You never get a second chance to make a first impression. Apps and digital tools need to have the best possible design, as it will influence not only how users feel about your product but the brand itself. In fact, brands with good design are thought to be more trustworthy, with nearly half of users finding design a factor in assessing credibility, as reported by Stanford researchers.

This makes user interface (UI) APIs some of the most essential tools in any UI designer or developer’s arsenal. APIs for UI designers can interact with databases, analyze user behaviors, import design assets, and even manage colors and fonts — all from the development environment. We’ve put together ten of the most useful APIs for UI designers, giving you everything you need to upgrade and refine your UI design workflow and improve your end-user experience.

1. The Noun Project API

Every designer needs icons. Bonus points if they’re high-quality, lightweight, and well-organized. The Noun Project API satisfies all of these criteria by a long shot. It features over 8 million icons depicting nearly anything you can think of, all of which can be returned as either a vector or a PNG file.

2. Color API

Color API is a Swiss-Army knife API for color. The Color API identifies colors, generates palettes, returns assets for specific colors, converts between virtually any format, and returns the analysis in nearly any format you could ever want. It also has only two endpoints, making the Color API incredibly easy to work with.

3. Google Fonts API

Google Fonts API is a must-have for any UI developer working with fonts that doesn’t feel like lugging around a cumbersome font suitcase. The Google Fonts API lets UI designers experiment with fonts using API calls, guaranteeing that assets are universally available and their UI looks and performs the way it should. It also allows developers to make basic changes to the fonts and design from their development environment, rather than having to use a browser plugin or extra tab.

4. UI Gradients API

No one wants to be limited to simple, static colors — especially customers and users! The UI Gradient API is a simple, straightforward design API that lets UI developers integrate crisp, gorgeous color gradients into their UI design using a simple API call. It also lets developers look up gradients by ID number and search for assets featuring specific colors or gradients.

5. Unsplash API

UI designers occasionally need stock photos. But it’s inconvenient to have to go to a web browser every time an image is needed. UI developers should have an image API like the Unsplash API as part of their toolkit, partially because of the quality of its images and partially because of its extreme customizability.

6. Figma API

Figma API bridges the gap between design and development. It lets developers access files, design tokens, styles, and assets directly from Figma, a collaborative interface design platform. This helps to guarantee consistency across all projects and platforms. It’s also a popular pick simply due to Figma’s popularity among designers of all kinds.

7. Airtable API

Every frontend needs a backend. This makes a dependable database API mandatory for UI designers and developers. The Airtable API is a popular choice, as it provides a reliable database without becoming overly technical. It essentially turns a spreadsheet into a database, making it ideal for developers who just need to interact with their data without having to become fully-fledged database architects and data engineers.

8. Google Analytics API

Good designers do their best to remove the guesswork from as much of their design process as possible. The Google Analytics API is an important link in this equation, as it can observe custom data like clickthrough and conversion rates. Such information helps developers and designers know precisely how users are interacting with their designs. Developers can even create custom dashboards using data from the Google Analytics API, providing even greater insights into how users are interacting with the UI.

9. Dropbox API

Designers need to send files back and forth constantly. This makes a file-sharing API like the Dropbox API a vital part of a UI developer’s stack. Dropbox is a popular pick for a file-sharing API due to its longevity and popularity. Millions of users all over the world have used Dropbox for nearly two decades, and it’s incorporated into countless applications to provide storage functions. Additionally, if you want to have your employees, clients, and others sign documents, the Dropbox API can enable this as well.

10. Sketch API

The Sketch API is one of the most versatile tools a UI designer could hope for. It lets Sketch users interact with the document object models (DOM) of Sketch files, which makes it possible for designers to do everything from creating or modifying shapes to creating new layers. It also supports custom plugin development, which lets teams customize their own workflow directly from the development environment. Add in the ability to automate repetitive tasks, and you’ve got an indispensable UI API.

Honorable Mentions

• Material UI API is an impressive API for frontend designers. It offers premade React-based UI components that still allow full customization of every element and layer. It also supports consistent theming. The Materia UI API could be useful for developers and designers who don’t want to waste time remaking common elements.

10 APIs for UI Designers: A Quick Comparison

Final Thoughts on APIs for UI Design

UI design is about more than making something look good. It’s about creating tools that are usable, useful, reliable, and consistent for your customers and users. Delivering the best experience possible, reliably and consistently, involves eliminating as much guesswork as possible, which is where APIs like the Google Analytics API come in. On the design of things, there’s Figma, Sketch, and Material UI. Other APIs like the Google Fonts API, Unsplash API, and the Noun Project API let you retrieve, modify, store, and sort design assets from your programming environment. Finally, the Color API and Color Gradient API let developers style their UI directly from the API.