Risks with Using External APIs: A Tech Guide to Staying Safe

External APIs (Application Programming Interfaces) are a powerful tool for developers, letting apps talk to each other and share data or services seamlessly. Whether you’re building a weather app that pulls data from a weather API or an e-commerce site using a payment API like Stripe, external APIs can save you time and effort. But they come with risks that can impact your project if you’re not careful. With the growing reliance on APIs in cloud-based and microservices architectures, understanding these risks is more important than ever. In this article, we’ll explore the main risks of using external APIs, how they can affect your tech projects, and tips to mitigate them. Let’s dive in and uncover the potential pitfalls of external APIs!

What Are External APIs and Why Use Them?

An external API is a set of rules and tools that lets your app communicate with a third-party service over the internet. For example, if you’re building a travel app, you might use the Google Maps API to show locations or the Skyscanner API to fetch flight prices. These APIs let you access features or data that you don’t have to build yourself, saving you time and resources. They’re widely used in software development because they allow you to add complex functionality—like payment processing, geolocation, or social media integration—without starting from scratch.

But while external APIs are convenient, they introduce risks because you’re relying on a service you don’t control. If the API provider changes their service, goes down, or has security issues, your app could suffer. Understanding these risks can help you plan better and protect your project from unexpected problems. Let’s break down the main risks of using external APIs and how they might affect your work.

Risk 1: Downtime and Reliability Issues

One of the biggest risks with external APIs is downtime. Since you’re relying on a third-party service, if their servers go down, your app might stop working properly. For example, if your e-commerce app uses a payment API like PayPal, and PayPal’s servers are down, your customers won’t be able to check out. This can lead to lost sales and frustrated users.

Downtime can happen for many reasons—server outages, maintenance, or even cyberattacks on the API provider. In 2023, a major outage at Twilio, a popular communication API provider, disrupted thousands of apps that relied on its SMS and voice services. If your app depends heavily on an external API, you’re at the mercy of their reliability. Even APIs from big companies like Google or AWS can experience outages, though they’re usually rare.

To mitigate this risk, check the API provider’s uptime history—many publish their service-level agreements (SLAs) promising a certain percentage of uptime, like 99.9%. You can also build fallback options into your app. For instance, if a weather API fails, you might show cached data or a message explaining the issue to users. Planning for downtime ensures your app stays functional even when the API doesn’t.

Risk 2: Security and Privacy Concerns

Security is a major concern when using external APIs, as you’re sharing data with a third-party service. If the API provider has weak security practices, your app—and your users—could be at risk. For example, if you’re using an API to process user logins, and the API gets hacked, attackers might steal sensitive data like email addresses or passwords. In 2024, a data breach at a popular marketing API exposed user data for thousands of apps, highlighting how API vulnerabilities can ripple outward.

Another issue is privacy compliance. If your app handles user data, you need to follow laws like GDPR (in Europe) or CCPA (in California). But if the API provider doesn’t comply with these regulations, you could be held responsible for any violations. For instance, if a third-party analytics API collects user data without proper consent, your app might face fines or legal trouble.

To reduce security risks, choose API providers with strong security practices—look for HTTPS encryption, regular security audits, and compliance certifications like ISO 27001. Also, limit the data you share with the API to only what’s necessary. For example, if you’re using a mapping API, don’t send user info that isn’t needed for the map feature. Finally, use API keys or OAuth for authentication to ensure only authorized requests are made, and monitor your API usage for unusual activity.

Risk 3: Unexpected Changes or Deprecation

External APIs can change without warning, which can break your app. API providers might update their endpoints, change how data is formatted, or even shut down the API entirely—a process called deprecation. For example, in 2022, Google deprecated its older Hangouts API, forcing developers to migrate to a new version or find alternatives. If your app isn’t prepared for these changes, it could stop working overnight.

Even small changes can cause big problems. If a weather API you’re using changes its response format from JSON to XML, your app might not be able to parse the data correctly, leading to errors. These updates often come with little notice, especially from smaller providers who may not prioritize developer communication.

To manage this risk, keep an eye on the API provider’s changelog or developer blog for updates. Many providers, like Stripe or Twitter, have email notifications for API changes. You can also version your API calls—most providers offer versioned endpoints (e.g., /v1/endpoint) to ensure stability. Finally, have a backup plan, like switching to a different API or building a workaround, in case the API gets deprecated.

Risk 4: Performance and Latency Issues

Using an external API can slow down your app if the API’s performance isn’t up to par. Every API call involves sending a request over the internet, waiting for a response, and processing the data. If the API is slow, your app will be too. For example, if you’re using a geolocation API to show a user’s location on a map, and the API takes 5 seconds to respond, your users will have to wait, which can hurt their experience.

Latency can also vary depending on the API provider’s server location. If your app’s users are in Europe, but the API’s servers are in the US, the distance can add delays. High traffic on the API provider’s end can also cause slowdowns—think of a payment API struggling during a Black Friday sale.

To minimize performance risks, test the API’s speed during development using tools like Postman or curl to measure response times. Choose providers with servers close to your user base, or use a content delivery network (CDN) to cache API responses. You can also implement caching on your end—store frequently used API data locally so you don’t need to call the API every time. For example, if your app shows weather data, cache the data for an hour to reduce API calls.

Risk 5: Cost Overruns and Rate Limits

Many external APIs aren’t free, and costs can add up quickly if you’re not careful. Most APIs use a pricing model based on usage, like charging per API call or offering a tiered subscription. For instance, the Google Maps API charges based on the number of map loads or geocoding requests. If your app suddenly gets more users, your API usage—and your bill—could spike unexpectedly.

Rate limits are another issue. APIs often cap how many requests you can make in a given time—like 1,000 calls per hour. If you exceed this limit, the API will block your requests, causing your app to fail. For example, if you’re using a social media API to pull tweets, and your app goes viral, you might hit the rate limit and lose access to the API temporarily.

To avoid cost overruns, monitor your API usage closely using dashboards provided by the API provider, like AWS’s billing console or Stripe’s usage tracker. Set budget alerts to warn you if costs get too high, and optimize your app to make fewer API calls—caching and batching requests can help. For rate limits, design your app to handle them gracefully, like showing an error message to users or queuing requests to stay within the limit.

Risk 6: Dependency and Vendor Lock-In

When you use an external API, you become dependent on the provider, which can lead to vendor lock-in. This means your app is tied to their service, making it hard to switch to another provider if needed. For example, if you build your app around the Twilio API for SMS, and Twilio raises prices or shuts down, you’ll need to rewrite parts of your app to use a different API, which takes time and effort.

Vendor lock-in can also limit your flexibility. If the API provider doesn’t support a new feature you need, you’re stuck until they add it—or you’ll have to find a new provider and migrate. This dependency can slow down your development and make your app less adaptable to changes.

To reduce dependency, design your app with flexibility in mind. Use abstraction layers—like a custom wrapper around the API—so you can swap out providers without rewriting everything. For example, if you’re using a payment API, create a generic payment module in your app that can work with Stripe, PayPal, or another provider with minimal changes. Also, choose APIs with open standards or wide adoption, as they’re less likely to disappear suddenly.

Tips to Mitigate Risks When Using External APIs

Here are some practical tips to stay safe when using external APIs in your projects:

• Research the Provider: Before choosing an API, check their reputation, uptime history, and security practices. Look for reviews from other developers on forums like Stack Overflow or Reddit to see if they’ve had issues.
• Test Thoroughly: Test the API during development to understand its performance, reliability, and error handling. Use tools like Postman to simulate API calls and see how the API behaves under different conditions.
• Monitor Usage: Keep an eye on your API usage with tools like the provider’s dashboard or third-party monitoring services. Set alerts for rate limits, costs, and unusual activity to catch problems early.
• Plan for Failures: Build fallbacks into your app, like caching data or showing error messages, so it can handle API downtime or rate limits without crashing.
• Document Everything: Keep detailed documentation of how you’re using the API, including endpoints, authentication methods, and fallback plans. This makes it easier to troubleshoot issues or switch providers later.
• Stay Updated: Follow the API provider’s updates via their blog, changelog, or email notifications. This helps you prepare for changes or deprecations before they affect your app.

By following these tips, you can use external APIs confidently, knowing you’ve planned for potential risks and can handle them if they arise.

A Real-World Example of API Risks

Let’s look at an example to see these risks in action. Imagine you’re building a fitness app that uses the Fitbit API to pull users’ step counts. One day, Fitbit’s servers go down (downtime risk), and your app can’t show step data, frustrating users. Later, Fitbit gets hacked (security risk), exposing user data and putting your app at risk of legal issues. Then, Fitbit updates its API, changing the data format (change risk), and your app breaks because it can’t parse the new format. Meanwhile, your app’s user base grows, hitting Fitbit’s rate limit (cost/rate limit risk), and you’re charged extra fees. Finally, Fitbit raises prices, but you’re locked into their service (dependency risk), forcing you to either pay more or rewrite your app for another API. This scenario shows how API risks can pile up, but with proper planning—like caching data, monitoring usage, and using abstraction layers—you can avoid these pitfalls. (Fitbit was just an example - I don't imply that this happens to Fitbit).

Final Thoughts on Using External APIs Safely

External APIs are a game-changer for developers, letting you add powerful features to your app without building everything from scratch. But they come with risks like downtime, security issues, unexpected changes, performance problems, cost overruns, and dependency. By understanding these risks and taking steps to mitigate them—researching providers, testing thoroughly, monitoring usage, and planning for failures—you can use APIs safely and effectively. Whether you’re building a small app or a large-scale system, being aware of these risks will help you create more reliable, secure, and cost-effective applications. So, the next time you integrate an external API, take a moment to plan ahead—it’ll save you a lot of headaches down the road!

Resources for Further Learning

Want to learn more about using external APIs safely and managing their risks? Check out these helpful resources:

Books on Amazon:

APIs: A Strategy Guide by Daniel Jacobson, Greg Brail, and Dan Woods (Buy book - Affiliate link) – A great book on API design and management, including risk mitigation.

Designing Web APIs by Brenda Jin, Saurabh Sahni, and Amir Shevat (Buy book - Affiliate link) – Covers best practices for working with APIs, with a focus on security and reliability.

RESTful API Design by Matthias Biehl (Buy book - Affiliate link) – Explores API design principles and how to handle risks like changes and deprecation.

YouTube Videos:

Top 12 Tips For API Security

Understanding The Fundamentals of API Security | How APIs are Attacked and How to Secure Them

Unmanaged APIs are hurting your productivity and security. Start managing your sprawl with API Hub

Using the latest version of external components - Needs attention

Most software applications do use components that are not created by the software team; these could be components created by other teams within the organization, or by using components created by other organizations. For so many different functions, it is not required that the team try to do everything on their own; for example, you could consider many different types of parsers, or system access components, or image manipulation components, or video codecs / decoders, etc. In all of these, these are specialized components created by people far more competent in these areas; it would always make sense to use these components rather than try to replicate such software within our own application.
When your software is larger, there would be more such components that are in use which are created by other parties. Over a period of time, it gets to be a task to track all such components. I have experience where we used such components the first time many years back, pay for using the component at every new version of the application, and the number of such components that are in use is well over 50 within the application (some of those are free, others are paid with minimal charges, and some can be pretty expensive - some of the specialised video codecs can be pretty expensive, although one cannot do business in the video area without using these codecs in order to look professional).
Just like our software is updated with every version with new features and defects, even the components that we use also get new versions. In many cases, we could still continue using the older components since the newer version does not promise any new features that we need, and we can avoid the overhead of trying to incorporate a new version. However, it is still required to monitor these external components to ensure that we know the reasons why the new component has been released.
In many cases, there may have been some critical defects found in the component which required a new version to be released. In such a case, we should need to evaluate the defects that were found to determine whether it is required for us to take the new version. In some cases, the defects could be in a section of the component that we do not use, and hence we could still continue to use the old component. But in many cases, the defects are serious enough that it could pose a risk to the software application unless the new version of the component has been taken. However, taking the component will have an overhead, since other changes that have been implemented in the component would need to be evaluated and testing done to ensure that no other impact is caused due to these changes.
This whole process of ensuring a watch on these components is troublesome and takes time and effort, but it is essential. One would not want to release a software that integrates an older version of the component which has some serious risk. This can have further impact, and in some cases, the external component provider mandates that the newer version of the component has to be used.

Ensuring coordination with respect to 3rd party icons such as from Facebook / Youtube .. (contd)

I wrote a post about this topic in a previous post (using icons from external services such as Facebook or Twitter). One of the unsaid conclusions from the previous post was that it is essential that such planning be done well in advance, so that one does not run into issues near the end of the schedule - tracking of such items where multiple parties are involved can be time consuming and frustrating when getting into the ending stage of a schedule. So what are some of the points to keep involved when dealing with using icons from 3rd party services such as Youtube, Facebook and Twitter:
- If you have used the icons in a previous version of the software, ensure that when you get into a new version of the software, you verify about whether there is a requirement to update the icon. If not, then it would be easiest to just ensure that you continue with the old icon.
- When you are doing some re-design on your end, and need to get a different icon, many of these have multiple icons available with different sizes also available for use. However, if none of these icons really fit into the UI of your application, things can get tricky. The terms and conditions of most of these services do not allow you to use an icon other than the ones that they have supplied, so modify your UI accordingly.
- If there are multiple products within the organization that use these services, then it would make sense to ensure that these products collaborate with each other to understand their use of these services. We had a classic case where one team had a relationship with the product manager of one of these services (through one of the team-members, and this contact helped in refining the use of some icons).
- Make sure that the legal team is well conversant with the usage of these icons (and also overall with the incorporation of connectivity with these services). Even though these services seem present everywhere, they do come with their terms and conditions, which need to be met by the products that are interacting with these services.
- Most of these services have an active development community. It is important to ensure that atleast one of the development team members is on this community since these communities are the first places to be notified when there are any change in policies of the external service provider. This is pretty important. We were connecting with one of these services, and then it turned out that there was a notification about a change in the API that was being used, and we did not know about this; when did we get to know ? When our connectivity to the service was lost.

Ensuring coordination with respect to 3rd party icons such as from Facebook / Youtube ..

The process of software product development is a complex one, with a number of different items to manage. In addition to the many internal complexities that need to be managed (requirements / development and testing schedules, etc), there are a whole load of external dependencies that need to be managed, and the amount of complications involved in these external dependencies are greater than than those of the internal kind. One of the complications that need to be handled has increased with the usage of more and more 3rd party services. With the increasing use of social networks by people all over the world, they being Twitter, Facebook, Flickr, Google+, and numerous other social and sharing sites, life is more complicated now.
One cannot build applications without the connection with such sharing sites, but the actual logistics of getting this done can be complex. One of these areas revolve around all the icons and others used in the application. Now, for the most part, most applications with a large number of user interfaces use their own customs icons and graphics, these having been made to seem to fit with the application (in terms of the image that the application seeks to present, the customer profile that it tries to fit, as well as the functionality that is being done in the application - an application that is dealing with money or finances would have more icons that have some sort of representation of money or cash, while applications dealing with images would show more of cameras or images, etc). Another use of these custom icons is that they present the same set even if the application is installed on Windows or on the Mac (while the application system icons on these different OS's are very different).
However, when interfacing with these 3rd party icons, there needs to be careful coordination with the team that is developing the custom icons. As part of the public API's available for most of these networks, they also have a list of icons that client applications need to use, and in some cases, the icon may drastically vary from the icons used in the application. It is typically not possible to get variations in the icons provided by these 3rd party services, although some of them will provide multiple icon sets at different sizes to ensure that one of them is suitable, but that may not be the case. Further, the team designing the custom icons may not be aware that there is a legal requirement to use only the service icons, and they should be kept informed so that they do not try to develop customs icons for these networks when only the service provided icons can be used.
In addition, if the icons provided by the services are striking on their own and different from those in the application, it would help if the designer team already knows this in advance, and hence can ensure that the icon set that they are designing for the application is made in a way that the service provided icons fit with the service. But, from time to time, these 3rd party services also go in for a rebranding, and require all clients using their services to also change the icons that they are using, which means that somebody needs to keep track of communication from the external services regarding their branding and icons.