Top Tools to Make Debugging APIs Easier
Integrating with APIs can be challenging. Each with its own documentation format, SDK patterns, and authentication quirks. Once you get the integration up and running, the harder step is testing and debugging any problems. This part can be exploratory—before you finish building—or as part of problem resolution.
While you can certainly debug within your codebase, by testing methods and reviewing logs, it can be beneficial to isolate the API calls by using one of the many API testing tools available.
Rather than list the pros and cons of each, let's focus on what makes each tool unique and worth trying.
Cost: Free + Paid Plans
Postman is an institution in this space. It's been around for years, and went from a small app that made API calls into the full ecosystem that it is today. While Postman's primary use case is building and managing your own APIs, their emphasis on encouraging third-parties to publish collections has made it a great tool for exploring and debugging web services. These collections are what make Postman a fantastic tool for debugging external API calls.
Some providers, like Zendesk, link directly to their Postman collections in their documentation. Others can be found on Postman's Explore page, and then opened within the Postman app. Once installed, you can explore endpoints and resources with minimal setup.
Learn more about Postman.
Hoppscotch started as a faster, browser-first alternative to Postman, called Postwoman. It has since been rebranded and continues to add features. Its main benefits are speed and availability. It is also open source, and can even run as a browser extension or progressive web app (PWA).
Learn more about Hoppscotch.
Cost: Free Trial, then $49.99
Moving on to platform-specific applications, Paw is a paid Mac application for interacting with APIs. Like many of the others, it's core focus is on providing a tool to build, test, and document your own APIs. Perhaps Paw's greatest selling point is the UI. Compared to many of the other application's on this list, it really feels like quality Mac-first software. It also offers Team functionality, and an interesting feature called Pawprint that lets you share request/response pairs via a URL, even if the receiver doesn't use Paw.
Learn more about Paw.
Cost: Free + Paid plans.
Insomnia is another API client that lets you design, debug, and test APIs. Unlike some of the other "all-inclusive" applications, Insomnia splits the API designer functionality into a seperate app. This makes the UI much more approachable, and makes it easier to quickly try out a new request without excess setup and configuration.
One additional tool that you can find in their documentation is a CLI version called Inso. It allows you to use the functionality from both their core Insomnia client as well as the designer app, right from the command line, and even from within CI/CD environments.
Learn more about Insomnia.
Cost: Free + Paid plans
While the rest of the applications in this list are centered around allowing you to directly interface with APIs, Fiddler takes a different approach. It is more of a general purpose web debugging tool. It acts as a proxy to capture local requests between your device and the internet. This means you can run your application locally, and inspect any outgoing requests and incoming responses from the Fiddler application.
This approach can be useful for live-debugging, but it also allows you to mock requests and responses that match specific rules. Combined with features around creating collections of requests and responses, and the ability to collaborate with a team, this approach could really help debugging more complex API problems.
Learn more about Fiddler
Cost: Free + Paid plans
HTTP Toolkit is another proxy-style tool like Fiddler, but it is much easier to use and allows you to target specific apps and devices. Where I had trouble getting Fiddler to recognize calls made from my terminal, HTTP Toolkit just worked immediately. The Pro plans offer some really interesting features, such as modifying calls as they are sent, simulating timeouts, and simulating connection failures. In a lot of ways, it feels like the browser's "Network" panel, but for any application.
There's clearly a goal of developer productivity, shown through small touches like inline documentation for status codes and headers, as well as the ability to export code for the API call itself in a variety of languages. It's also open source, which is always a nice bonus.
Learn more about HTTP Toolkit
Cost: Free + Paid plans
Bearer takes a different approach, in that it monitors APIs from within your application with minimal code changes. Any common issues are detected and collected in the dashboard, but you can also set up custom rules for edge case problems. This is a great way to actively debug, but also passively keep watch for unexpected problems that may arise with web services.
Learn more about Bearer
Finding the right tool
Choosing the right tool, not just for the task, but also for your workflow can be a challenge. Fortunately, all of the options we've looked at here are free or offer free trials to get you started. Whether you're doing some exploratory testing, debugging a rare problem, or looking for a way to make your integrations more reliable, there's an existing API debugging and testing tool that can help.