An Ultimate Guide to Mobile App Development in 2024

An Ultimate Guide to Mobile App Development in 2024

Do you run a startup or a business? Have you ever considered developing a mobile application for your business? Worldwide, people are mainly investing in mobile applications to empower their business online. Earlier, the mobile application trend was at a very low stake, and it took lots of investment, which made people hesitate to create applications for their business. 

However, since the growth of the IT department, the mobile application has become an asset of any business or industry to the market value and increased customer retention of their service. With time, mobile applications have been evolving rapidly and providing exclusive benefits along with a smooth user experience. 

Although it's pretty impossible to create a mobile application without a professional Mobile app development company. Additionally, it is also essential for the investor to understand the role of mobile app development companies and how they can benefit your business via online apps. So, in this guide, you will find out all aspects of mobile app development and the benefits and market growth in the past decades. 

Need For Mobile Applications 

Mobile applications have become a necessity for almost every digital business. From normal startups to top IT companies, everyone is highly reliant on mobile applications to expand their business and bring customer attention to their platform. Mobile apps offer unparalleled accessibility, allowing users to access information, services, and entertainment anytime, anywhere. It serves as an efficient source for businesses to enhance customer engagement and provide a seamless platform for transactions, support, and communication.

Moreover, mobile apps facilitate personalized experiences, integrating content and functionality to individual preferences. The accessibility and ease of use offered by mobile apps also streamline internal processes, enhancing overall operational efficiency. In essence, a well-crafted mobile app is not just a technological accessory but a powerful catalyst for business empowerment, driving innovation, and ensuring competitiveness in the modern marketplace. 

With intuitive interfaces and interactive dashboards, investors can monitor market trends, analyze stock performances, and receive instant notifications, fostering agility in response to market changes. Moreover, mobile apps facilitate seamless communication and collaboration among investors and business stakeholders. In essence, mobile apps have transcended mere conveniences to become integral components of our daily lives, fostering connectivity, productivity, and entertainment on a global scale.

Market Growth & Demand for Mobile Applications 

Mobile App Development

The mobile applications market has been rapidly growing over the past few decades. As per the current stats, the global market size of Mobile app development services is valued at around  $197.2 billion in 2021. However, the exponential growth stats are recorded at the 12.8% CAGR. It is expected that in the upcoming years, the growth percentage will rise from 16% to 17% in 2024. The mobile app market will cost more than $583.03 billion by the end of the year 2030.

What Difference Does Mobile App Make in B2B Services 

 Mobile App Development

Mobile applications are transforming B2B services by providing unparalleled accessibility and functionality. With the help of a mobile application, it is very easy for investors to access their B2B service through an online portal. With mobile apps development trends, B2B services gain the agility to adapt to evolving market demands, facilitating quicker decision-making and efficient resource management. 

Furthermore, these applications empower businesses to deliver personalized solutions, optimizing user experiences and ultimately cultivating stronger, more dynamic relationships between B2B service providers and their clients.

What is an Average Costing of Mobile App Development 

The most common question that every investor asks is the cost of a mobile app development. However, it completely depends on business to business and the complexity and design of the app. On average, if you consider a basic app for standard business, then it will cost around $10,000-$50,000. However, a simple application for a startup with few services might even cost less than $10,000. So, the cost of an app is not fixed, but it varies around the demand of the customers and the structure of the app. 

For example, a complex application like Instagram or Twitter might cost you more than $100,000. At the same time, a simple dating app can cost you around $30,000-$40,000. Therefore, clients must optimize their plans and the features in the app to reduce the cost and optimize the best app as per the customers' and the client's needs. So think wisely and invest in the perfect requirements of the customers so that you can develop a professional app within your budget.

Mobile App Development

Major Categories of Mobile Applications 

As of now, there are multiple variations of mobile applications and categories. So, let's get a brief idea about the top categories and the mobile applications that are present in the global marketplace. 

Gaming Applications:

Mobile App Development

Gaming applications are digital experiences designed for entertainment and user engagement to play with various electronic devices such as smartphones, computers, or gaming consoles. Gaming is one of the biggest categories in  Mobile app development. 

Game developers employ programming languages and graphics technologies to create interactive and visually appealing environments that captivate players. Moreover there are multiple social connectivity games or people call them multiplayer and online games that allow users to play with friends and knowns worldwide. 

The gaming industry continues to evolve as an exponential market for developers and providing users with a rich and ever-expanding universe of interactive entertainment. Overall, gaming applications serve as a popular and dynamic form of entertainment, offering users an interactive escape into virtual worlds.

Lifestyle Applications:

 Mobile App Development

Lifestyle applications improvise the users' everyday needs, enhancing their daily routines and personal experiences. There are numerous applications from fitness trackers and nutrition apps to habit-building tools and personal organisers. These applications fulfil all the needs of an individual. For example, a fitness app helps users to keep track of their workout routines, health monitoring, and goal-setting features, encouraging users to maintain an active and healthy lifestyle. 

In essence, lifestyle applications serve as digital companions, empowering users to make informed choices and cultivate positive habits in today's fast-paced world. 

Entertainment-focused lifestyle apps provide a platform for relaxation, offering personalised content such as music, movies, or reading recommendations. With the increasing integration of technology into daily life it has become easier for people to keep track of their lifestyle by organizing, and enriching various aspects of users' day-to-day activities. 

Education Applications:

 Mobile App Development

Educational industries are rapidly boosting the marketplace with the latest mobile applications that not only help the people getting education but also set up a good market trend. In the 20th century, the learning style of students has changed with the advanced machine learning and educational apps. With a user-friendly interface, it provides access to a diverse range of educational content that includes interactive lessons, quizzes, and multimedia resources. With features such as progress tracking and performance analytics, students can monitor their growth, and educators can monitor their teaching methods accordingly. 

Furthermore, many education apps incorporate collaborative tools, enabling students to engage in virtual discussions and group projects. In addition to formal academic content,  some applications also offer skill-building modules and extracurricular resources, contributing to a holistic educational experience. Overall, education apps development services are modernizing and democratizing access to quality learning resources, transcending traditional classroom boundaries.

Features such as progress tracking and performance analytics enable both students and educators to monitor and assess academic growth. Nowadays educational apps are not limited to a certain tool or gadget but now they are available on every platform. The professional Mobile developers of educational apps created an advanced platform where people can receive knowledge and select their course accordingly. Additionally, these applications are available for both android and iOS. So it is very convenient to get education from the best platform in the competitive market. 

 Entertainment Applications:

Mobile App Development

Entertainment apps became a necessity in the digital world. An entertainment application is a digital platform designed to provide users with a wide range of engaging content for enjoyment. As per the market states 70% of people use entertainment apps on a daily basis to spend their time with their family and enjoy the moment, watching movies, theatre and shows. There is no doubt that entertainment apps hold a massive customer engagement and become an asset in the mobile app development industry. It is very hard to compete with the leading brands, but if you develop a professional app for an entertainment category, then there is a higher chance of improving its market value and improvising like a brand. 

Entertainment applications offer a wide range of entertainment options including streaming movies, TV shows, music, and games. Beside paid apps investors are also focusing on developing mod applications where people can watch unlimited entertainment for free. Although these applications do not generate a lot of revenue, they can allow other ads and promotional banners on the app which will automatically generate revenue. Whether it's binge-watching a series, discovering new music, or playing interactive games, entertainment applications play a pivotal role in delivering a customized and immersive leisure experience for users across the globe.

Healthcare Applications:

 Mobile App Development

Healthcare applications are improving the experience of users via providing the best valuable service in the segment. Earlier patients have to rely on medical facilities or ambulances to give Care and treatment but it’s not the same with advanced technology. These applications provide a platform for healthcare providers to streamline their operations, from appointment scheduling and patient records management to billing and insurance processing. It not only improves the administrative efficiency of healthcare organisations but also contributes to better patient experiences.

Moreover, the advanced healthcare facilities involve lots of features where people can use quick medication options to receive treatment at the spot. In addition, it is very easy and convenient to book the ambulance or book the doctor on the healthcare app with the user's own preference. It provides convenience to the patient to select the perfect doctor for their treatment and understand the treatment with right communication with the healthcare facility.  Moreover, healthcare apps also help users to save their data and communicate with them in private using the chat or video call options.

As the healthcare industry continues to embrace digital transformation these applications become core of Healthcare businesses seeking opportunities. Find the best healthcare mobile app development company to optimise your service and healthcare facility. 

Finance Applications:

Mobile App Development

A Finance Application is revolutionising the perspective of individuals in managing their finance and accommodation. Generally, it serves as a centralized platform for managing financial transactions, providing businesses with real-time insights into their financial health. With the help of financial applications, users can manage their data and other accommodations to keep track of the investment and expenditure. However, gram multiple categories in the financial app that helps users to manage their transactions and cash flow.

A Finance Application enhances collaboration within the organization by providing a unified platform for financial communication and approvals. As Overall, the adoption of a Finance Application is imperative for businesses seeking to optimize their financial operations, improve decision-making, and maintain regulatory compliance in an increasingly dynamic and competitive market.

Social Media Applications:

Mobile App Development

Social media applications are crucial for businesses from various perspectives. Firstly, these platforms serve as powerful tools for brand building and awareness. Through regular and engaging posts, businesses can connect with their target audience, showcase their products or services, and establish a distinct brand identity. This visibility on social media contributes to increased recognition and trust among potential customers.

Secondly, social media applications offer a direct channel for customer engagement. Moreover, these platforms provide valuable insights into consumer preferences and behaviours, enabling businesses to monitor their strategies to meet market demands effectively. Additionally, the viral nature of content on social platforms can lead to rapid and widespread promotion of products or services. In summary, a strategic presence on social media is essential for businesses to enhance brand presence, engage with customers, gather insights, and execute effective marketing campaigns.

Dating Applications:

 Mobile App Development

In the digital world, dating applications hold immense significance from a business perspective. The dating application market has experienced remarkable growth from a business perspective in recent years. The increasing prevalence of smartphones, coupled with changing social dynamics and a growing acceptance of online dating, has fueled the expansion of this industry. With the convenience and accessibility offered by dating apps, user engagement has surged, resulting in a substantial increase in the user base.

Entrepreneurs and investors have recognized the lucrative potential of the dating app market, leading to a proliferation of new entrants and innovations. The subscription-based model and in-app purchases contribute significantly to revenue streams, while advanced matchmaking algorithms and personalized user experiences enhance customer retention. The business landscape is evolving with niche dating apps catering to specific demographics and interests, fostering diversity within the market. As the demand for digital connections continues to rise, the dating application sector is poised for sustained growth, offering ample opportunities for businesses to thrive in this dynamic and evolving space.

Moreover, dating applications provide a platform for innovative business models, such as premium subscriptions, in-app purchases, and targeted advertising. This diverse revenue stream potential enhances the sustainability and profitability of dating app ventures. Furthermore, these apps can leverage advanced algorithms and data analytics to offer personalized experiences, fostering user engagement and loyalty. As society becomes more digitally interconnected, investing in a well-designed and user-friendly dating application can yield not only financial success but also contribute to the evolution of social dynamics in the digital age

Automotive Applications:

 Mobile App Development

Automotive applications are successfully growing after the digitization of automobile service and the demand of customers to provide convenient service. Some of the top automobile applications are related to the car rental, car wash and car accessory business. These are some of the major categories in automobile applications that are taking over the billion-dollar market.

Automobile applications have become a necessity for customers to manage the service with convenient processes through our mobile application. For example, if a customer wants to get their car washed, then with the help of a mobile application, they can easily book the Car washing service and get accessible services. However, in a personal case, if the customer visits the car wash centre, then it will cost them lots of time and investment with additional services. But it won't be worth the time and investment if the customer provides their service with the help of a mobile application.

Similarly, Top car rental applications are also in great demand as it becomes convenient for the customer to migrate anywhere from their current destination with the help of a car booking service. The automobile industry is captivating the demand of customers, and worldwide, there are thousands of mobile applications in the automobile category.

Some of the Popular Mobile Applications 

Let's explore some popular mobile applications that are trending on the world's platforms and worth more than millions of dollars. Also understand the styling of the applications that are producing billions of revenue for the company. 


 Mobile App Development

TikTok is a worldwide famous and #1 trending social media platform where people can share their reels and videos. The TikTok came from China by the owner ByteDance. Since its release in September 2016, the app has faced multiple controversies and has been banned from multiple countries due to the privacy policy of the company. However, even after so many disastrous bans, the app is still leading in major countries like the US and China and is worth billions of dollars. Additionally, it features multiple celebrities and social media influencers who ultimately increase the net worth of the app and the revenue for the company. Therefore, TikTok is one of the best creations by the Mobile app development company. 


Mobile App Development

Instagram serves as a dynamic social media platform where individuals and businesses connect through visual content like photos and short videos. It allows users to share moments, express creativity, and engage with other people on a global platform. Additionally, Instagram possesses multiple features such as Stories, Reels, and IGTV, providing diverse ways for users to share content. For businesses, the platform offers a valuable space for brand promotion and customer engagement. In the competitive landscape, Instagram's user-friendly interface and constant updates keep it relevant and appealing, making it a key player for personal and professional networking.


 Mobile App Development

Facebook is one of the biggest platforms from which the origin of actual social media begins. Meta designed the app on a cost platform framework, React Native. Facebook was founded in February 2004 at the Cambridge University of Massachusetts. The founder of Facebook is Mark Zuckerberg, and the application generates billions of revenue per year. However, the development cost of Facebook was slightly cheaper and even its further update. Didn't cost a lot to the owner. Overall, Facebook has become one of the leading platforms for social media influencing and connecting with people worldwide.


 Mobile App Development

Telegram is an online portal where people can chat, communicate and create private groups where they can share videos, photos and other links. Users can easily share photo videos, text messages and multimedia files using the telegram. Although it is not a social platform, it is a sort of private chat box where people can communicate without sharing their views on the social platform. Telegram has become a platform for lots of people who want to share their photos and videos privately and have easy conversations. 


 Mobile App Development

Snapchat is a popular chatting platform where people can share photos and videos and make video calls. Snapchat was invented to retain the privacy and confidential information of a user. Earlier, it was very easy and swift to take any screenshot or save pictures without the permission of the admin. However, the privacy of Snapchat records all the data, whether the user is taking a screenshot or recording the video from the chat. Overall, Snapchat is the best platform for people who want to communicate and retain their privacy. Most teenagers prefer Snapchat for sharing photos and videos and communicating online with advanced filters. 


 Mobile App Development

Tinder is the leading dating app used worldwide. The application was created on 12 September 2012. In order to help the teenagers and youngsters to find the perfect match. Users will find multiple options to swipe left and right on the profile And connect with the best suitable match. Moreover, with a paid subscription, a premium member will get a free opportunity to chat with the user after finding a match. In 13 years of development, Tinder is the leading dating app and has millions of users worldwide. 

Also Read : The Future of Social Media App Development Cost Predictions and Strategies


 Mobile App Development

YouTube is an online streaming platform where people can stream live videos or upload videos. It is one of the biggest platforms created by Google. As of now, YouTube has created more than $795.2 crore in revenue. Additionally, it has multiple popular social media influencers who have a net worth of more than billions. Some of the famous YouTube celebrities are PewDiePie, MrBeast, and Carry Minati. Therefore, YouTube is one of the popular video streaming platforms that is available on almost every device and streamed worldwide.

Cash App:

Mobile App Development

Cash App is a famous money-transferring app. You can easily create a profile and link your bank account in the cash app in order to transfer funds from one account to another. The cash app is available in both Play stores and the App Store and is widely used in the United States of America. Cash App supports multiple transferring portals, so it has become easier to send or receive money from any portal directly in your bank account or the Cash App wallet. Additionally, users can directly transfer money in cryptocurrencies using the cash app.

NBA 2K Mobile:

 Mobile App Development

NBA 2K Mobile is a worldwide mobile game that has more than a hundred million downloads and more than 4.5 ratings on both the Play Store and App Store. EA Sports, a leading brand in the creation of mobile games, features NBA. Users can easily download the game and enjoy realistic gaming on their mobile devices. However, the game size is more than 2.3 GB. 


 Mobile App Development

Uber is the best car or taxi rental application. It allows users to book a cab or vehicle to travel from one place to another within the city or outside the city. It provides the best convenience and cheap fares, which make customer travel reliable and safe. Uber is available on both Android and iOS platforms and is leading its competitive market. 

Advantages of AI Integration in Mobile App Development

  • AI enables the creation of personalized user experiences by analyzing user behaviour and preferences. Apps can offer tailored content, product recommendations, and services, leading to increased user engagement and satisfaction.
  • AI algorithms can analyze user data to predict user actions and preferences. It allows apps to proactively offer suggestions, streamline processes, and provide a more anticipatory and user-friendly experience.
  • AI contributes to improved security measures by implementing advanced authentication methods, fraud detection, and anomaly recognition. It ensures a more secure environment for users, protecting their data and transactions.
  • AI can enhance search functionalities within the app by understanding user queries, providing relevant results, and refining recommendations over time. It streamlines navigation and helps users find what they're looking for quickly.
  • NLP capabilities allow apps to understand and respond to natural language input. It facilitates voice commands, speech-to-text features, and language-based interactions, making the app more user-friendly and accessible.
  • AI algorithms can optimize resource usage, such as network bandwidth and device storage, leading to more efficient app performance. It is particularly beneficial for apps that rely on large datasets or multimedia content.
  • AI integration can automate routine and repetitive tasks, reducing manual efforts for users. Its automation not only saves time but also enhances overall user productivity and convenience.

Broad Process of Selecting Mobile App Development Companies 

  • Market Research

Before developing any mobile application, investors must do proper market research about the business so that they can understand customers' demands. Additionally, market addresses also help the investor to navigate what's running in the market so that they can implement such style and fashion in their mobile application to grab the customer's attention. Therefore, understanding the market is an essential part of development, where the user will get all the details about demand and productivity with the complete market. It is very easy to fulfil the requirements of customers and follow the top trends that can enhance the value of mobile applications.

  • Understanding Customer Demand

Customer requirements are another part of development where clients figure out what the demand is in the market. Although it is a part of market research, there is a different segment where clients intensely focus on the requirements of the different apps, reading their reviews and feedback. With the help of Customer requirements, it is very easy to optimize the app as per their needs and fulfil their needs. Moreover, when an application fulfils all the demands of a customer, then there is a high chance of becoming popular and leading in the competitive marketplace. To do proper market research and understand the customer demand to optimize apps as per the need and serve the best application in the competitive business.

  • Pre-App Development Planning

A small but crucial part of development involves pre-development planning and processing. This client can plan for a development that involves the UI UX and the features of the app. When clients make a brief note about the features and design of the app, then it becomes easier for the developers to work on it efficiently. However, if you miss this part of development, then it will take more time and investment, and the developer team and the client have to work together. Although it is not a final design, investors can ask the developer's team to provide feedback and optimize the app as per the market trend. Therefore, planning Mobile app development is important to save time in investment. 

  • App Development Process 

The Main part of a Mobile application is the development process where clients have to invest all their time, money and patience. Clients must hire a perfect team of developers rather than looking for freelancers. Top-notch  mobile app development companies will provide the best result within a client's budget. At the same time, freelancers can take lots of time and can effectively disrupt the client's investment. A complete team will provide better output due to internal coordination, whereas freelancers can impact the overall development of the app.

Clients should be open and transparent with their ideas with the developer team so that they can integrate the features and services as per their needs. So that when the final application is optimized, it contains all the features that the clients and the customers require. 

  • App Quality and Performance Check

After the complete development process, it is time to make a quality analysis of the app. This process involves the elimination of errors and bugs from the app. It might be possible that while developing an app, developers may have left some bugs or errors or might have forgotten some parts of the app. So, to fix this, the developer and the client must work together to check the performance of the app and explore every part of the app. Clients can ask the developers team to run the performance section, find the errors and bugs in the app, and eliminate them as soon as possible. When a mobile application does not have any bugs or errors, then it is very useful and creates a positive impact on the customer's experience. 

  • Marketing 

The last but the most essential part of Mobile app development is planning the marketing strategies. All the marketing is not part of development, but it is essential to divert the customer's attention to the app. There are multiple marketing strategies that clients can implement on the app, including local marketing, social media promotion, paid promotion, collaboration with influencers or popular celebrities and SEO optimization. However, it entirely depends on the client how much they can invest in marketing to improve the app's visibility. However, it is important that any application needs an initial boost to gain popularity so that when it gets into the competitive landscape, it can shine and compete against its competitors. 

Mobile App Development

What Factors Influence the Costing to Make a Mobile App?

  • The complexity of the app, including its features, functionality, and overall complexity of the design, significantly affects development costs. More complex apps with intricate features or advanced functionalities will require more time and resources.
  • Developing for multiple platforms, such as iOS and Android, or choosing cross-platform frameworks can impact costs. Native app development for each platform may be more expensive than using cross-platform solutions, but it can offer better performance.
  • The complexity of the app's design, including user interface (UI) and user experience (UX) considerations, influences costs. A more sophisticated and customized design will typically require more effort and resources.
  • If the app requires a robust back-end infrastructure, such as servers, databases, and APIs, the development cost will increase. Complex back-end systems for handling data, user authentication, and server-side logic contribute to higher expenses.
  • Integrating third-party services, like payment gateways, social media APIs, or analytics tools, can impact costs. The complexity of integration and the number of external services used contribute to overall development expenses.
  • Apps with stringent security and compliance requirements, such as those handling sensitive user data or financial transactions, may require additional resources and specialized expertise, affecting development costs.
  • Rigorous testing processes, including manual and automated testing, are essential for ensuring the app's reliability and performance. The more extensive the testing, the higher the associated costs.
  • The location of the development team influences costs. Development teams in regions with higher living and labour costs may charge more for their services compared to teams in regions with lower costs.
  • Factoring in ongoing maintenance, updates, and customer support after the app's launch is crucial. Post-launch services contribute to the overall cost of app ownership.
  • Efficient project management and clear communication are vital for successful app development. The complexity of managing the development process and communication channels can impact costs.

Which framework is effective for Building the best mobile application for multiple platforms? 

Mobile App Development

In the wide diversity of mobile app development services, it is very hard to decide on the perfect framework for your development process. However, multiple frameworks work efficiently and imperfectly in creating a mobile application. However, there are two major frameworks, Flutter and React Native, that developers widely use to create cross-platform applications for the user. 

Out of both, Flutter is one of the most updated and best output delivery platform applications that can create mobile applications for Android, iOS and the web with a single code. Additionally, Google developed Flutter, and it is very effective in producing mobile applications using it. Moreover, developers also prefer Flutter Overactive due to its efficiency and the output delivered while creating a mobile application, so investors can also check out the best Flutter app development company that can build you a perfect application as per your needs. 


Mobile application development is the essential process of raising the business on the global level through an online portal. Explore the diversity of mobile application development and the categories that can empower your business. Also, if you want to begin a startup, then understand the requirement of a mobile application to profit your business by capturing the customer accumulation with a perfect app.

Moreover, I also understand the cost of Mobile app development and the best framework to create a perfect app. However, it won't be possible without a perfect Mobile app development company that can fulfil all your desires and demands. So look out for the best app development company that can deliver your ideas and innovation into reality. 

Additionally, if you own any business, then look for the Perfect mobile app that can suit your brand name and bring more traffic to your business. It will give a boost to your business from the saturation level and improve your company's quality and services. Moreover, every business needs a captive market that showcases service on the global platform. It is only possible through a perfect mobile application that delivers better results, drives traffic and brings excellent revenue to the company. 


Q1 Why does a mobile application need marketing?

Mobile applications need marketing to improve the visibility of the app even after its launch on the digital platform, Google Store or App Store. With the help of marketing, investors can spread awareness about the presence of their app that serves best in their category. However, if you do not focus on marketing strategies, then it will be hard to bring the customer's attention and the growth of the business.

Q2 Which is Better: Flutter vs React Native?

Both platforms work efficiently on their part, but developers recommend Flutter over React Native because Developers get more options to optimize the app as per their needs and deliver better results. Meanwhile, recitative work on outsourcing plug-ins involves lots of time and idea planning, which might become hectic for the developers. 

Q3 How much does a Dating App Cost?

To create a dating app like Tinder or Bumble, clients have to pay approximately $30,000 to $50,000 as per the requirements and the features of the app. If your app contains the complex structure and features of Tinder, then it will range up to $50,000. 

Q4 How does a mobile application impact the Startups?

Mobile applications heavily impact startups as there are slight chances of the Startup gaining popularity at the initial stage. But with the mobile application, the Startup becomes verified, and people will believe in the legitimacy of the domain. Moreover, with proper marketing strategies and social media pages, a startup can boost the audience accumulation in their domain.

Q5 Can developers create exact replicas of YouTube?

Yes, a professional developer team is capable of creating a replica of YouTube, but it might cost a lot of investment and time. However, the market size of video streaming apps is huge, so it is very hard to compete with the leading brands. But with the help of a top video streaming app development company, clients can create a perfect app like YouTube.