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I need a single code-base solution that ships smoothly on iOS, Android, and the Web. The core of the product is a clean, reliable calendar integration that helps users schedule, view, and manage events in real time. Think of it as a lightweight productivity hub: no e-commerce, no social feed—just a focused tool that keeps appointments synchronized across every device. Here’s how I picture the roll-out: • A responsive web app that works in all modern browsers. • Native or near-native mobile builds for iOS and Android, delivered through the usual app-store channels. • Seamless calendar sync (Google, Outlook, iCal) with create, update, delete, and reminder functions. • Secure sign-up and log-in (email, Apple, Google). • Cloud-hosted backend with real-time data updates, minimal latency, and GDPR-ready data handling. Acceptance criteria: — Users can sign in on any platform and see the same events instantly. — Creating or editing an event on one device updates everywhere within seconds. — Push notifications and in-browser alerts fire at the correct times, even if the app is closed. — The interface follows native design guidelines on each platform and passes App Store/Play Store review. I’m open on the stack—Flutter, React Native, or a well-maintained hybrid framework—so long as the calendar features remain snappy and the codebase stays maintainable. Let me know how you would architect the solution, the APIs you’d tap for calendar sync, and a realistic timeline for an MVP followed by polished store releases.
ID do Projeto: 39989528
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185 freelancers estão ofertando em média £4.084 GBP for esse trabalho

With over 8 years of experience designing, creating and integrating highly functional mobile and web apps using a variety of platforms like Flutter, React Native, and hybrid frameworks, I am confident that I have the skills necessary to fulfil your project requirements. One of my standout expertise is in ensuring seamless calendar integration across different devices and platforms and that’s exactly what your project demands. In the past I have built similar productivity apps with features such as event synchronization, creation, updating and deleting of events across multiple interfaces. By leveraging my expansive knowledge in APIs integration such as Google, Outlook, iCal- I can achieve the kind of clean and reliable calendar functionality you are looking for. The fact that client needs are unique fuels my passion to merge flexibility with efficiency- hence why I’m open on the stack but never compromise on performance. Moreover, working across various marketplaces through diverse APIs has enhanced my ability to create solutions that adapt to complex infrastructures; a crucial trait considering how important data reliability is for your project. Having reliable backend support is part of my expertise- from minimal latency to GDPR-ready data handling. Team up with me and I guarantee quality work and timely delivery on each stage of the project’s development cycle.
£4.000 GBP em 7 dias
9,7
9,7

Hi, I am interested in your project. I can help you with everything you're looking for. I have completed over 800 jobs and have a top-rated profile on Freelancer. I would like to have a one-on-one discussion via chat so I can clarify my understanding and workflow for you. Look forward to hearing from you. Thanks Tretanz
£4.500 GBP em 60 dias
9,5
9,5

With over a decade of experience in web and mobile development, I understand your need for a seamless and reliable calendar integration across iOS, Android, and the Web for your productivity app project. The challenge lies in creating a single code-base solution that ensures real-time event management and synchronization on all devices. In the realm of productivity apps, I have successfully delivered tailored solutions that enhance user efficiency and organization. My past projects in this domain have seen significant success, with a focus on intuitive design and seamless functionality. I am confident in architecting a solution that meets your requirements, utilizing a well-maintained hybrid framework like Flutter or React Native to ensure snappy calendar features and maintainable code. For calendar sync, I will tap into reliable APIs for Google, Outlook, and iCal to provide a seamless user experience. I am eager to discuss the specifics of your project and provide you with a realistic timeline for an MVP and subsequent store releases. Feel free to reach out to me to take the next steps towards bringing your productivity app vision to life.
£4.000 GBP em 45 dias
8,9
8,9

Hello , Nice to meet you! I will design and develop EVENT MANAGEMENT mobile application with web admin panel according to your requirement , ping me on chat so we can discuss this more. I am expert and 9 years experienced Android /iPhone app developer with backend work that you are looking for. I will provide you perfect product as you want so you would be happy with it. I am always ready to discuss about your project in detail as well as start from right now. The following are my services that i provide :- 1. Daily or Weekly update. 2. Clean and Robust code. 3. Responsible for communication for more than 15 to 20 hours each day. 4. Free Bug-Fix support for 1 year after completion. 5. Source code delivery. You can have a look at my profile by this link : https://www.freelancer.com/u/shyamvijaywargiy Let's contact me to discuss further details with me. Thanks Shyam
£3.000 GBP em 25 dias
9,0
9,0

Hi, we have read all the requirements and we are very confident to do this project from start till end. We definitely have some questions when we discuss project with you. We shall finish this project in timely manner and will finish it in time. We offer IT, Web design, web development and Smart phone application development. We also give life time guarantee to our work. Thanks
£4.699 GBP em 20 dias
9,2
9,2

With a robust background in building mobile apps and full-stack websites, I bring a wealth of experience to the table that positions me well for developing your productivity app. Having published numerous Android and iOS applications—including ones similar to your project—I’m familiar with the intricacies of app development and have honed my skills to deliver seamless user experiences. I've leveraged APIs for calendar sync on multiple occasions and fully understand the complexity that this aspect holds. As part of my past work, I have created hybrid solutions using both Flutter and React Native, which should make me an ideal candidate regardless of your stack preference. My skills extend across PHP, Mobile App Development (Android and iPhone), React Native, and Web Development, ensuring that I possess the versatility required for your project. Not only do my technical skills align with your needs, but my focus on providing reliable solutions tailored to each client’s specific vision puts me in a unique position to meet your expectations. Having handled secure sign-ups, log-ins, and real-time data handling in the past; I can guarantee GDPR-ready functionality. With all this said, I'm confident in offering you an efficient MVP along with timely releases on all platforms while ensuring minimal data latency and high-level performance on all fronts. Let's work together on making your idea into a sharp reality!
£5.000 GBP em 90 dias
9,3
9,3

Dear Tat M., We carefully studied the description of your project and we can confirm that we understand your needs and are also interested in your project. Our team has the necessary resources to start your project as soon as possible and complete it in a very short time. We are 25 years in this business and our technical specialists have strong experience in PHP, Mobile App Development, iPhone, Android, Web Development, React Native, Flutter, API Development and other technologies relevant to your project. Please, review our profile https://www.freelancer.com/u/tangramua where you can find detailed information about our company, our portfolio, and the client's recent reviews. Please contact us via Freelancer Chat to discuss your project in details. Best regards, Sales department Tangram Canada Inc. P.S. As you see from details of your profile, you located in UK (Great Britain). Be informed that our technical offices located in Ukraine i.e. you will be able work with our developers almost in same time zone.
£4.234 GBP em 5 dias
8,9
8,9

As the leader of a renowned software development company with extensive experience in web and mobile app development, we are well-equipped to build a single code-base solution that meets all your requirements for your productivity app. Our team has profound knowledge in Android and Mobile App Development. We have mastered several cross-platform frameworks like Flutter and React Native, promising you high-quality performance across different platforms. Our expertise extends beyond mere app creation; we understand the importance of a reliable backend infrastructure, and will ensure parallel calendar synchronization across Google, Outlook, and iCal. Given that your focused tool needs minimal latency, our team will design a cloud-hosted backend that handles real-time data updates efficiently while being GDPR compliant. We take pride in clean code structured for maintainability which ensures easy troubleshooting and future scalability. In addition to adhering to native design guidelines for each platform, we'll guarantee speedy App Store/Play Store authorizations. With us on your team, events created or edited on one device will be instantly updated everywhere else
£3.500 GBP em 25 dias
8,5
8,5

Hello and thank you for posting your project. I’ve reviewed the brief for the project which sounds pretty straight forward. I think flutter may be a good option for iOS + Android. However, for web, our tech team may suggest some JavaScript based framework (Angular, React etc). Let’s decide on that when we get into the details of the project. The first step would be to do some discovery calls to go over the scope and document the functional specs of the platform. Once we’re there, we’ll be able to give you an exact estimate for the cost as well and timeline for development. We are a small team of 35-40 young and highly talented web and mobile app developers. Our projects managers will guide you through the planning and development process until the product is fully built and deployed. Please contact via chat and I’d love to discuss further. Cheers! Asad Jahangir CEO, The Coding Company LPC
£10.000 GBP em 90 dias
8,6
8,6

Hi there, Want your cross-platform calendar app to feel fast, consistent, and effortless on every device? I can help build a unified code-base that delivers smooth performance on iOS, Android, and the web while keeping all events perfectly synced in real time. Recently, I worked on productivity tools with live scheduling, reminders, and multi-device sync, ensuring updates appear instantly no matter where they’re made. My focus is always on reliability and clean UX: responsive layouts, intuitive event actions, secure logins, and seamless Google/Outlook/iCal integration. I’d love to bring the same care to your project and craft an app that feels simple, stable, and truly useful. LET’S CONNECT. Many thanks, Saman from Hashone Creatives
£4.000 GBP em 7 dias
9,2
9,2

⭐⭐⭐⭐⭐ Create a Unified Calendar App for iOS, Android, and Web ❇️ Hi My Friend, I hope you are doing well. I reviewed your project requirements and see you are looking for a single code-base solution for a calendar app. You don't need to look any further; Zohaib is here to help you! My team has successfully completed 50+ similar projects for mobile and web applications. I will ensure a smooth roll-out with seamless calendar sync and real-time updates, all within your budget. ➡️ Why Me? I can easily create your calendar app as I have 5 years of experience in mobile and web development. My expertise includes Flutter, React Native, API integration, and real-time data handling. I also have a strong grip on backend development and user authentication, ensuring a reliable and efficient solution. ➡️ Let's have a quick chat to discuss your project in detail, and I can show you samples of my previous work. I look forward to discussing this with you in chat. ➡️ Skills & Experience: ✅ Mobile App Development ✅ Web App Development ✅ Calendar Integration ✅ API Development ✅ Real-Time Data Sync ✅ User Authentication ✅ Cross-Platform Solutions ✅ Cloud Hosting ✅ Push Notifications ✅ Responsive Design ✅ Agile Development ✅ GDPR Compliance Waiting for your response! Best Regards, Zohaib
£3.400 GBP em 2 dias
7,6
7,6

Hello, After 12 years as a full-stack developer, I genuinely believe I am the best fit for your project. I've gained extensive knowledge and experience with every aspect of the app development process that you've outlined, including mobile app development for iOS and Android, using tools such as Flutter and React Native. Moreover, I have In-depth knowledge in calendar synchronization, sign-up/log-in, and creating real-time cloud-hosted backends. I understand the key objectives of your project – to deliver a clean and reliable calendar integration for managing events seamlessly across multiple platforms. To achieve this, I plan to leverage suitable APIs (Google, Outlook, iCal) ensuring smooth event synchronization and robust reminder functions. Additionally, my expertise in hybrid frameworks will ensure a snappy codebase without compromising maintainability. Allow me to transform your app concept into a reality! Let's connect and discuss further how we can proceed with this exciting venture. Thanks Canws
£4.000 GBP em 7 dias
7,4
7,4

Hi, I’m Muhammad Jamshaid, an experienced full-stack developer, and I can deliver your cross-platform scheduling app with a single clean codebase for Web, iOS, and Android. I’ll build a fast and modern UI, real-time event sync, secure login, push notifications, and smooth integrations with Google, Outlook, and iCal calendars. I can outline a clear architecture, timeline, and MVP plan as soon as we begin. Looking forward to collaborating on a polished, store-ready product. Best regards, Muhammad Jamshaid
£4.000 GBP em 7 dias
7,0
7,0

Hello, I am a Mobile App Developer with 15+ years of experience, specializing in building high-quality, user-friendly, and feature-rich applications for both Android and iOS platforms. I create apps with modern UI/UX, smooth performance, and cross-platform compatibility to ensure the best user experience. My expertise includes custom mobile apps, API integration, push notifications, real-time features, and app optimization. Recently, I also worked on OpenAI API integration for auto-generated content, images, and social sharing, which shows my ability to adopt the latest technologies in mobile solutions. If you are looking for a dedicated Mobile App Developer who ensures quality, innovation, and timely delivery, I’d be glad to work on your project. I’m
£3.000 GBP em 7 dias
6,5
6,5

Hello, I will develop your EVENT MANAGEMENT MOBILE APPLICATION for Android and IOS both platforms with Web admin panel. I am Tulsiram. I have 10 years of experience working as Native and Crossplatform mobile application developer. I am understood your requirements. I am glad if we are working together. If you interested then let's connect. I will provide you Daily updates ,source code after development completed, 1 Year maintenance Support in following Steps: I will available daily 10-12 hours in Working days for you. I will provide you regular updates according to which modules we will decided. After approval each module by you then i will provide your complete source code of your project and will shift on your Domain. Thanks
£3.000 GBP em 35 dias
6,6
6,6

Hello there Hope you are doing well as you are looking for a "Build a PRODUCTIVITY MOBILE APPLICATION " so will make the same as you want , I have already develop and Design the so many Application , - I will use latest technology to develop your Application - I will share daily update with you - I Will deliver your project within timeline - After project completion will share complete source code - I will provide 1 year support our develop work - I have 10+ year experience in Web & App development - I will make the 100% responsive design , fast loading , SEO friendly and all - I will provide you super admin panel there you can manage the whole thing Please initiate the chat so will discuss together and all Thanks & Regards Dheeraj K.
£3.000 GBP em 25 dias
7,2
7,2

Hi Tat, I understand you need a unified mobile and web productivity app with seamless calendar integration across iOS, Android, and web platforms. I have experience building cross-platform apps using frameworks like Flutter and React Native, focusing on real-time sync and clean UI following native design norms. I’d implement secure sign-in, real-time backend updates, and use Google, Outlook, and iCal APIs for robust calendar functions that sync events instantly. Let’s discuss the architecture details and your priorities to start shaping a smooth MVP rollout. Thanks, Teo.
£5.000 GBP em 20 dias
6,2
6,2

With a wide skill set that encompasses both web and mobile app development, I can definitely make your app vision a reality. Having 8 years of experience in delivering high-quality projects, I'm confident in my ability to architect a solid single code-base solution for you with Flutter or React Native, ensuring a smooth shipping process for iOS and Android that would pass the App Store/Play Store review. As an AI and ML professional, I understand the importance of real-time data updates and minimal latency in your productivity app. Creating a seamless calendar sync across different platforms (eg. Google, Outlook, iCal) is well within my purview. My experience in using Django, Flask, FastAPI will help in developing secure sign-up and log-in features as well. Being well-versed with cloud-hosted backend and GDPR-ready data handling, I can guarantee the security of user information used in your app. My remote collaboration expertise further assures that even though we may be in different time zones, our teamwork will be seamless and focused towards achieving your desired business growth and innovation. By giving me 详Summ详challenging project like this 详Mobile & Web Productivity App, you wouldn't just ensure a top-notch app delivery but an incredible journey in transforming ideas into extraordinary results. Let's discuss your project in more detail to get started!
£4.000 GBP em 7 dias
6,3
6,3

As an experienced mobile and web developer with a rich background in cross-platform solutions, I am confident that I can architect the exact productivity app you envision. Our team at Gensols Technology has delivered 50+ successful projects specializing in precisely this kind of work. We have expertise with Flutter, React Native, and hybrid frameworks, all of which would suit your requirements perfectly. More importantly, we understand the core of your project - creating a reliable calendar synchronizing tool that users can seamlessly switch between on different platforms. Our API development skills are top-notch and we will ensure integration is as smooth and snappy as you want it. Moreover, we deeply believe in the power of precise and efficient systems. Guaranteeing real-time data updates with minimal delay will be our priority. Backed by our prior experience building productivity-focused solutions for different platforms, we'll craft out a friendly and user-intuitive interface app that mirrors native design guides perfectly—a crucial parameter for App Store/Play Store approvals. Emphasizing on data handling, we make sure that GDPR compliances are strictly adhered to. Trust me to bring my technical expertise together with strategic insight to give form to your unique vision for an efficient and impactful calendar solution. Let’s bring your mobile & web productivity app project to life together!
£4.000 GBP em 7 dias
6,7
6,7

This sounds like something I’d genuinely enjoy building. Your vision of a clean, reliable calendar integration for a lightweight productivity hub resonates with my approach to creating streamlined and intuitive applications. I have a strong track record in delivering polished solutions that ensure seamless synchronization across devices, leveraging technologies like React Native and well-maintained APIs for calendar integration. Happy to outline how I would turn this plan into a working solution. Chat soon, Anne S
£3.500 GBP em 7 dias
6,1
6,1

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