Building Micro Apps for App Marketplaces
Mohit R- 10 Feb 2025
Building platform integrations and apps for marketplaces is a smart strategy for indie hackers and small product developers. Using Rob Walling's Stair Step Methodology, you can start small, learn the ropes of launching software products, and gradually build more sophisticated and scalable businesses. The idea is to begin with small, simple projects (often one-time-purchase apps) and use them as stepping stones to bigger SaaS ventures.
Credits: Photo by Eduardo Soares on Unsplash
Market data reveals that there are significant gaps and untapped opportunities in various marketplaces, such as the Chrome Web Store and Shopify App Store. These gaps provide a chance for developers to solve niche problems, reach large audiences, and generate recurring revenue. These marketplaces act as ecosystems where millions of users actively search for solutions to extend the functionality of their favorite tools.
Marketplaces refer to these apps in different ways: plugins, extensions, integrations, or micro apps. Despite the terminology differences, they all offer similar benefits: easy discovery, built-in distribution channels, and access to existing user bases. For indie hackers, marketplace apps offer a lower-risk entry point compared to building full-fledged SaaS products from scratch.
Top 10 Marketplaces to Build Micro Apps
1. Google Chrome Web Store
About the Marketplace: The Chrome Web Store is the go-to platform for publishing browser extensions that enhance the browsing experience.
Size of the Marketplace: Over 137,000 extensions and millions of daily users.
Popular Niches: Productivity encompasses 62,127 extensions, accounting for 55.5% of the total, Lifestyle comprises 37,319 extensions making up 33.3% and Customization theme includes 12,487 extensions, representing 11.2%. (chrome-stats.com)
Case Study: YT Notes chrome extension helps students and professionals generate structured notes from YouTube videos while watching them. By integrating directly into the browser, YT Notes makes the note-taking process seamless and efficient, turning video content into organized, actionable insights.
App Idea: A tab manager extension for freelancers and remote workers to organize and save workspaces.
2. Google Workspace Marketplace
About the Marketplace: This marketplace allows developers to build apps that integrate with Google Workspace tools like Gmail, Google Docs, and Google Sheets.
Size of the Marketplace: 5,000+ apps with millions of installs. Google Workspace boasts over 3 billion users globally, with more than 8 million paying customers. (explodingtopics.com)
Popular Niches: Email productivity, data analytics, workflow automation.
Case Study: Mailsuite for Mobile integrates directly into the Gmail app on iOS and Android, letting users track email opens in real time with no third-party apps. The double-checkmarks show who read your emails, Mailsuite have more then 3M+ downloads and used by for sales, support, and project management on the go.
App Idea: A Google Sheets add-on for small businesses to track recurring tasks and deadlines.
3. RapidAPI Marketplace
About the Marketplace: A hub for discovering and connecting to APIs.
Size of the Marketplace: Currently supports over 40,000 APIs, over 12,000 API publishers, over 200,000 monthly active subscribers, millions of registered developers, and over 5 billion API requests a month.
Popular Niches: Weather data, machine learning APIs, financial data.
Case Study: Skill Parser API, a skill extraction and parsing API, helps developers analyze job descriptions and resumes to identify relevant skills using natural language processing and machine learning. It is widely used for job matching, resume parsing, skill gap analysis, and HR data enrichment.
App Idea: An API that aggregates freelance job listings from various platforms.
4. Shopify App Store
About the Marketplace: Shopify's marketplace is dedicated to apps that extend e-commerce functionalities for Shopify stores.
Size of the Marketplace: As of January 22, 2025, the Shopify App Store hosts 12,315 apps, with 266 added in the preceding 30 days. Approximately 87% of Shopify merchants utilize the App Store. (appnavigator.io, shopdetector.com)
Popular Niches: Inventory management, marketing automation, customer reviews and SEO.
Case Study: Klaviyo, is a marketing automation platform that enables businesses to create personalized customer experiences across email, SMS, and mobile push notifications. Leveraging real-time data and AI insights, it offers features such as segmentation, automated workflows, and analytics to enhance customer engagement.
App Idea: An app for personalized discount recommendations based on customer behavior.
5. Slack App Directory
About the Marketplace: Slack's app directory hosts integrations that improve communication and collaboration.
Size of the Marketplace: Slack App Directory hosts over 2,600 apps. It's noteworthy that over 7,50,000 organizations globally utilize Slack. Additionally, more than 6,50,000 custom apps are employed by these organizations. (Axolo Slack Stats)
Popular Niches: Project management, notifications, HR tools.
Case Study: Donut is a Slack app designed to foster team camaraderie by automating introductions and facilitating social interactions among colleagues. It has facilitated over 15 million connections and onboarded more than a quarter million new hires for 20,000+ enterprises.
App Idea: An onboarding checklist app for new hires in remote teams.
6. Monday.com Apps Marketplace
About the Marketplace: Monday.com is a work management platform that allows developers to build apps that enhance workflows.
Size of the Marketplace: More than 250 apps available as of 2024. Since its launch, the marketplace has seen over 1.5 million visitors and 380,000 app installations. (PR Newswire)
Popular Niches: Workflow automation, reporting, CRM tools.
Case Study: General Caster, enables users to perform advanced calculations and operations without relying on the platform's formula column. It supports functionalities such as currency conversion and Excel-like formulas, enhancing workflow automation within monday.com.
App Idea: A time tracker that integrates with Monday.com boards.
7. WordPress Plugin Repository
About the Marketplace: The largest open-source platform for building websites, WordPress offers a plugin repository to extend site functionality.
Size of the Marketplace: Over 59,000 plugins. WordPress powers approximately 43% of all websites globally with around 501.28 million websites built on WordPress. Given this substantial market share, it's estimated that hundreds of millions of users actively use various plugins to enhance their websites functionality. (wpzoom.com)
Popular Niches: SEO, e-commerce, security, performance optimization.
Case Study: Yoast SEO plugin designed to enhance website visibility by optimizing content for search engines. It offers features like AI-powered suggestions, internal linking tools, and real-time SEO analysis to help users improve their site's ranking.
App Idea: A plugin for generating AI-powered content briefs.
8. Google Play Store
About the Marketplace: Google's app store for Android apps.
Size of the Marketplace: As of February 2025, the Google Play Store hosts approximately 1.57 million applications with an average of 1,212 new apps released daily. (appbrain.com, 42matters.com)
Popular Niches: Games, productivity, health and fitness.
Case Study: Evernote, a note-taking app, scaled massively through its Android app.
App Idea: A habit tracker with gamified rewards.
9. HubSpot App Marketplace
About the Marketplace: HubSpot's CRM-focused marketplace allows for building marketing, sales, and service integrations.
Size of the Marketplace: As of June 2024, the HubSpot App Marketplace offers over 1,500 integrations and apps. (nexalab.io)
Popular Niches: Lead generation, email marketing, sales automation.
Case Study: Aircall, a cloud-based phone system, integrates seamlessly with HubSpot.
App Idea: A tool that syncs webinar attendees as leads in HubSpot CRM.
10. Microsoft Office 365 Marketplace
About the Marketplace: A marketplace for apps that integrate with Microsoft Office tools like Word, Excel, and Outlook.
Size of the Marketplace: A vast platform with a large number of third-party applications and add-ins available for various Office applications like Word, Excel, PowerPoint, Outlook, and Teams, making it a very large marketplace with thousands of options depending on the specific needs of users and businesses. The exact marketplace size is not publicly stated by Microsoft.
Popular Niches: Document automation, productivity tools, collaboration.
Case Study: Paperpal is an AI-powered writing assistant built for academics. It integrates directly into Microsoft Word, offering real-time language checks, grammar corrections, and citation suggestions. Paperpal helps reduce the time spent on academic writing while improving the quality of academic work.
App Idea: An Excel add-on for generating financial projections automatically.
Other Notable Marketplaces
Beyond these top 10, there are several other marketplaces worth exploring:
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Atlassian Marketplace: Ideal for building Jira and Confluence integrations.
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Stripe App Marketplace: Focused on payment-related integrations.
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Canva App Marketplace: Great for building design tool add-ons.
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WooCommerce Marketplace: Excellent for e-commerce plugins.
For a more detailed list, check out Rocketgems' SaaS Marketplaces.
Should You Build Platform Integrations?
If you're an indie hacker or small product developer, building platform integrations allow you to leverage the established ecosystems of marketplaces like the Chrome Web Store, Shopify, or Slack to reach large audiences with minimal marketing efforts. Unlike full-fledged SaaS products, micro apps or integrations can be quicker to develop, require lower upfront investment, and offer a ready-made user base.
But is it the right move for you? Consider your skills, available resources, and long-term goals. If you're aiming for a faster go-to-market strategy or want to validate a product idea with less risk, platform integrations are a great starting point. However, they do come with trade-offs, such as revenue sharing and dependency on the marketplace's policies.
Let's explore the pros and cons in detail.
Advantages of Building Platform Integrations
1. Access to a Ready User Base
One of the biggest advantages of building marketplace apps is instant access to a large user base. You don't need to build your audience from scratch. Marketplaces actively promote new and top-performing apps, giving you significant visibility right from the start. This reduces your customer acquisition costs compared to building a standalone SaaS product, where marketing can consume a huge part of your budget.
2. Built-in Distribution Channels
Marketplaces take care of the heavy lifting in terms of distribution and discovery. They provide search functionality, app categories, and user reviews all of which help your product get discovered. You can focus more on building a great app and less on worrying about setting up distribution pipelines or marketing funnels.
3. Lower Initial Investment
Building an integration or micro app is often less resource-intensive than developing a full SaaS platform. You don't need to create your own infrastructure, payment system, or user authentication most of that is handled by the platform. This allows you to start small, validate your idea, and iterate quickly. A Google Workspace add-on or Slack bot can be built within weeks and launched to thousands of users at a fraction of the cost of a standalone app.
Disadvantages of Building Platform Integrations
1. Dependency on the Platform
While leveraging a platform's ecosystem has its advantages, it also makes you dependent on its policies and decisions. Platforms can change their guidelines, limit functionality, or even shut down access to certain features, directly affecting your app and business. This risk means you're not in full control of your product's future.
For exampleApple's App Store policies are known for frequent changes, which sometimes result in apps being removed or restricted, affecting developers' revenue streams.
2. Revenue Sharing
Most marketplaces take a cut of your earnings, typically ranging from 15% to 30%. While this fee might be worth it for the exposure and support, it can significantly eat into your profits, especially for low-cost apps. You'll need to price your product strategically to maintain profitability while staying competitive.
3. High Competition
Popular marketplaces attract thousands of developers, making it harder to stand out. Some niches are already saturated with established players. To succeed, you'll need a clear unique selling proposition (USP), excellent user experience, and continuous updates to stay relevant.
Focus on solving a very specific problem for a niche audience rather than trying to build a generic solution. Niche apps often perform better in competitive marketplaces.
How to Monetize Marketplace Micro Apps
1. One-Time Purchase
Charge a flat fee upfront for lifetime access to your app. This model works well for simple tools that provide immediate value without needing ongoing updates or support. It's a great way to generate quick revenue, but it may limit long-term earning potential. For example a Chrome extension for converting web pages to PDF could be offered for a one-time fee.
2. Subscription
Offer your app for recurring monthly or annual payments. This model provides a steady revenue stream and encourages you to continually improve and update your product. Subscriptions are ideal for apps with ongoing value, such as automation tools or analytics solutions. For Example a Google Sheets add-on that offers real-time financial dashboards and updates could be priced as a monthly subscription.
3. Freemium
Provide a free version with basic features and charge for premium upgrades. This model helps you build a user base quickly and convert free users into paying customers by offering additional functionality, integrations, or advanced features. For example an email productivity app with limited automation for free users and advanced automation for premium subscribers.
4. Commission-Based
Take a percentage of each transaction facilitated through your app. This model aligns your revenue with the success of your users. It's often used for apps that enable e-commerce, bookings, or marketplace transactions. For example a Shopify app that connects merchants with influencers and takes a small percentage of each successful sale.
Building micro apps for marketplaces offers an exciting opportunity for indie hackers and developers to create valuable products with minimal risk. By leveraging existing platforms, you can focus on solving niche problems, grow your user base faster, and build a sustainable business. Whether you're just starting out or already an experienced developer, now is the perfect time to dive into app marketplace and make an impact!
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