6 min read

Runtime Logs

Learn how to search, inspect, and share your runtime logs with the Logs tab.
Table of Contents

Runtime Logs are available on all plans

Those with the owner, member, developer role can access this feature

The Logs tab allows you to view, search, inspect, and share your runtime logs without any third-party integration. You can also filter and group your runtime logs based on the relevant fields.

You can only view runtime logs from the Logs tab. Build logs can be accessed from the production deployment tile.

Runtime logs include all logs generated by Serverless and Edge Function invocations in both preview and production deployments. These log results provide information about the output for your functions as well as the console.log output.

With runtime logs:

  • Logs are shown in realtime
  • Each action of writing to standard output, such as using console.log, results in a separate log entry
  • Each of those logs are 4 KB per line

To view runtime logs:

  1. From the dashboard, select the project that you wish to see the logs for
  2. Select the Logs tab from your project overview
  3. From here you can view, filter, and search through the runtime logs. Each log row shares basic info about the request, like execution, domain name, HTTP status, function type, and RequestId.
Layout to visualize the runtime logs.
Layout to visualize the runtime logs.

You can use the following filters from the left sidebar to get a refined search experience.

You can filter runtime logs based on a specific timeline. It can vary from the past hour, last 3 days, or a custom timespan depending on your account type. You can use the Live mode option to follow the logs in real-time.

Layout to visualize the runtime logs in live mode.
Layout to visualize the runtime logs in live mode.
All displayed dates and times are in UTC.

You can filter runtime logs by three kinds of levels: Info, Warning, and Error. Streaming Functions will always preserve the original intent:

SourceStreaming FunctionsNon-streaming Functions
stdout (e.g. console.log)infoinfo
stderr (e.g. console.error)errorerror
console.warnwarningerror

Additionally:

  • Requests with a status code of 4xx are considered a Warning
  • Requests with a status code of 5xx are considered Error
  • All other requests are considered Info

These levels are highlighted with different colors for example, yellow for warnings and red for errors. This color coding is beneficial with debugging; you can identify the failed requests and the reason behind the failure.

You can filter and analyze logs for one or more functions defined in your project. The log output is generated for the Serverless Functions, Edge Functions, and Edge Middleware.

You can view logs for one or more domains and subdomains attached to your team’s project. Alternatively, you can use the Search hosts... field to navigate to the desired host.

Like host and functions, you can filter your logs based on deployments URLs.

Using the type filter, you can search for four logs types generated as a result of:

TypeDescription
Serverless FunctionsLogs generated from your Serverless Functions invocations. Log details include additional runtime Request Id details and other basic info
Edge MiddlewareLogs generated as a result of your Edge Middleware invocations
Edge FunctionsLogs requests generated from your Edge Functions. Log info includes time, domain, and the request method
RequestLogs generated from either ISR or external redirections

You can filter your logs based on the request method used by a function such as GET or POST.

You can filter your logs based on the cache behavior such as HIT or MISS.

Log Presets allow you to save your selected filters for later use. You can save presets to either My Project Presets (related to your personal account) or Team Project Presets. Personal presets can only be viewed and edited by the user who created them.

Presets are tied to specific projects. If you switch to another project, you will not see the saved presets.

To save a preset, make a change to the filters in the left sidebar and select the Save button. You can then choose the scoping group to save the preset to, either Personal or Team.

Layout to save log presets.
Layout to save log presets.

You can use the main search field to filter logs by their messages. In the current search state, filtered log results are sorted chronologically, with the most recent first. Filtered values can also be searched from the main search bar.

ValueDescription
FunctionThe function name
LevelThe level type. Can be Info, Warning, or Error
TypeCan be Request, Serverless Function, Edge Middleware, and Edge Function
HostName of the domain or subdomain for which the log was generated
DeploymentThe name of your deployment
MethodThe request method used. For example GET, POST etc.
CacheCache status with the values HIT, MISS, STALE, BYPASS, PRERENDER or REVALIDATED
StatusHTTP status code for the log message
RequestIDUnique identifier of request. This is visible on a 404 page, for example.

This free text search feature is limited to the message field. Other fields can be filtered using the left sidebar or the filters in the search bar.

You can view details for each generated runtime log to analyze and improve your debugging experience. When you click a log from the list, the following details appear in the right sidebar:

InfoDescription
Log NameTitle of the log generated
TimeTimestamp at which the log was recorded in UTC
Status CodeHTTP status code for the log message
HostName of the domain or subdomain for which the log was generated
Request IdUnique identifier of request created only for runtime logs
Request User AgentName of the browser from which the request originated
LevelThe level type for example, Info, Warning, or Error
CacheCache status with the values HIT, MISS, STALE, BYPASS, PRERENDER or REVALIDATED
TypeCan be Request, Serverless Function, Edge Middleware, and Edge Function
FunctionThe function name
LocationThe geographical region for Serverless and Edge Functions access
RuntimeName of the JavaScript runtime environment for Node.js (info only applies to Serverless Function type)
Duration/LimitTime duration for the log record result (info only applies to Serverless Function type)
Memory used/LimitThe size of memory that was consumed by the function (info only applies to Serverless Function type)
Log MessageA detailed log message with additional details for RequestId, Billed Duration, Max Memory Used, etc. Log messages that push the log over 4 KB can be truncated to only show tail logs

Towards the end of the log results window is a button called Show New Logs. By default, it is set to display log results for the past 30 minutes.

Click this button, and it loads new log rows. The latest entries are added based on the selected filters.

You can share a log entry with other team members to view the particular log and context you are looking at. Click on the log you want to share, copy the current URL of your browser, and send it to team members through the medium of your choice.

Logs are streamed, and there is no limit on how many times you can output log data for each function invocation. Each log output can be up to 4 KB. Logs that exceed this will be truncated.

Runtime logs are stored with the following observability limits:

PlanRetention timeLog entries
Hobby1 hour of logsUp to 4000 rows of log data
Pro1 day of logsUp to 100,000 rows of log data
Enterprise3 days of logsUp to 60 million rows of log data

If you exceed the log entry limits, you can only query the most recent logs.

Last updated on July 13, 2024