Working with Log Drains

From the Vercel dashboard, go to Team Settings > Log Drains.

Select one or more sources to collect log drains.

The log data is typically collected from various sources, which will be forwarded to your webhook over a network connection. Make sure you select one of these sources when you add a new log drain:

• Static: Collect logs for static assets like HTML and CSS files
• Edge: Outputs log data from Edge Functions like Middleware
• Lambda: Outputs log data from Vercel Functions like API Routes
• External: Collect log results for external rewrites to a different domain
• Build: Outputs log data from the Build Step

Select the delivery format for the collected log drains.

Select the mode that decides the format in which your log data gets delivered. You can to choose from the following format types:

• JSON: With the JSON format, the URL receives a HTTPS or HTTP request with a JSON array on the POST body.
• NDJSON: With the Newline Delimited JSON (NDJSON) format, the URL receives a HTTPS or HTTP POST request with JSON objects delimited by newline (\\n) on the HTTP POST body.

Choose the scope of project(s) to collect log drains.

After deciding the format, choose the scope of team projects for which logs will be collected. You can do it for all or some specific projects based on your requirements.

Choose the target branch and/or environment to collect log drains.

You can optionally configure the target branch and environment (preview or production) type to filter log results. This option is disabled by default, but you can toggle it to get customized filtered results based on your selection.

Define the endpoint URL for the log drains.

The log drains endpoint, which acts as the destination for your logs. All logs data will be forwarded to this URL as a POST request. Once added, Vercel asks you to "Verify" the endpoint. The purpose is to validate the URL ownership that responds with a status code 200 with a header. For example:

If you are unable to complete the endpoint verification step, it's recommended to contact Vercel support team.

Add custom headers to protect your endpoint URLs.

You can optionally add up to 5 custom headers to your log drains URL because most of the log providers require an auth header (i.e., Authorization: Bearer[TOKEN] ) and/or additional metadata sent as header (i.e., target dataset). This feature helps send API keys to additional meta information to the receiver.

Once you have set up the log drains and specified the endpoint URL, click the "Add Log Drain" button, and Vercel will start sending logs to the log drain whenever your application generates them.

You can also click the "Test Log Drain" button to trigger a sample log (corresponding to the selected source(s)) to the target endpoint, so you can ensure the configuration is correct even before adding the log drain.

View all your new and existing configured log drains in a list view.

After the endpoint is confirmed and successfully verified, the logs will start to flow and appear in your Custom log drains list. While in beta, you can create and use up to 5 custom log drains at one time.