These days, businesses have a whole heap of APIs and apps to look after. To prioritize reliability, maximize uptime, and avoid service disruption and potential reputational damage, API health checks are part of a proactive approach to monitoring the overall health of your APIs.
What is an API health check?
An API health check is a way to check the operational status of an API. It is a monitoring method that can alert you when something isn’t functioning as it should. You can set up an API health check monitoring and system for each API, view the results on a dashboard and receive alerts for unexpected results. This proactive approach to diagnostics means you can respond to any issues in a timely fashion and maintain superior reliability and uptime.
What do API health checks monitor?
You can monitor and analyze anything that could prevent your API from servicing incoming requests in the way that it should. For example, you could monitor:
| What you can monitor | How you can monitor it |
| Availability | Send regular requests to API endpoints to verify they are accessible |
| Functionality | Send requests using specific inputs to check these return the expected responses |
| Performance | Track response times, measuring the latency to identify any slowdowns or performance bottlenecks |
| Error detection and recovery | Log errors and exceptions to identify abnormal behavior |
Should any of the checks return unexpected results, the health check service can alert you, so you can take swift remedial action before the issues escalate and impact your user experience (UX).
Use cases for API health monitoring
API health monitoring meets a wide range of needs. When you provide applications that rely on APIs, for example, health checks ensure that the underlying API infrastructure is functioning as it should so that your apps can do the same.
An API gateway health check system can be particularly useful in complex environments. Let’s say you use a microservices API gateway and are growing the number of microservices you use. In essence, the more you use, the more complex things get. With plenty to keep an eye on, automating the health monitoring of your microservice API endpoints means you can take a proactive approach to catching issues early.
You can also use health check data to optimize the UX of your APIs and the applications that sit on top of them. For example, if you identify performance bottlenecks as part of an API health check, you can make changes that will iron out those bottlenecks and contribute to enhanced performance.
Benefits of API health checks
Monitoring the health of your APIs helps you minimize downtime, identify and resolve issues more proactively and optimize performance, delivering a superior UX. When you configure your checks to maintain a healthy API in this way, you can implement remedial action before issues escalate, keeping you in control.
Some of the key benefits of API health checks include:
Proactive issue detection
Detecting issues proactively provides you with an early warning system for performance degradation. You can resolve issues that might impact uptime or reliability before they affect your users. This helps keep your customer churn rate under control.
Your API health checks can also flag up dependency issues across interconnected services. This means your health checks don’t only look after your API but help you maintain reliability of any server or service that depends on the API.
Operational excellence
Every business can reap the rewards of operational excellence, which can enhance everything from its reputation to its financial returns. API health checks can support the achievement of operational excellence through:
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- Reduced mean time to detection: Automated monitoring can result in the faster identification of incidents, meaning you can discover and fix problems before they turn into bigger problems that your customers notice.
- Improved incident response times: Sufficiently detailed health metrics mean you can not only uncover issues faster, but also pinpoint what has gone wrong and what you need to rectify as speedily as possible.
- Better capacity planning: You can use historical health check data to project future trends and resource requirements, ensuring accurate capacity planning and budget forecasting.
Continuous monitoring of the above (and other areas of your API’s health) supports enhanced system reliability. It helps you deliver a standard of operational excellence that ensures customers trust in your business and your products.
Cost optimization
API health checks can save you money in numerous ways. For example, your diagnostics can help you analyze how effective your resource allocation is. This can empower you to respond proactively to wasted resources, optimizing them to keep tight control of your costs. You can also bring down your maintenance costs, through proactive and preventative issue detection.
These deliver knock-on cost savings too. Faster issue response times mean reduced downtime for your API, which results in less lost revenue. It also results in a decrease in costly emergency response situations, further bringing down your overall costs.
Business continuity
With the right approach to API health checks, you can identify resource bottlenecks before they cause system failures. As a result, your API service is more reliable. Your health check tools thus support business continuity, along with easier maintenance of your service level agreements and improved customer retention. This preserves your brand reputation and promotes enhanced stakeholder confidence – as does the ability to avoid major outages thanks to your proactive and transparent health monitoring and alerting strategy.
Security and compliance
Monitoring the health of your API closely and enhancing security through regular endpoint verification can alert you in real-time to unusual behavior patterns and other anomalies that could indicate security threats. This supports greater security for your API while delivering an audit trail of system health and availability. The result is not just reputational protection for your business, but also a happier relationship with your regulators, thanks to enhanced compliance with regulatory monitoring requirements.
User experience impact
A proactive approach to API health checks can help deliver consistent service and application availability for your end users, with fewer disruptions and faster resolution of potential issues. The result? A superior user experience that promotes positive word-of-mouth in relation to your product.
Types of API health checks
Some health checks are to monitor a very specific or basic element of your API, while others run deeper, diving below the service to component-level. Each of these has its uses, so let’s look at a few examples of the types of API health checks you can undertake.
Liveness checks: Basic operational status
API liveness checks tell you if an API is currently running. If the API is operational, a liveness check should return a “healthy” status, confirming that the API is live.
Readiness checks: Service availability
Readiness checks tell you if an API is ready to receive requests. This goes beyond mere liveness; it determines whether your API is fully initialized and ready to handle traffic.
Deep health checks: Component-level status
When you want to dive deep into the health of your API, a component-level status check is the way to do it. This comprehensive approach to monitoring looks at each individual component of an API system. It can check the health of databases, caches, internal functions, external services and more, providing you with powerful insights into what’s going on below the surface of your API. This is a powerful tool for proactively identifying issues and for ensuring the optimal functioning of your API.
How do you health check microservices?
Health checking microservices is simple. You just need a health check API endpoint for each service. You can then check whatever metrics are most relevant to that service – memory consumption, database connection, response time and so on. You can use a dashboard to display the results and an alert system to immediately flag up any issues.
As well as monitoring the operational health of individual microservices, API health checks can also verify each service’s ability to connect to dependent services. This downstream operation status monitoring aids you in spotting issues early.
Health check implementation examples
Many modern enterprises have more than one type of API. This means you may need to perform health checks for different API formats and protocols to ensure your services and business as a whole are functioning as they should. Let’s consider a few common API health check implementation examples.
RESTful API health check
Usually, health checking a REST API involves creating a health check endpoint. This endpoint returns the status of the service, using JSON format (see the best practices section below for more on this). When you send a simple GET request to the health check endpoint, it will return real-time insights into the operational status of your API. If the response contains anything unexpected, it’s time for further checks.
GraphQL health check
A basic GraphQL health check is a little more nuanced than a basic REST endpoint check. With a GraphQL API health check, you need to ensure the schema and resolves are correctly loaded and that they can handle queries.
gRPC health check
The “RPC” in gRPC stands for “remote procedure call” and means that gRPC API health checks take a different approach to those for REST and GraphQL APIs, using a health check request call. You can use these types of health checks for gRPC APIs to monitor the health of microservices as well as the availability of the API itself.
Asynchronous API health check
Asynchronous APIs need a different approach to health checks, as they don’t always respond immediately to requests, as synchronous APIs do. This means async API health checks need to factor in elements such as pending jobs, queues and background tasks. Rather than checking the completion of tasks, async health checks need to ascertain the API is capable of processing tasks. This is achieved by verifying the overall health of the queue, checking the job processing mechanism, monitoring task status and so on.
Database connection health check
As many APIs connect to databases – and rely on those connections for services to function correctly – you’ll likely want to undertake database connection health checks, as well as checking the APIs themselves. Database connection checks verify that your API will perform as it should when retrieving or writing data.
The form of your database checks will depend on your API types. For a RESTful API, for example, you could use a GET request to check the database’s connection health.
What is the difference between API health check and API ping?
You can use pings to check your APIs are running and receiving HTTP requests. If you get a successful ping response, you know your API is receiving requests. An API health check, however, can tell you much more. It not only shows that your API is running but can assure you that all the critical parts of it are functioning as expected – and help you home in on any that aren’t.
API health check best practices
Implement these best practices to get the best out of your health check services.
Automate API health checks
Automating your API health checks means you can implement continuous monitoring without the need for manual intervention. You can automate regular checks, checks in response to predefined triggers and alerts for when a check fails or returns an unexpected result.
Check API health as frequently as possible
The more frequent your checks, the more likely you are to catch any issues before they escalate. By identifying issues in real-time, you can minimize downtime. Just bear in mind that health checks will impose a load on your API infrastructure.
Disable cache
API health checks work by monitoring responses. However, cached responses can mask underlying issues and produce false positives. As such, disable caching mechanisms during health checks.
Response time matters
There are various ways to get the best out of response time checks. You’ll need to set response time thresholds to define what good looks like for your APIs. You can also bolster the impact of response time checks by analyzing response time data over time. Doing so can help you identify performance bottlenecks and trends, plus bring longer-term performance degradation issues to light.
JSON response
It’s a good idea to use a standardized JSON structure to deliver your health check status information and associated details. JSON’s human readability, flexibility, extensibility, efficient serialization and deserialization and broad compatibility make it ideal. Configuring your health check endpoint to return responses in this format means you can receive clear, concise information about the health of your APIs’ critical components and the status of their dependencies.
Response status code
The response status codes that you use will make it easy to verify the status of the API you are checking. For example, you can use a success status code (2xx) to indicate that an API is functioning as it should and an error status code (4xx or 5xx) to indicate that it isn’t.
Some examples of response status codes include:
| Status code | Meaning | Description |
| 200 OK | Healthy | The API is operational and functioning normally (with a couple of exceptions – remember that, for GraphQL environments, 200 is not always ok). |
| 202 Accepted | Request accepted, processing pending | Although the health check has returned an “accepted” status, the task has not completed within the expected timeframe, which could indicate a sluggish background process. |
| 204 No Content | Health check incomplete (no data) | Although the health check was successful, the API has not returned any information. This can be due to the API being configured not to send content in response to health check requests. |
| 500 Internal Server Error | Unhealthy | The API could be down, or some of its crucial components could be malfunctioning. |
| 503 Service Unavailable | Temporarily unavailable | A temporary issue, such as overload or maintenance, means the API is unavailable temporarily. |
| 404 Not Found | Endpoint missing or misconfigured | Either the health check endpoint doesn’t exist or there’s something wrong with the configuration of the API. |
| 429 Too Many Requests | Rate Limiting Active | The API has received too many requests, with rate limiting/throttling resulting in this response. |
| 504 Gateway Timeout | Timeout (External Dependency Issue) | The API was waiting for an external service or resource, such as a database, to respond, but timed out while waiting. |
| 401 Unauthorized | Authentication Required | The API didn’t permit the health check to take place due to a permissions issue. |
Consider protecting your health check endpoint
Be sure to implement authentication and authorization mechanisms to prevent unauthorized access to your API health check endpoint. Regularly review and test your security arrangements to ensure that everything is functioning as it should.
Take advantage of load balancing
If you have multiple instances of an API, you can use health checks in combination with a load balancer to distribute incoming requests to healthy instances and avoid those that are exhibiting unhealthy behavior or are unresponsive.
Conclusion
Implementing proactive API health checks means you can avoid service disruption and the potential impact this could have on your end users. By embracing the best practices above, you can ensure you get maximum value from your API health checks.
Health checks sorted now? Great. Why not dive into these API governance topics next?
