With new problems popping up every day, you need robust solutions to keep them all under control. Even if you have an IT team to build internal tools for you, their backlog is probably full of higher-priority tasks.

For businesses that can't wait to move forward, internal tool builders can help you develop custom apps for every problem—in as little as a few hours, once you're familiar with the platforms. No more juggling all varieties of data sources: all the data is centralized, ready to be plugged into a user interface with custom logic buttons included.

I've spent a lot of time tinkering with and writing about app builders, and this time, I researched and tested the top internal tool builders to find ones to help you solve problems, stay agile, and enhance your productivity. Based on all my testing, here are the best internal tool building platforms.

The 10 best internal tool builders

• Glide for a no-code solution

• Stacker for a no-code solution with lots of data sources

• Zapier for automation

• Google AppSheet for starting from a spreadsheet

• Quickbase for building mini-apps with AI

• Microsoft Power Apps for advanced logic without code

• Budibase for an open source solution

• Retool for extending with code

• Appsmith for usage-based pricing

• OutSystems for an enterprise-grade solution

What is an internal tool builder?

An internal tool builder is a platform that lets you build custom apps for you and your teammates to use at work. That might be a bespoke CRM, a customized task management app, a social media tracker, an editorial calendar, or anything in between.

It's important to remember that internal tool builders are different from other app builder platforms. They focus on data and functionality, providing the flexibility to let you solve internal business problems. You'll be able to set up dashboards to view all your data with one glance and add interfaces and buttons to make quick changes. For your teams, you'll be able to create a set of customizable apps to streamline day-to-day work.

If you're a spreadsheet user who's looking to level up, you might want to start with this list of the best database-powered app builders. Or, if you're looking to build any kind of app (not just for internal use), you can check out this list of the best no-code app builders. And if you're still not sure, I wrote a guide to picking the right app builder.

What makes the best internal tool builder?

The most basic tools here will offer various data connections, a way to display that data using a collection of UI components, and all the create, read, update, and delete (CRUD) actions to manage data. More advanced solutions will let you customize the user experience, add advanced logic, and even set up workflow automation.

Here's what I looked for when testing all the internal tool builders:

• Development options. While I prefer no-code, I looked for platforms that offer a combination of development methods, including low-code and full-code. This should make it flexible to let your non-technical team members create apps and your IT department scale them.

• Data sources and integrations. I looked at the range of data sources you can connect to your internal tool builder, along with third-party integrations to help you move data around and trigger automations.

• Flexibility and customization. The apps in this list will help you create common internal tools, such as a CRM or an inventory manager, along with more specialized solutions, offering a good range of customization settings.

• Scalability, performance, and reliability. I looked at uptime reports where available, read user reviews on this particular topic, and ran performance tests in the editor and the apps to make sure they don't break easily.

• Platform reputation. I'm prioritizing platforms that have a proven track record and that look like they're sticking around for the long run.

I tested these apps over the course of one month. After signing up for each one, I created apps from scratch and from templates, following the available help guides. I built a few CRMs, a seasonal promotion tracker, a project management tool, and an internal onboarding guide, among a few others. Whenever I faced low-code or code challenges, I used ChatGPT to understand the requirements and put together a few code lines to make things work.

What are no-code, low-code, and full-code?

I labeled each app to give you an idea of how much code is required to use each one. You can take a look at Zapier's guide to low-code vs. no-code for more details, but here's the gist:

• No-code means the platform has a series of visual processes to let you create your app. These include point-and-click controls, drag-and-drop elements, and language that makes it easy for non-technical users to start building apps.

• Low-code tools come in two flavors (note: this is my distinction). Easy low-code only requires you to know a bit of SQL for working with data and JavaScript or Python for building advanced logic; everything else is no-code. Hard low-code are developer tools: shortcuts for time-consuming processes in the app development process, requiring a deep understanding of code and digital infrastructure.

• Full-code. I added "full" to differentiate it from the other options. In this article, it means you'll need computer science or engineering training, or equivalent professional experience.

The best internal tool builders at a glance

Best internal tool builder for a no-code solution

Glide (no-code)

Glide pros:

• Very intuitive

• Lots of templates

Glide cons:

• Limited data connections available on non-enterprise plans

I'm always impressed when I hit the preview button on a Glide app. The user interface is sleek, with discreet animations to add a bit of fun to the work. The fact that it looks so good tricked me into thinking that it's not powerful under the hood—and then I found the advanced logic pop-up. The experience is entirely no-code, giving you plenty of building freedom without requiring dozens of hours of training.

All the apps you build here are responsive, looking great on all screens, especially mobile. For desktop, you may have to experiment with the page width settings to make text easier to read. It leverages smartphone features such as the camera, so you can take pictures inside your app and add them to a field inspection file or an inventory tracking database.

The AI wave hit Glide, too, letting you integrate shiny features into your apps: text generation, text-to-image, data extraction, and audio-to-text. You can add these screens to your app, making it easier to send your data into an AI model without tabbing out to ChatGPT. Take a look at how they work in this template.

Looking at the pricing page, Glide seems to target individuals and smaller businesses, judging from the number of seats in each plan. In the lower plans, you can use the native database, Google Sheets, Airtable, and Excel to store your data. If you want to connect your developer-grade databases, you'll have to talk to sales to hop on the Enterprise plan. 

And speaking of connections, you can link Glide and Zapier together to integrate and automate other apps you use. Here are a couple of examples.

One last heads-up for pricing: each plan has limitations on number of stored records, total storage, and number of CRUD operations. If you're going to use these apps heavily, be ready to upgrade sooner.

Glide feels great to use, both while building apps and while using them to tackle your work. It's also the perfect place to start if you've never built an app before: the available help content is one of the best out there.

Glide price: Free plan available. Starter plan, at $25/month, lets you publish up to 5 apps for 110 total active users.

Best internal app builder for a no-code solution with lots of data sources

Stacker (no-code)

Stacker pros:

• Start quickly from a spreadsheet

• Plenty of data views and filtering tools

Stacker cons:

• Limited advanced logic

With Stacker, you can bring in data from Google Sheets or Airtable, as well as a very large range of developer-grade databases, CRMs, and other third-party apps. It's a really good option if you have lots of data spread out across multiple platforms, offering an easier way to connect them without migration or importing/exporting.

Your apps' icons will sit on the right side of the screen. When you click into one of them, you'll be able to see all the tabs inside that app. You can quickly switch between your CRM and your customer support portal and any other tools you're using. Stacker supports all the CRUD actions itself, but if you need to add advanced logic, you can connect Stacker to Zapier. Here are a few examples of how that works.

When creating a new app with an empty database, you can start building it on the spreadsheet. Add as many columns as you need, choosing the appropriate data types and names for each one. Once you have everything, you can hide the spreadsheet and start adjusting the visuals. In the app layout tab, you can choose which view to apply—from a simple list to a Kanban board, with a few more options in between—as well as control the visibility of columns, so you don't overwhelm yourself with data you don't need to see.

If you're a spreadsheet fan, Stacker will feel like a natural transition to building internal tools. It's trusted by giants like Adobe and Samsung, so you'll be in good company. No more scattered data sources: everything will find its place inside Stacker.

Stacker price: Starter plan is $79/month for 1 app and unlimited external users.

Best internal tool builder for automation

Zapier (no-code)

Zapier pros:

• Integrates your app with over 6,000 apps (and counting)

• Allows you to set up complex step-by-step logic

Zapier cons:

• Still in development

Zapier is a no-code automation platform. Each automation is called a Zap: you set a trigger, and then create a series of actions that will happen next. And since it connects with over 6,000 apps, you can create your own advanced logic to bring together all the apps you use at work.

What I just described is equivalent to the logic features in other internal tool builders on this list. The only thing that Zapier needed to become a fully-fledged app builder was the ability to build a user interface and a place to store data. And that's exactly what Zapier built: Interfaces and Tables are two new products that turn Zapier into a powerful internal tool builder.

You can add user interface components to display and capture data from the user, which can be stored in Zapier Tables, or sent to whatever other app you want. You can spread the experience across a sequence of pages, making it easy to streamline internal processes. And what makes it unique is that you can add a new Zap to any button in Interfaces, acting as a starting point for complex automation runs. There are components that let you interact with AI, too, so you can add intelligence to conventional automation.

Interfaces is still in development as I write this, so I imagine there's a lot to come in the future. It's evolving at a really great pace, and your feedback can influence the development process. If this is interesting to you, hop in. You can start from scratch, or get started with one of these templates:

• Simple CRM

• Approval request table

• Social media planner template

Zapier price: Free plan available. Starter plan at $19.99/month (billed annually) for 750 tasks per month and multi-step Zaps. Interfaces and Tables are priced separately, but both have generous free plans to start with.

Best internal app builder for starting from a spreadsheet

Google AppSheet (mostly no-code; easy low-code for advanced features)

AppSheet pros:

• Generates an app based on your spreadsheet

• Interesting extra features, such as machine learning on your data

AppSheet cons:

• Editor interface is a bit unintuitive

All the solutions on this list let you configure your data sources, edit your user interface, and keep hitting the preview button as you test and implement more features.

Google AppSheet has a different philosophy. Upload one of your spreadsheets, and AppSheet will use its AI engine to sketch an app you can use to interact with the data and data types on it. After that, you can customize each page of the app with a set of menus that have the cleanliness that Google has made us expect. The whole user experience is very Google, both while building the app and in terms of how your final app feels. The terminology is a bit advanced in some of the interactions, but there's a lot of help (including a free video course on Udemy) to support you through the process.

I uploaded a spreadsheet with data for fictional employees, and AppSheet built a simple profile view and button to let me edit each entry. In five minutes, I was able to create a form to add new employees with a quick Google search and a couple of clicks.

The best part: AppSheet builds apps that are responsive, looking great on any device. You can even include features that smartphones can take advantage of, like barcode scanning (albeit those features come at a higher price point). Other interesting features include machine learning and text recognition to add some artificial intelligence to your builds.

You can build and edit all you want, for as long as you want. AppSheet will only start charging when you're ready to deploy your app to a live setting. While the setup time for Google AppSheet is longer and the learning curve a bit steeper, the range of solutions you can create is potentially much wider.

You can do even more with AppSheet by connecting it to Zapier to do things like creating a new record based on a sale or form submission. Here are some examples to get you started.

Google AppSheet pricing: Free to build; deploying an app starts at $5/user/month with basic application and automation features.

Best internal app builder for building mini-apps with AI

Quickbase (no-code)

Quickbase pros:

• Enterprise-grade no-code

• High data security

Quickbase cons:

• Interface feels a bit dated

Quickbase has a discreet but effective AI-powered app-building feature. When you start building a new app, you can select to generate one with AI. There are a few input fields where you fill in your objectives, and once you click create, you can lean back and wait a bit—quite a bit, as the engine takes some time to bake it.

When it's ready, you'll have a basic version of what you asked for, complete with a set of notes used to generate the app. I asked for a CRM, and I got an app with most of the UI and data sources ready. All I had to configure were the actions and some connections between data and logic.

You can keep leveling up your workspace with more apps, each one tackling a specific problem or assisting a department. You can import your spreadsheet data into Quickbase or integrate with most of Google Workspace and developer-grade databases.

When you choose to start from scratch, Quickbase imposes a helpful sequence: you start by creating the data types you'll be working with and connect them together in relations if needed. Once you click Create App, you get the list views of all of these databases.

All apps you create here will have the same user experience: you can configure a homepage that acts as a dashboard for metrics and common action buttons. Then, you have a series of database views in other tabs where you'll actually do work, along with forms to feed and edit entries in that database.

Quickbase's experience is more on rails than others, feeling like empowered spreadsheet software. It may not look as polished as some of the competition, but it's robust, letting you see and work on your data without having to tinker with code. You can configure workflow automation within the app too, but only for apps that integrate natively with Quickbase. For everything else, you can use Zapier. Here are some examples to get you started.

Quickbase price: Team plan at $35/user/per month for a minimum of 20 users

Best internal tool builder for advanced logic without code

Microsoft Power Apps (easy low-code)

Power Apps pros:

• Runs on Microsoft Azure and integrates with all Microsoft products

• Extremely flexible

Power Apps cons:

• Some useful advanced features are priced separately

Microsoft Power Apps feels like the super-powered grandchild of the classic Microsoft Access. It's a Microsoft product through and through, with the user experience we've grown used to. I'm blown away by how much you can do with Power Fx, a formula language for Power Apps that lets you build advanced logic without having to code. The syntax is similar to spreadsheet formulas, making it easier to learn, read, and understand.

It has the highest number of native integrations with third-party apps when compared with others on this list. It works with all the business-oriented Microsoft 365 apps like SharePoint, Microsoft Azure web services, and a huge range of other apps—from familiar faces such as Dropbox to specialized enterprise-grade software.

What I love about Power Apps is its flexibility. You can start building by importing data, by putting together the user interface, or from a template. You can see all your data in a single tab in the dashboard, configure multi-step flows, or even start training an AI model. The more I clicked through the tabs, more possibilities popped up. The flexibility is there in the editor, too, letting you add plenty of UI components and customize their look and functionality.

Usually, the more power you have in your hands, the more difficult the platform is to learn. This isn't necessarily true for Power Apps. There's a quick tour on the homepage that gives you a pretty complete idea of everything you can do. When using the app itself, the controls feel intuitive—as if PowerPoint was overhauled with magic buttons. And with the Power Fx that I mentioned before, you can advance a lot faster once you get familiar with the basics.

This is the first time I've ever used Power Apps, and it's the app on this list that surprised me the most. Even if you end up not using it, I encourage you to take the guided tour, sign up for a free account, and try it out yourself.

Microsoft Power Apps price: Premium at $20/user/month. Features such as web page publishing and training AI models are priced separately.

Best open source internal tool builder

Budibase (easy low-code)

Budibase pros:

• Offers automation features

• Used by well-known companies

Budibase cons:

• Advanced security and auditing are paid features even if you self-host

Budibase is open source, and it gives you most of its features for free if you want to self-host it. If you don't know how to do it, be sure to have an IT person do it for you—deploying Budibase in your servers isn't a walk in the park.

The platform itself feels great to use. The app editor window is clean, with all the controls grouped up and organized in four major tabs:

• Data lets you create a new data source or connect an existing one. You can bring in everything you need to power this specific app and manage it in this tab.

• Design lets you add the screens of your app, fill them with UI components, display data, and configure what each button does.

• Automation lets you configure step-by-step actions that happen when a trigger is activated.

• Settings contains a few useful controls for backing up your app, managing versions, and even embedding this app inside other tools.

One quick note on the design: while other internal tools don't care much about the aesthetics, Budibase locks you in a pleasant design system, with balanced spacing between elements and good color rules to differentiate visual elements—especially useful at the end of a busy workweek. You can choose one of eight color schemes, including light and dark modes to respect your eyes day and night.

The fact that you can build apps and set up your own automation makes Budibase quite flexible, especially considering the (non-existent) price point for self-hosting. It's trusted by big companies like Netflix, Tesla, and Google—you'll be in great company if you choose Budibase to build your internal toolkit.

Budibase price: Free when self-hosted for basic features. Self-hosted Business plan starts at $20/user/month for advanced security, automation, and user group features. Free plan available on the hosted plan, with plans starting at $10/user/month.

Best internal tool builder for extending with code

Retool (easy low-code for basic features, full-code for advanced features)

Retool pros:

• Builds workflows, web, and mobile apps

• Database management features available

Retool cons:

• Editor slows down while building complex apps

Retool is a comprehensive tool, covering lots of possibilities on one single platform. Building the UI is mostly a no-code experience, and displaying data and binding a few actions are still doable for non-technical users, too, since the SQL queries involved aren't hard to understand. But Retool gets interesting when you use JavaScript to create more powerful actions.

The way Retool thinks about UI makes sense—the components were optimized for quick interaction and offering deep functionality. If you love dashboards with lots of data and plenty of buttons to control operations in real time, Retool definitely supports those mega-pages. If you prefer multi-tabbed apps with separate angles to look at your business, there's freedom to build that as well.

It's easy to integrate AI into your workflows with Retool. Not just GPT: you can bring any other AI model into the mix, be it Anthropic's Claude 2, Microsoft Azure's Cognitive Services, or the AI model you've been training in Hugging Face. Bring your API key and start cooking. More than text generation, you can add any other task, including image recognition, object detection, translation—really any task that AI models can handle right now.

While it feels like a tool that shines in the hands of backend engineers—the people who handle the invisible processes behind apps and web services—you can still build a few simple apps without having to write code. It definitely depends on how comfortable you are with trial and error and tinkering. Try it out to get a feel of the difficulty if you're interested in Retool's features as a whole.

Retool is a highly flexible low-code tool, trusted by big clients such as Amazon and OpenAI. If you have coders and IT people to set it up, you'll be able to wire up apps for any use case—including edge use cases—in a shorter amount of time.

Retool price: Free plan available. Team plan at $10 per standard user, $5 per end user per month.

Best internal app builder for volume-based pricing

Appsmith (hard low-code)

Appsmith pros:

• Clean, well-organized editor interface

• Plenty of developer-grade data source connections

Appsmith cons:

• Limited freedom for non-technical users

You may be shopping for a tool that's going to simplify a few core processes but that you won't actually use every day. It wouldn't make sense to pay full price for just a couple hours of work every week. That's why Appsmith is here.

The pricing is unique among all the options in this list, offering a $0.40 per hour rate whenever your team is using it. This is capped at $20 per month, so you don't have to worry if you use it more than you planned. This only works on a self-hosted basis, so this is a better fit if you already have your infrastructure. If you don't have one, you can still sign up for the Community plan, a generous free option with most of the features available.

Even though you can build the interface using a no-code approach, Appsmith leans more toward the hard low-code region. The right tab has code terminology that may put off non-technical users, making things seem more complex than they need to be. At the same time, all data queries have to be created in SQL, and all the logic is all about JavaScript—in fact, it has a built-in JS editor that makes the experience of writing code a bit more convenient, offering features like autocomplete and code debugging.

It's definitely a better match for teams who have their own IT expert. Once they set up Appsmith and create the queries and actions with code, you can jump in to create your own apps. When the user interface is ready to go, just bind the correct actions to the appropriate buttons and test. Feeling brave? Try typing /ai into a code block, and write a prompt: Appsmith will generate JavaScript code with AI. It's not accurate 100% of the time, but it did make a few things work during my test session.

Appsmith price: Free hosted plan available. Self-hosted Business plan starts at $0.40/hour/user, capped at $20/user/month.

Best enterprise internal app builder

OutSystems (full-code)

OutSystems pros:

• Very robust

• Customizable integration with existing platforms and data

OutSystems cons:

• Tough learning curve for semi-technical people

OutSystems brands itself as a low-code platform. If you're a developer, that's definitely true. If you're a non-technical user, it's going to be hard to leverage everything this platform has to offer.

OutSystems works at the enterprise-grade level, offering a scalable and reliable infrastructure for companies that are already working with multiple platforms. Each new app that you create gets its own development environment, running its own analytics and logging engines, enabling all the tools that you need to actually create the app. Once you publish it, this platform will convert everything in the editor into high-performance code and create separate instances for all the services required to run it.

This provides some level of isolation between apps, giving you more control over data and logic. You can choose to connect OutSystems apps to one another at the platform level and even with external integrations, so you can work with data inside OutSystems or part of your data pool.

To start creating an app, you'll need to create an account online and download the desktop app, the OutSystems Service Studio. This editor feels almost like a crossover between a low-code app and an integrated development environment (IDE) like Visual Studio. The right tab has a files-and-folders view for everything inside your app, from visual elements to scripts. The debugging features include precise controls to run your app step-by-step, helping you fix unintended behavior.

OutSystems ranks highly in both Gartner and Forrester's studies, slightly outpacing its closest competitor Mendix (which you can check out for comparison). The first app you build is free, but beyond that, you'll be set back $1,513 per month, making this platform a much better fit for bigger businesses with huge pain points in their digital infrastructure.

OutSystems price: First app is free. Paid plans start at $1,513/month.

What is the best internal tool builder?

Internal tool builders are the answer to the question "is there a way we can do this faster and with fewer mistakes?" Yes, there is. Connect your data sources, build an interface, set up the logic, and get more done with less effort, in less time.

There are apps on this list for every type of user: beginners who are just learning what no-code means, tech-savvy people who have a good mental picture of how apps work, and IT professionals who want to add their own code and keep an eye on security and performance. Take the internal tool builder that best matches your needs and skill level for a ride, and see how it can simplify your work.

Related reading:

• Stop paying for software you can build yourself

• How to create a lead capture form with Zapier Interfaces

• Why pairing AI with automation will change how you work

• The best AI app builders