoreKit Payments for both Individual and Family Plans.
- Developed AI-powered features for CI/CD pipeline, which significantly reduced the time spent on manual processes by the entire development team.
- Acted as the point-of-contact "go-to guy" for all development-related questions from other teams like QA, Business Intelligence, Customer Support, etc.
- Shipped fast without breaking things by having 99.99% crash-free users despite weekly feature-heavy releases.
Technologies: Swift, SwiftUI, Artificial Intelligence (AI), A/B Testing, Node.js, LangGraph, LangChain, LangSmith, Firebase, App Design, Apps, App Store, Stripe
iOS Developer
2024 - 2025
SynapX Health
- Developed MVP for a healthcare app powered by AI for senior citizens.
- Developed iOS app UI using client's Figma designs.
- Gave suggestions to clients about iOS development best practices.
Technologies: iOS, Large Language Models (LLMs), HealthKit, Apple HealthKit, Mobile App Development, Mobile Applications, Back-end Development, Swift, Web Applications, Web Development, HTML, CSS, JavaScript, Node.js, ChatGPT, OpenAI, Firebase, Artificial Intelligence (AI), APIs, Supabase, Software Architecture, Early-stage Startups, Minimum Viable Product (MVP), SwiftUI, ChatGPT API, Async/Await, Model View ViewModel (MVVM), Asynchronous Programming, Networking, User Experience (UX), Prompt Engineering, RESTFul APIs, TypeScript, Realm, Apps, App Store
iOS/Swift Developer
2024 - 2024
Proton
- Took over a project in critical condition from a previous developer and worked hard and fast to improve the project architecture and performance by fixing bugs and implementing Swift/SwiftUI best practices.
- Managed another iOS developer and oversaw his work with code review before integrating it into the main project.
- Converted client's Figma designs to SwiftUI for new features.
Technologies: Swift, iOS, PSD to Swift, Instant Messaging, SwiftUI, Figma, Apple HealthKit, Web Development, Web Applications, HealthKit, CTO, Low-level Programming, Software Architecture, Messaging, Async/Await, Combine, Asynchronous Programming, Networking, Asynchronous Data Streams, Real-time Data, User Experience (UX), Teaching, RESTFul APIs, Optimization, Realm, Apps, App Store
iOS/Swift Developer
2024 - 2024
Freelance Client
- Developed a secure, real-time messaging app for iOS using SwiftUI and XMPP within a tight deadline by taking over work from a previous developer. Rapidly worked on adding new features and fixing existing bugs in the project.
- Converted Figma design mockups provided by the client to an iOS app.
- Assumed a tech lead role by reviewing and merging other developers' code into the main branch.
Technologies: Swift, iOS, PSD to Swift, Instant Messaging, SwiftUI, Encryption, Security, Mobile Architecture, iOS SDK, APIs, Mobile, REST, Mobile App Development, Mobile Development, Web Development, Web Applications, CTO, Software Architecture, Messaging, Minimum Viable Product (MVP), Combine, Asynchronous Programming, Networking, Asynchronous Data Streams, Real-time Data, User Experience (UX), RESTFul APIs, App Store
Senior iOS Developer
2012 - 2024
Freelance
- Developed a patient/doctor encrypted communication app using Parse as a back end. I built both the iOS app and the back end.
- Developed LoveArt, a greeting cards app that became the number one free app overall in Spain and number two in France and Brazil.
- Developed Greets, another greeting cards app that enables users to share custom animated GIFs as greeting cards for various occasions to friends via Facebook, Twitter, and email.
- Built Talking Puppy and Talking Santa, two apps that repeat spoken words in funny voices and allow users to export the audio/video to YouTube or the phone gallery.
- Published an iOS app that reached 1.7 million registered users at its peak. I developed both the iOS app and the back end.
Technologies: Objective-C, Mobile Applications, Architecture, Firebase, Node.js, Geolocation, Google Geocoding API, Geocoding, Mobile Architecture, iOS SDK, RevenueCat, APIs, Mobile, REST, Single Sign-on (SSO), Mobile App Development, Full-stack, Mobile Development, Web Development, Web Applications, Artificial Intelligence (AI), CTO, Supabase, Assembly, Software Architecture, Async/Await, Model View ViewModel (MVVM), Asynchronous Programming, Networking, User Experience (UX), UIKit, Swift, SwiftUI, Prompt Engineering, RESTFul APIs, Optimization, App Store, HTML5
Senior Software Engineer
2010 - 2012
Gateway Technolabs Pvt. Ltd.
- Developed a 3D game for iOS using the SIO2 3D game framework.
- Worked onsite in South Africa for 16 months, creating a text/voice messaging app aiming to replace the need for traditional SMS.
- Developed TouchPoint, a survey management application for large corporations whose clients include the US Army, the US Navy, Amazon, Accenture, Bank of America, and more.
- Developed Sears Catalogs for Sears Canada, enabling users to browse the entire Sears Catalog on iPad.
- Mentored new employees in iOS development by conducting training sessions for iOS development best practices, including how to be productive using Xcode, version control management, etc.
- Developed a citizen journalism app and SDK for Filemobile that enables users to report incidents of interest by capturing audio, video, and text and uploading to a server.
Technologies: Mobile Applications, Architecture, Geolocation, Geocoding, Mobile Architecture, iOS SDK, Mobile, REST, Mobile App Development, Mobile Development, Tutoring, Training, Teaching, RESTFul APIs
Software Engineer
2009 - 2010
Elan Technologies Ltd.
- Estimated the time and cost requirements of iOS apps based on client specifications.
- Developed a wireless file sharing app for iPhone that reached the Top 20 for free business apps on the App Store.
- Built Foursight, an iOS game for 2 players featuring AI logic design for playing against a computer, push notifications for playing over the internet, and Bluetooth support for 2-player local gameplay.
- Conducted training sessions for new employees to train them in various iOS technologies such as Core Data, UIKit, Core Location, etc.
Technologies: Objective-C, Mobile Applications, Geocoding, Mobile, Mobile App Development, Mobile Development, RESTFul APIs
Software Engineer (Trainee)
2008 - 2008
Infosys Technologies Ltd.
- Received training in C language, RDBMS, Java, JSP, HTML, CSS, JavaScript, and more to prepare for a career in the software industry.
- Created a courier tracking system for a courier company involving the use of the Oracle database, JSP, HTML, CSS, and JavaScript.
- Oversaw documentation and code quality checks to make sure they adhere to company guidelines.
Technologies: JavaScript, CSS, HTML, Oracle, Jakarta Server Pages (JSP), Java, RDBMS, Unix, C
Experience
Cal AI
https://calai.app#1 Most Downloaded Health & Fitness app on the App Store.
Leading calorie tracker app acquired by MyFitnessPal for $100 million.
I worked on critical features such as onboarding flow, payment processing (Stripe & StoreKit), food scanning API, family plan feature, A/B testing etc.
Improved app stability by fixing crashes which led to the app having 99.99% crash-free users with 500K DAU.
Leading calorie tracker app acquired by MyFitnessPal for $100 million.
I worked on critical features such as onboarding flow, payment processing (Stripe & StoreKit), food scanning API, family plan feature, A/B testing etc.
Improved app stability by fixing crashes which led to the app having 99.99% crash-free users with 500K DAU.
MyFitnessPal
https://www.myfitnesspal.com#1 Top Grossing Health & Fitness app on the App Store.
Worked on improving performance and stability of the app by fixing obscure edge case crashes.
Worked on converting legacy Objective-C code to modern Swift.
Worked on improving performance and stability of the app by fixing obscure edge case crashes.
Worked on converting legacy Objective-C code to modern Swift.
Call Recorder
https://www.callrecorderfree.comA call recording app for iPhone that allows you to record important calls to listen again later; it is an ideal app for recording phone interviews, lengthy explanations, advice from doctors/lawyers, etc.
I designed and developed the entire app from scratch and was the sole designer/developer who worked on it.
The app is rated on the App Store with a 4.6 stars average and 2,300+ ratings.
I designed and developed the entire app from scratch and was the sole designer/developer who worked on it.
The app is rated on the App Store with a 4.6 stars average and 2,300+ ratings.
Greets
A fun app for sending animated greeting cards for all occasions and the app had custom animated stickers for various greeting occasions such as birthdays, anniversaries, etc. where the user could add his message in an animated GIF. The app would send a request to the server and create a customized GIF with the user's message.
Jukio
An app whose mission is to establish a musical democracy by crowdsourcing party playlists. It has been featured on TechCrunch, BBC radio, etc. The app was based on radio API, a music streaming service, and we added our back-end magic on top of that.
Sears Catalogue
This is an app for the Canadian App Store that allows users to browse the Sears Catalogue on the iPad. The Sears Catalogue is a renowned shopping list promoted by Sears and updated every Christmas. This app allows users to browse the catalog digitally, which was once a physical catalog.
TouchPoint | Business
A B2B application for companies, organizations, and institutions to collect feedback from their customers and employees, where the clients include Fortune 500 companies such as Amazon, Accenture, and Bank of America and government institutions such as the US Army, US Navy, and more.
Vexx SMS
A WhatsApp-like cross-platform voice and text messaging client developed in South Africa, striving to eliminate the need for traditional SMS.
The app was developed on multiple platforms, including iOS, Android, Blackberry, and Windows Mobile. I built the iOS app from start to finish.
The app was developed on multiple platforms, including iOS, Android, Blackberry, and Windows Mobile. I built the iOS app from start to finish.
Foursight
An “easy to learn, hard to master” board game with an original concept. It can be played against the computer or other players. This game had multiple paying modes, including computer, another player online, vs. another player on local wifi, and another player via Bluetooth.
Talking Santa
An entertainment app that mimics phrases said by the user in a funny tone.
This app was similar to Talking Tom where the character repeated whatever the user said in a funny tone. Cool app for both kids and adults to have fun.
This app was similar to Talking Tom where the character repeated whatever the user said in a funny tone. Cool app for both kids and adults to have fun.
LoveArt
A postcards app with uniquely designed original postcards to express love for someone and it ranked the #1 overall free app in Spain and #2 in France and Brazil.
Implemented client's beautifully designed postcards and created an app to match postcards design.
Implemented client's beautifully designed postcards and created an app to match postcards design.
Property Register
An app developed to provide an easy way for real-estate clients to keep track of various property listings and to collect contact information/feedback from visitors in a property show.
Ideal for real estate agents to track client leads during property showcase.
Ideal for real estate agents to track client leads during property showcase.
WiFi HD FREE (Wireless Hard Disk Drive)
https://itunes.apple.com/app/id311170976An app that turns your iOS Device into a wireless pen drive, where it transfers files to/from an iPhone wirelessly over WiFi and ranked in the Top 10 for free business apps in the US App Store.
This project required deep wifi networking knowledge to execute.
This project required deep wifi networking knowledge to execute.
EIE Legal Messaging
An encrypted messaging app with features such as restricting access based on location via geo-fencing, printing conversations, sending photos, videos, audio, stickers, etc.
It is a secure communication app based on Firebase, geolocation, and iOS SDK for communication between small groups like lawyers in law firms, doctors at hospitals, etc.
It is a secure communication app based on Firebase, geolocation, and iOS SDK for communication between small groups like lawyers in law firms, doctors at hospitals, etc.
AskWHS
A ChatGPT-powered app to ask questions about Worker Health & Safety (WHS) for the state of New South Wales in Australia where I was the sole developer in charge of developing the iOS app and the back end based on Node.js and the app used OpenAI API securely using Node.js back-end to stream responses to the iOS app while avoiding exposing the OpenAI API key to the iOS client.
Education
2004 - 2008
Bachelor's Degree in Mechanical Engineering
VVP Engineering College - Rajkot, India
Skills
Libraries/APIs
Parse SDK, iOS Native Libraries, REST APIs, Facebook iOS SDK, X (formerly Twitter) SDK, Google Geocoding API, Firebase iOS SDK, AudioKit, HealthKit, Stripe, RNCryptor, Node.js, Plivo
Tools
Xcode, Instruments, Interface Builder, iOS Simulator, TestFlight, OneSignal, ChatGPT, Geocoding, Apple HealthKit, Git, GitHub, ShowKit, Figma
Languages
Objective-C, Swift, Assembly, TypeScript, HTML5, C, Java, HTML, CSS, JavaScript
Frameworks
Core Location, Cocoa Touch, UIKit, SwiftUI, iOS SDK, AFNetworking, MapKit, Core Data, StoreKit, Combine, Jakarta Server Pages (JSP), Core Bluetooth, LangGraph
Paradigms
Object-oriented Programming (OOP), REST, Mobile Development, Model View ViewModel (MVVM), Asynchronous Programming, Testing, HIPAA Compliance, Functional Programming, Pair Programming, Agile Software Development, Mechanical Design, Design Thinking
Platforms
iOS, Parse, Firebase, RevenueCat, Mixpanel, Mobile, Unix, Oracle, MacOS, Parse Server, LangSmith
Storage
Cloud Firestore, Google Cloud, Realm, RDBMS, SQLite
Industry Expertise
Teaching
Other
AVFoundation, Mobile Applications, Architecture, Instant Messaging, Mobile Architecture, OpenAI GPT-4 API, OpenAI, APIs, Mobile App Development, Full-stack, API Integration, Email, Mobile Apps, Large-scale Projects, Social Networks, Artificial Intelligence (AI), CTO, Supabase, Front-end, User Interface (UI), Software Architecture, Early-stage Startups, Messaging, Minimum Viable Product (MVP), Async/Await, Networking, Subscriptions, A/B Testing, Growth, Asynchronous Data Streams, Concurrency, Data Modeling, Real-time Data, User Experience (UX), Minimum Marketable Product (MMP), Tutoring, Prompt Engineering, Training, RESTFul APIs, Optimization, Design Systems, App Design, Apps, Supabase Auth, App Store, Video Editing, Image Manipulation, Geolocation, Single Sign-on (SSO), iOS Video, Back-end Development, Web Development, Web Applications, Low-level Programming, Payment APIs, Full-stack Development, ChatGPT API, Apple Human Interface, Geolocation Detection, PSD to Swift, Encryption, Security, Mechanical Engineering, Large Language Models (LLMs), Bluetooth, AI Chatbots, PDF, LangChain
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