Function logs

Netlify provides logs in the Netlify UI to help you observe and troubleshoot serverless functions in your current published deploy, branch deploys, and Deploy Previews.

Access function logs

1. In the Netlify UI, for your chosen site, go to Logs > Functions.
2. Select a function from the list to open the log for that function.

By default, the Functions list displays the functions in the current published deploy. To find functions on another deploy, you can use the search field at the top of the list. You can start typing to jump to a particular branch, or find a Deploy Preview by number.

Team Owners and Developers can monitor the function logs for a specific deploy by going to the Function logs tab of the Netlify Drawer in a collaborative Deploy Preview.

Log contents

Netlify displays a log for each function, including:

• Start of each invocation
• Any console.log() statements you include in your function code
• Log statements as each background function is executed

Note that function log retention limits apply and may impact what the Netlify UI displays.

Date filter

By default, the function log displays a live tail of the latest activity in Real-time. You can also filter to review data from a specific time period, including the Last hour, Last day, Last 7 days, or select Custom to input a specific date and time range.

Text filter

You can filter the contents of the log with simple text matches on request ID, message, or log level. Some common log levels include:

• INFO
• ERROR
• WARN
• FATAL
• DEBUG
• TRACE

Log retention and limits

Logs are retained for at least 24 hours of function activity, even after a new function deployment. This log retention period increases to 7 days for certain pricing plans.

Log limitations

For functions using the Lambda compatibility mode, historical function log output is limited to 4 KB total per invocation. If a log’s output exceeds 4 KB, only the last 4 KB of the log is retained and the log message will be truncated.

Log Drains

This feature is available on Enterprise plans.

You can connect your function logs to third-party monitoring services for analysis using Netlify’s Log Drains feature. Check out our Log Drains doc for more information.

For logs sent via Log Drains, the output for a single log entry is limited to 700 KB.

Function Metrics

With Function Metrics, you can get insights into the performance, reliability, and usage patterns of functions on your site. By analyzing success and error rates alongside other metrics, such as invocation count and function duration, you can optimize performance, troubleshoot issues, and make data-driven decisions to enhance the overall quality and user experience of your projects.