Once you've successfully set up your Project on your desired Domain, you can start keeping an eye on its performance and behavior, to make sure that your visitors are provided with the best experience possible.
Even without your involvement, Vercel will guarantee that your Project and Deployments can handle any amount of traffic well and will also help mitigate L3 and L4 DDoS attacks.
However, this requires that your Project's source code is working reliably, doesn't cause any errors to occur, and doesn't slow down incoming requests. The following features will help you achieve that:
To let you easily identify any potential reliability issues with your Deployments, Vercel automatically records and stores any unhandled errors that might be occuring within your Functions, whenever they're invoked.
Those errors can be inspected on the Functions tab of every Deployment on the dashboard. If you'd like to view the errors of your current Production Deployment, for example, click "Runtime Logs" on the Project View:
Afterwards, you will be presented with logs for all incoming requests arriving to your Functions. If a new request appears, its resulting logs will immediately be surfaced in realtime on this view:
Like this, you can monitor any kind of log that is provided by your Functions (which includes errors). The logs will be available as long you're looking at that particular page. Once it's closed, the list of logs will reset to being empty, and wait for new incoming requests.
In the case of errors, however, you will always be able to access the logs restroactively by selecting the "Errors" filter, so you don't have to worry about missing them.
Whenever an unhandled error or an unexpected log shows up here, you can then adjust your Project's source code to resolve these problems, and, as a result, improve its reliability.
If you want to, you can learn more about the concept of Logs on Vercel.
In addition to helping you guarantee that your source code runs reliably, Vercel also helps you ensure that it runs fast, and that your end users can enjoy a snappy experience.
For this, Vercel provides a dedicated Analytics tab for every Project, which uses data that's automatically collected from end user devices to help you understand how your application performs in the wild.
While most tools only let you test your site's performance artificially, Vercel Analytics are computed purely from the actual end user experience, and therefore provide a better picture of what has to be improved.
To enable them, navigate to the Analytics tab of your Project:
Once the feature is enabled, every visit to your application will automatically contribute to a Real Experience Score, which is comprised from a collection of metrics defined and standardized by Google, for helping you understand the performance of your application in the simplest way possible:
An example of a Real Experience Score.
To provide your users with a fast experience, make sure that every change you make to your Project from here on out contributes to improving this score, until it's green, if that's not already the case.
Over time, once you've gotten to a point where the Real Experience Score is green, the Vercel dashboard will help you ensure it stays that way.
If you want to, you can learn more about the concept of Analytics on Vercel.
With Logs and Analytics, you will be able to improve the reliability and performance of your app, to the point where it eventually provides the best user experience possible.
In addition, it's important to also guarantee that, going forward, no additional regressions in reliability or performance will find their way into Production.
This can be accomplished with Checks API, which perform any validation of your choice every time a Preview Deployment is created, and will prevent it from being merged into Production if the validation doesn't match your expectations:
The depiction of how the Checks lifecycle works.
The above example shows the lifecycle of how checks work on a Deployment. If you want to, you can learn more about the concept of Checks on Vercel.
The Monitoring tab allows you to visualize, explore, and monitor your usage and traffic data with a powerful query editor. You can use example queries or create your own.
That's it. Now you're set up!
You've learned everything you need to know about how to be successful on Vercel. From here on out, feel free to check out the additional documentation sections below, if you'd like to learn more about building sophisticated applications on Vercel: