Public APIs Developers Can Use in Their Projects

As a developer, integrating external data and services into your applications can add powerful functionality and greatly enhance the user experience. Public APIs provide a convenient way to access this external data without having to build everything from the ground up yourself.

In this guide, we‘ll take an in-depth look at what public APIs are, why they are useful for developers, some challenges to be aware of, and tips for choosing the right ones for your projects. We‘ll also highlight many popular public API examples that you can start using in your applications today.

What Are Public APIs?

An Application Programming Interface (API) defines the rules and protocols for how different software applications can communicate with each other. A public API is an interface that has been made publicly available for all developers to access.

Public APIs act as a bridge, allowing your applications to interact with and retrieve data from external sources. This could be anything from financial data and weather reports to social media feeds and mapping services. The API provides a structured way for your application to request this data and integrate it into your own services.

Types of Public APIs

There are several different flavors of public APIs that you may encounter:

REST APIs

RESTful APIs are the most common type of public APIs. REST stands for "REpresentational State Transfer" and defines a set of architectural principles for designing networked applications.

REST APIs expose a set of dedicated URLs as endpoints to interact with the underlying data. Developers make HTTP requests to these URLs using standard methods like GET, POST, PUT and DELETE to retrieve, submit, update and remove data respectively.

The data is typically returned in JSON or XML format for easy parsing and integration into your application. Some popular examples of REST APIs include the Twitter API for accessing tweet data and the Stripe API for processing payments.

SOAP APIs

SOAP (Simple Object Access Protocol) is an older, more complex API protocol that uses XML for sending and receiving data. While it has been largely superseded by REST in most public API implementations, some legacy applications may still utilize SOAP.

SOAP APIs often provide more advanced security and transactional compliance features compared to REST. However, the overhead of the XML parsing can also result in slower performance.

GraphQL APIs

GraphQL is a more modern query language and runtime for APIs. Developed internally by Facebook, it was released publicly in 2015.

The key advantage of GraphQL is that it allows the client to specify exactly what data it needs. Instead of the server determining the data returned, the client can query for the exact fields it requires. This leads to more efficient data retrieval and minimizes redundant data transfer.

Well-known examples of GraphQL APIs include the GitHub GraphQL API and Shopify‘s Storefront API.

Webhooks

Webhooks, sometimes referred to as "reverse APIs", allow you to receive real-time HTTP notifications from the server whenever a specific event occurs. Instead of constantly polling the API to check for new data, your application simply subscribes to the relevant events and will automatically receive a payload to a dedicated URL whenever they are triggered.

This is particularly useful for integrating real-time functionality like instant payment notifications, tracking delivery status updates, or broadcasting updates to multiple clients.

Websockets

If you need true real-time, bidirectional communication between the client and server, websockets are the way to go. While not strictly an API protocol itself, websockets provide an important capability that many public APIs utilize.

Once a websocket connection is established, both the client and server can send messages to each other at any time, without the need for an explicit request/response cycle like traditional HTTP. This is ideal for applications like multi-player games, collaborative tools, chat applications, or real-time data display.

Benefits of Public APIs for Developers

So why should you consider integrating public APIs into your applications? There are several compelling reasons:

Save Development Time and Resources

Integrating an existing public API is almost always faster than trying to build that capability yourself from scratch. With a well-documented API, you can have integrated a totally new feature or dataset into your application within a matter of hours.

This allows you to focus your development efforts on your application‘s core functionality and unique value proposition, rather than reinventing the wheel by coding standard capabilities that have already been implemented by someone else.

Add New Functionalities

Public APIs empower you to easily add completely new capabilities to your applications that would have been infeasible to develop yourself.

For example, integrating a mapping API can instantly give your app sophisticated location-based capabilities. Utilizing a public machine learning API can allow you to add intelligent prediction features without needing to build your own models. The sky‘s the limit in terms of added functionality.

Retrieve Comprehensive Datasets

Many public APIs provide access to comprehensive datasets that have been painstakingly compiled. This could be anything from detailed financial market data to movie reviews to government spending records.

Integrating these datasets into your own applications opens up huge possibilities for unique user experiences, deep insights and compelling data visualizations. With the hard work of data collection and maintenance abstracted away behind the API, you‘re free to be creative in how you manipulate and display that data within your apps.

Improve Development Efficiency

Public APIs provide standardized, reusable building blocks that you can leverage across multiple development projects. Once you‘ve built the integration with the API once, you can reproduce that capability across your whole range of products.

This greatly improves the efficiency and velocity of your development process. It‘s like having a box of pre-assembled Lego blocks at your disposal, compared to building everything out of raw bricks.

Challenges of Using Public APIs

While integrating public APIs into your stack provides a host of advantages, there are some important challenges and considerations to keep in mind:

Security and Data Privacy

If you‘re working with sensitive user data or proprietary business information, you need to be extra careful about which public APIs you choose to integrate. Make sure to only utilize APIs from reputable providers that have robust security and encryption practices in place.

Carefully review the API‘s privacy policy and terms of service to understand how they safeguard and utilize any data passing through their servers. Ensure that you are fully compliant with all relevant privacy protection regulations like GDPR and HIPAA.

Reliance on External Services

When integrating an external API into your application, you‘re introducing a dependency on a service that is outside of your direct control. If the API experiences downtime or service interruptions, that dependent functionality within your application will also go down.

While all reputable public APIs strive to maintain high uptime and reliability, no provider can guarantee 100% availability. Be sure to set clear user expectations around this and build in graceful error handling for API issues.

You may also want to build in a backup provider or failover mechanism if the API is absolutely mission-critical to your app. Caching API responses on your end can also help mitigate the impact of temporary outages.

Rate Limits and Pricing

Public API providers need to set limits on the volume of requests to ensure the stability of their service and infrastructure. This is typically defined in terms of the number of API calls your application can make within a certain time period, like 1,000 requests per hour.

For high volume applications, these rate limits can quickly become a bottleneck. Carefully examine the rate limit policies and pricing tiers for your required usage. Some APIs may offer paid plans for higher limits.

It‘s important to code your application to respect these rate limits and gracefully handle cases where you may reach or exceed them. You can also implement techniques like caching and request consolidation to optimize your usage efficiency.

Documentation and Support

The usefulness and ease of integration of a public API is heavily dependent on the quality of its documentation and the responsiveness of its support channels. Ideally, the API will provide detailed, easy-to-follow guides with plenty of code examples for the most common use cases.

Test out the API support by reaching out with a question or two before committing to integration. Responsive, helpful support can make a world of difference when you run into any snags during the development process.

Compatibility Issues

Make sure that the public API you choose provides support for your application‘s technology stack and codebase. Check what programming languages, frameworks and environments the API provides official libraries or SDKs for.

While most modern APIs strive for language-agnostic design, there may be certain languages or frameworks that are better documented and supported than others. If official support is not provided for your specific stack, check if there are any well-maintained third party libraries or wrappers that you can utilize.

Choosing the Right Public APIs

With so many different public APIs out there, how do you go about choosing the right ones for your application? Here are some key factors to consider:

Functionality Alignment

Make sure that the API actually provides the specific capabilities and datasets that your application requires. Carefully review the API documentation to understand the full scope of what‘s available and any specific limitations or edge cases.

Ideally, look for an API that offers the flexibility to support your requirements now as well as future growth and expansion down the line. Consider any additional nice-to-have features that could further enhance the user experience.

Reliability and Performance

The API needs to be highly reliable and responsive in order to provide a seamless experience for your application‘s users. Look for APIs with clear uptime guarantees and transparent system status pages.

Test the API response times during your evaluation period to ensure that performance is satisfactory. Well-designed APIs will provide mechanisms like caching and CDN support to optimize the speed of data retrieval.

Security and Compliance

Security is paramount when integrating third-party services into your stack. Make sure that the API utilizes encryption for all data transmission and has strong access controls in place.

If you‘re working with sensitive data, look for APIs that are compliant with all relevant regulatory requirements like GDPR, HIPAA, PCI-DSS, etc. Many industries have specific compliance needs that will dictate which APIs are suitable.

Documentation and Ease of Use

Well-documented APIs with clear, detailed usage guides and code examples are a joy to work with. They make the integration process smooth and painless, allowing you to go from concept to implementation in record time.

Look for APIs that provide documentation in a clean, navigable format with plenty of practical advice and best practices. Bonus points for interactive API explorers and step-by-step tutorials to get you up and running quickly.

Pricing and Support

Consider the pricing model and tiers for the API, making sure that it aligns with your usage needs and budget. Don‘t forget to factor in any additional costs for support or premium features.

Speaking of support, good documentation is one thing, but responsive human assistance is priceless when you run into any issues or advanced implementation challenges. Look for APIs with a proven track record of timely, helpful support. The API providers should be invested in helping their developer community succeed.

Developer Ecosystem and Feedback

Take a look at the broader ecosystem and community around the API. Is there an active forum or Q&A knowledge base where developers are sharing tips and collaborating on solutions? Are there regular hackathons, webinars, or local meetups to get involved with?

Check out independent online reviews and posts to get a sense of other developers‘ experiences working with the API. While every use case is unique, consistently positive or negative feedback can be very telling. Reach out to your developer network for trusted recommendations to help narrow down your list.

Popular Public API Examples

To give you a taste of the vast variety of capabilities you can add to your applications, here are some of the most popular and powerful public APIs available today:

Weather APIs

Integrate real-time weather data and forecasts into your applications with APIs like OpenWeatherMap, Dark Sky or Weather Underground.

Mapping APIs

Add interactive maps, geocoding, and directions to your apps with the Google Maps API, MapBox API or OpenStreetMap API.

Financial APIs

Build in payment processing and financial data reporting with APIs like Stripe, PayPal, or Plaid.

Social Media APIs

Integrate your apps with the most popular social networks using the Twitter API, Facebook Graph API, or Instagram API.

E-commerce APIs

Build powerful online stores and shopping carts with e-commerce focused APIs like Shopify, WooCommerce and Magento.

Government APIs

Access authoritative public data sets from government organizations via APIs like Data.gov, USASpending.gov and the US Census Bureau API.

Machine Learning APIs

Leverage the power of artificial intelligence in your apps with APIs like IBM Watson, Google Cloud Vision, or Amazon Rekognition.

News APIs

Integrate live news feeds and headlines into your applications from sources like the New York Times API, News API or Reuters API.

Video APIs

Add video capabilities to your apps with APIs from YouTube, Vimeo, or Twitch. Livestream events, manage playlists and channels, and analyze video metadata.

Music APIs

Build music apps that can search tracks, create playlists, and provide recommendations using APIs like Spotify, SoundCloud or Apple Music.

Conclusion

We‘ve covered a lot of ground in this guide to public APIs for developers. Hopefully you now have a clear understanding of what public APIs are, why they are so useful, and how to effectively evaluate and integrate them into your applications.

As you‘ve seen from the wide variety of API examples across different domains, public APIs open up a world of possibilities to enhance your applications and supercharge your development process. By leveraging these existing building blocks, you can create more powerful, full-featured applications in a fraction of the time.

As you explore the public API landscape, remember to carefully consider the reliability, security, pricing and support for any APIs you‘re looking to adopt. Make sure to allocate enough time for thorough testing and integration planning to ensure a smooth roll out.

Most importantly, don‘t be afraid to experiment and get creative with your API integrations. Public APIs provide a nearly limitless frontier for innovation and differentiation within your applications. Combine multiple APIs together in unique ways to create something truly exceptional for your users.

So dive in and start exploring the exciting possibilities that public APIs open up for your development projects. The only limit is your imagination!